JPH10294174A - Power control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effect stable arc ignition in a DC arc furnace by suppressing a rush current which is generated during the transition from arc extinction to the short circuit of load at the time of arc ignition. SOLUTION: Power is supplied to an arc furnace 3, and operation of a rectifier 2 whose output current is controlled by voltage feedforward and current feedback is effected during the short circuit of load at the time of arc ignition. A voltage converter 6 which detects the output voltage of the rectifier 2 is provided at its output with a switch 15 to set the voltage feedforward output at zero during arc ignition to suppress a rush current produced by the feedforward of a no-load voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply control device for more stably controlling a DC power supply device of an arc furnace in which a load fluctuates greatly by using both current feedback control and voltage feedforward control.

[0002]

2. Description of the Related Art FIG. 65 shows a basic circuit of a DC arc furnace described in, for example, "Norio Ao: Good Use of Arc Heating". In the figure, 1 is a transformer for stepping down a system voltage to an appropriate voltage, and 2 is a rectifier using a switching element for converting an AC voltage stepped down by the transformer 1 into DC power. However, this may be replaced with a power switching element such as a power FET or GTO.

[0003] Reference numeral 3 denotes an arc furnace body to which a DC current is supplied from the rectifier 2 through a DC reactor 24. A positive potential is applied to the furnace bottom electrode of the arc furnace furnace body 3 from the rectifier 2 through the DC reactor 24, and a negative potential is applied to the arc furnace electrode described later from the rectifier 2 through the DC reactor 24. Then, a desired arc current flows between the arc furnace electrode and the furnace bottom electrode to generate an arc from the tip of the arc furnace electrode. The above-described circuit elements constitute a main circuit of the power control device for the arc furnace.

[0004] Reference numeral 10 denotes a current detector for detecting a secondary current output from the transformer 1 to the rectifier 2, and 14 denotes a current having an appropriate value for controlling the secondary current detected by the current detector 10. A current converter 7 for converting the current value into a detected value, a subtractor 7 for subtracting the current detected value converted by the current converter 14 from a preset current set value to obtain a current deviation, and 9 a current deviation obtained by the subtractor 7 Is a proportional integrator that outputs a control signal by performing a proportional-integral operation so that is equal to 0, 11 is a voltage detector that detects a voltage (arc voltage) between the arc furnace electrode and the bottom electrode, and 6 is a detected arc voltage. Is a voltage converter that converts the voltage feedforward amount into a voltage feedforward amount, and an adder 8 that adds the voltage feedforward amount converted by the voltage converter 6 and the control signal output from the proportional integrator 9 to output an addition signal. Is a phase angle control device. Phase angle control device 5 obtains the ignition phase angle of the rectifier device 2, such as the current deviation becomes zero between the preset current set value and the current detection value based on the addition signal. The circuit elements constitute the current control system of the power supply device of the arc furnace.

Reference numeral 4 denotes an arc furnace electrode 4, 12 is an electrode lifting / lowering device for raising / lowering the arc furnace electrode 4 in the arc furnace 3.
Is an electrode elevation control device, and the electrode elevation control device 13
Calculates a control signal such that the deviation voltage between the arc voltage converted by the voltage converter 6 and the preset arc voltage set value becomes 0, and supplies the control signal to the electrode lifting / lowering device 12. Here, the value of the arc voltage changes depending on the length of the arc column depending on the height of the arc furnace electrode 4. Therefore, a desired arc voltage can be obtained by adjusting the height of the arc furnace electrode 4. The voltage control system of the power supply device of the arc furnace is constituted by the above circuit elements.

Next, the operation of the conventional apparatus will be described. After the voltage of the system is reduced to an AC voltage having an appropriate value by the transformer 1, the rectifier 2 converts the AC voltage into a DC voltage. When a positive potential of the DC voltage is applied to the bottom electrode of the arc furnace body 3 through the DC reactor 24 and a negative potential is applied to the arc furnace electrode 4 through the DC reactor 24, the potential between the arc furnace body 3 and the arc furnace electrode 4 is increased. Arc current flows through the electrode 4 of the arc furnace.
An arc is generated from the tip of the arc furnace to melt the scrap and the like in the arc furnace.

Further, the ignition phase angle of the switching element in the rectifier 2 is controlled by a gate control signal output from the phase angle controller 5, and the angle between the arc furnace body 3 and the arc furnace electrode 4 from the rectifier 2 is controlled. To control the value of the arc current flowing through. Next, the secondary current detected by the current detection unit 10 is converted by the current converter 14 into an appropriate current detection value. Then, the subtractor 7 obtains a current deviation between the current value and the preset current value.

This current deviation is processed by a proportional integrator or integrator 9 having an appropriate time constant so that the current deviation becomes zero, and the control signal is output to the adder 8. In addition, in the adder 8, since the arc furnace has a large voltage fluctuation, it follows the sharp voltage fluctuation.
The control signal is added to the detected voltage value (voltage feedforward amount) detected by the voltage converter 6 and converted by the voltage converter 6, and the added signal is input to the phase angle controller 5.

Then, the phase angle control device 5 determines the firing phase angle of the rectifier 2 so that the current deviation between the current detection value and the preset current set value becomes 0 based on the addition signal, and performs gate control. The signal is output to the rectifier 2 as a signal. As described above, the current feedback loop is formed in the current control system, and the voltage feedforward loop is formed in the voltage control system to control the value of the arc current from the rectifier 2.

The arc voltage determined by the position of the arc furnace electrode 4, that is, the arc length, is the voltage deviation between the detected arc voltage output from the voltage converter 6 and the voltage set value set by the electrode elevation control device 13. The position of the electrode of the arc furnace 4, that is, the arc voltage is controlled to a voltage set value even by raising and lowering the electrode raising and lowering device 12 so that the voltage deviation becomes zero, obtained by the electrode raising and lowering control device 13.

[0011]

Since the conventional power supply control device is constructed as described above, when the arc is cut off, it is located between the arc furnace electrode 4 and the arc furnace body 3 before the arc is ignited. The state is such that the arc current is not flowing despite the generation of the no-load voltage. At this time, since the output from the current detector 10 is 0, the output from the adder 7 is positive even if the current set value is kept low, and the proportional integrator 9 stores the electric charge and the output is determined by the control power supply voltage. Value (for example, 13
V).

In this state, the arc electrode is brought into contact with the scrap in the furnace to cause arc ignition or load short-circuit, and the current actually starts flowing to the rectifier 2, and a current feedback loop is formed by the deviation current from the subtractor 7. Even so, the output from the proportional integrator 9 remains at the positive saturation voltage for a certain time determined by the integration time constant.

As a result, the saturation voltage is input to the phase angle control device 5, and the ignition phase angle of the switching element is shifted at a stroke in the direction of 0 degrees, so that a very large inrush current flows to destroy the switching element. There was a problem.

In the voltage feedforward system, when the arc is cut off, a very large feedforward voltage is applied from the voltage converter 6 because no load voltage is applied between the arc furnace electrode 4 and the arc furnace body 3. When input to the phase angle control device 5, the ignition phase angle of the switching element is shifted at a stretch in the direction of 0 degrees, causing a problem that a very large inrush current flows to destroy the switching element.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and suppresses an inrush current generated when the load shifts when a load is short-circuited when an arc breaks after an arc break. It is an object of the present invention to obtain a power supply control device capable of performing ignition.

[0016]

According to a first aspect of the present invention, there is provided a power supply control device which performs a proportional integral calculation on a deviation between a load current flowing through a switching element type rectifier for supplying DC power to a load and a preset load current. A current feedback control unit including a proportional integrator that generates a control signal based on the deviation and outputs the control signal to the rectifier, detects a voltage related to the load, and responds to the control signal so as to follow the load voltage. A voltage feedforward control means for inputting an added output obtained by adding a voltage feedforward output corresponding to the load voltage in an adder to the rectifier, and wherein the load is turned on again after the load is cut off. A control signal limiting means for limiting a control signal to be output to the rectifier, which suppresses an inrush current flowing through the rectifier when the load is turned on again. .

According to a second aspect of the present invention, the control signal limiting means limits at least one of the output signal of the proportional integrator of the current feedback control means, the voltage feedforward output and the addition output.

According to a third aspect of the present invention, in the power supply control device, the control signal limiting means for limiting the voltage feedforward output switches the input to the adder from the voltage feedforward output to an initial value of a predetermined level when the load is turned on again. This is configured by a first switch.

According to a fourth aspect of the present invention, in the power supply control device, the control signal limiting means for limiting the voltage feedforward output multiplies the voltage feedforward output when the load is turned on again by a predetermined coefficient value to an initial value of a predetermined level. After the load is applied, the coefficient value is increased to 1 to form a multiplying means.

According to a fifth aspect of the present invention, in the power supply control device, the control signal limiting means for limiting the voltage feedforward output limits the voltage feedforward performed at the time of reloading the load to a constant value, and inputs the voltage feedforward to the adder, and the load control is performed. The rest consists of a limiter that increases the limit value.

According to a sixth aspect of the present invention, in the power supply control device, the control signal limiting means for limiting the output signal of the proportional integrator switches an input to the adder to an initial value of a predetermined level from the output signal when the load is turned on again. This is constituted by a second switch for inputting.

According to a seventh aspect of the present invention, in the power supply control device, the control signal limiting means for limiting the output signal of the proportional integrator is multiplied by a predetermined coefficient value when the load is turned on again to set an initial value of a predetermined level. It is configured by a multiplying means which inputs the load to the adder and increases the coefficient value to 1 after the load is applied.

In the power supply control device according to the present invention, the limiter for limiting the output signal is incorporated in the proportional integrator to constitute control signal limiting means. When the load is turned on again, the output signal is set to a constant value by the limiter. The limit value is input to the adding unit, and after the load is applied, the limit value of the limiter is increased.

According to a ninth aspect of the present invention, in the power supply control device, the control signal limiting means for limiting the addition output includes a third switch for switching the input to the rectifier and switching the addition output to an initial value of a predetermined level when the load is turned on again. It consists of.

According to a tenth aspect of the present invention, in the power supply control device, control signal limiting means for limiting the added output of the output signal of the proportional integrator and the voltage feedforward output is added to the added output input to the rectifier when the load is turned on again. The multiplication means is configured to multiply by a predetermined coefficient value to obtain an initial value of a predetermined level, and to increase the coefficient value to 1 after a load is applied.

The power supply control device according to claim 11, wherein the control signal limiting means for limiting the added output limits the added output input to the rectifier to a constant value when the load is turned on again, and sets the limit value after the load is turned on. The limiter is configured to increase the number.

According to a twelfth aspect of the present invention, in the power supply control apparatus, each of the voltage feedforward output and the control signal limiting means for limiting the output of the proportional integrator is changed from the voltage feedforward output to the input to the adding section when the load is turned on again. A first switch for switching and inputting to an initial value of a predetermined level, and a second switch for switching and inputting the input to the adding section to an initial value of a predetermined level from the output of the proportional integrator when the load is turned on again. .

According to a thirteenth aspect of the present invention, the power supply control device is configured to replace at least one multiplier of each of the switches. According to a fourteenth aspect of the present invention, at least one of the switches is replaced with a limiter.

A power supply control device according to claim 15 is configured such that one of the switches is replaced by a limiter and the other is replaced by a multiplier.

According to a sixteenth aspect of the present invention, each of the control signal limiting means for limiting the voltage feedforward output and the addition output is switched from the voltage feedforward output to an initial value of a predetermined level when the load is turned on again. 1 and a third switch for switching and inputting the added output to an initial value of a predetermined level when the load is turned on again.

According to a seventeenth aspect of the present invention, at least one of the switches is replaced with a multiplier.

A power supply control device according to claim 18, wherein at least one of the switches is replaced by a limiter.

The power supply control device according to claim 19 is configured such that one of the switches is replaced by a limiter and the other is replaced by a multiplier.

According to a twentieth aspect of the present invention, each of the control signal limiting means for limiting the voltage feedforward output, the addition output and the output of the proportional integrator is controlled by the voltage feedforward output when the load is turned on again. A first switch for switching and inputting the initial value of the level;
A third switch configured to switch and input the output of the proportional integrator to an initial value of a predetermined level when reloading the load, and a second switch configured to switch and input the output of the proportional integrator to an initial value of a predetermined level when reloading the load. It is.

According to a twenty-first aspect of the present invention, at least one of the switches is replaced with a multiplier.

According to a twenty-second aspect of the present invention, at least one of the switches is replaced with a limiter.

According to a twenty-third aspect of the present invention, two of the switches are replaced by multipliers and one of the switches is replaced by a limiter.

According to a twenty-fourth aspect of the present invention, two of the switches are replaced by limiters, and one of the switches is replaced by a multiplier.

According to a twenty-fifth aspect of the present invention, one of the switches is replaced by a limiter and one is replaced by a multiplier.

According to a twenty-sixth aspect of the present invention, the control signal limiting means for limiting the addition output and the output of the proportional integrator limits the addition output to an initial value of a predetermined level when the load is turned on again. A third switch for inputting, and a second switch for switching and outputting the output of the proportional integrator to an initial value of a predetermined level when the load is turned on again.

According to a twenty-seventh aspect of the present invention, at least one of the switches is replaced with a multiplier.

According to a twenty-eighth aspect of the present invention, at least one of the switches is replaced with a limiter.

According to a twenty-ninth aspect of the present invention, one of the switches is replaced by a limiter and one is replaced by a multiplier.

[0044]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, Embodiment 1 of the present invention will be described with reference to FIG. In the figure, the same reference numerals as those in FIG. 65 indicate the same or corresponding parts. In this embodiment, the feedforward output from the voltage converter 6 is input to the adder 8 during the voltage feedforward control, and when the arc is cut or before the arc is turned off, an initial value setting means (not shown) is set. There is provided a switch 15 for switching between the output of the voltage converter 6 and the output of an initial value setting means (not shown) so that the initial value is input to the adder 8.

As an operation of this device, at the time of normal arc control, the switch 15 is switched to the output of the voltage converter 6 to form a voltage feedforward loop and a current feedback loop, and perform the same operation as the conventional device. However, when the arc is cut or before the arc is turned off, since a no-load voltage is applied between the arc furnace electrode 4 and the arc furnace body 3, a very large feedforward voltage is applied to the voltage converter 6. Is output to the phase angle control device 5 to widen the conduction angle of the switching element in the rectifier 2. If the load is short-circuited in this state, an inrush current flows through the switching element.

In order to avoid such a situation, when the arc is cut, or when it is determined by the detection signal from the current detection unit 10 or the voltage detection unit 11 that the current is before the arc is turned off, the arc is turned off. At the time of arcing, the current set value is set to 0 by control means (not shown) to prevent saturation of the proportional integrator 9, the switch 15 is switched to the output of the initial value setting means, and the initial value set by the initial value setting means is added. Table 8
To enter.

The initial value set by the initial value setting means is a voltage value for outputting a gate control signal from the phase angle control device 5 so that the ignition phase angle of the switching element in the rectifier 2 becomes 80 to 85 degrees. When the signal is input to the phase angle control device 5 through the adder 8, the gate control signal is input to the switching element, and the output current is reduced.

Then, an arc voltage appears due to generation of an arc current due to a short circuit that brings the arc furnace electrode 4 into contact with the scrap. Thereafter, the arc voltage and the electrode elevation control device 13
The positioning of the arc electrode 4 is performed by the electrode lifting / lowering device 12 until the deviation from the arc voltage set value set in the step becomes zero.
When the arc starts to stabilize, the current set value is returned to the set value, and the switch 15 is switched to the output of the voltage converter 6 to perform current feedback control and voltage feedforward control of arc control. As a result, a voltage feed-forward due to a large no-load voltage is avoided when an arc is disconnected or a load is short-circuited, and an inrush current is prevented from flowing through the switching element.

Embodiment 2 In the first embodiment, the switch 15 is switched immediately after the arc is stabilized to switch to the voltage feedforward control to the arc voltage.
In the present embodiment, the voltage feedforward amount is gradually increased at the time of arc ignition, and is input to the adder 8.

Hereinafter, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the switch 15 is changed to a multiplier 16 in the circuit of FIG. The multiplier 16 reduces the output of the adder 6 corresponding to no-load voltage to an initial value by changing the coefficient value to 1 or less at the time of arc firing by the coefficient value control device 16a. Is gradually increased by increasing the voltage feedforward amount.

The basic operation of this embodiment is the same as that of the first embodiment. Before the arc is turned off and when the arc is cut, the coefficient value of the multiplier 16 is adjusted to 1 or less by the coefficient value control device 16a to make the output of the voltage converter 6 a value corresponding to the initial value, and the adder 8 Is input to the phase angle controller 5 through. At this time, since both the output of the current converter 14 and the current set value are 0, the proportional integrator 9 does not saturate positively.

As a result, the phase angle control device 5 outputs a gate control signal to the rectifier 2 so that the ignition phase angle of the switching element in the rectifier 2 becomes 80 to 85 degrees. The electrode 4 is brought into contact with the scrap, and an arc current due to the short circuit flows to generate an arc voltage.

When the arc is stabilized, the multiplier 1
The coefficient value of No. 6 is increased in one direction by the coefficient value control device 16a, and the current set value is returned to the original value to gradually switch to the current feedback control and the voltage feedforward control.

Further, when the transformer 1 has a tap changer, even when the tap change is required and the feedforward amount needs to be changed, for example, when the value of the secondary terminal voltage of the transformer changes. It is possible to cope with a change in the feedforward amount only by changing the coefficient value of the multiplier 16.

Embodiment 3 In the second embodiment, the coefficient value of the multiplier 16 is adjusted and the value corresponding to the initial value is input to the adder 8, but when the output of the voltage converter 6 fluctuates, the appropriate value corresponding to the initial value is added to the adder 8. Can not be entered in. Therefore, in the present embodiment, the output is limited to the initial value irrespective of the output change of the voltage converter 6 so that an appropriate value corresponding to the initial value can be obtained regardless of the fluctuation of the output of the voltage converter 6.

Next, a third embodiment of the present invention will be described with reference to FIG. In the present embodiment, the switch 15 is changed to the limiter 17 in the circuit of FIG. 1, and the limit value of the limiter 17 is controlled by the limit value control device 17a before the arc is turned off and when the arc is cut off. The output of the converter 6 is limited to an initial value and input to the adder 8. After the arc break, the limit value is changed by the limit value control device 17a according to the feedforward amount.

The basic operation of this embodiment is the same as that of the first embodiment. Before the arc is turned off and when the arc is cut, the limit value of the limiter 17 is controlled by the limit value control device 17a, the output of the voltage converter 6 is set to a value corresponding to the initial value, and the phase angle control device is passed through the adder 8. Enter 5 As a result, the phase angle control device 5 outputs a gate control signal to the rectifier 2 such that the ignition phase angle of the switching element in the rectifier 2 becomes 80 to 85 degrees.

Then, as in the first embodiment, the arc electrode 4 is brought into contact with the scrap, and an arc current caused by a short circuit flows to generate an arc voltage. Then, the arc is stabilized and the limit value of the limiter 17 is set to the limit value control device 16a.
And the current set value is returned to the original value, and gradually switched to current feedback control and voltage feedforward control.

If the transformer 1 has a tap changer, the tap change is performed, and even if the feedforward amount needs to be changed, such as when the value of the secondary terminal voltage of the transformer changes, the limiter can be used. It is possible to cope with a change in the feedforward amount only by changing the 17 limit values.

Embodiment 4 In each of the first to third embodiments, by setting the current set value to 0, the inrush current due to the feedforward of the no-load voltage and the inrush current at the time of arc ignition due to the saturation of the proportional integrator are suppressed. This embodiment suppresses the inrush current at the time of arc ignition caused by arc interruption and saturation of the proportional integrator before arc ignition without delaying the response of the current feedback control by setting the current set value to 0. The purpose is to:

FIG. 4 is a configuration diagram of the power supply control device according to the present embodiment. In the figure, the same reference numerals as those in FIG. 65 indicate the same or corresponding parts. In the figure, reference numeral 18 denotes a switch for switching the input to the adder 8 between the initial value and the output from the proportional integrator, as in the above embodiments.

The basic operation of this embodiment is the same as that of the first embodiment. When the arc is cut, or when it is determined that the current is before the arc is cut off by the detection signal of the current detection unit 10 or the voltage detection unit 11, the switch 18 is controlled by the control unit (not shown) to output the output of the initial value setting unit. Section, and inputs the initial value set by the initial value setting means to the adder 8.

The initial value set by the initial value setting means is a voltage value at which a gate control signal is output from the phase angle control device 5 so that the ignition phase angle of the switching element in the rectifier 2 becomes 80 to 85 degrees. And input to the phase angle controller 5 through the adder 8. The no-load voltage is initially input to the adder 8, but the scraper is brought into scrap contact with the arc electrode 4 in order to generate an arc, so that the no-load voltage is immediately negligible and becomes a negligible value. Output.

When the initial value is input to the adder 8 and the control signal is input to the phase angle control device 5, the phase angle control device 5 sets the ignition phase angle of the switching element in the rectifier 2 to 80 to 85 degrees. A gate control signal is output to the rectifier 2.

Then, as in the first embodiment, the arc electrode 4 is brought into contact with the scrap, and an arc current due to a short circuit flows to generate an arc voltage. When it is determined from the detected current value and the time constant of the proportional integrator 9 that the output value of the proportional integrator 9 has become equivalent to the initial value, or from the detected voltage value that the arc has been stabilized, the switch 18 is switched to the proportional integrator 9. 9 to switch to current feedback control. Therefore, it is possible to suppress the inrush current of the arc ignition due to the saturation of the proportional integrator 9 before the arc is generated. In the case of this embodiment, since the current set value is not 0, it is possible to immediately start the current feedback control.

Embodiment 5 In the fourth embodiment, the signal input to the adder 8 in the current feedback loop is switched from the output of the proportional integrator to the initial value by the switch 18, but in the present embodiment, the switch 1 is switched as shown in FIG.
8 is changed to the multiplier 19, and the coefficient value of the multiplier 19 is changed by the coefficient value control device 19a according to the change of the feedback amount.

The basic operation of this embodiment is the same as that of the first embodiment. When the arc is cut, or when it is determined before the arc is cut off by the detection signal from the current detection unit 10 or the voltage detection unit 11, the coefficient value of the multiplier 19 is adjusted by the coefficient value control device 19a. The saturation output of the proportional integrator 9 becomes a value corresponding to the initial value and is input to the adder 8.

As a result, the adder 8 causes the phase angle control device 5 to output a gate control signal such that the ignition phase angle of the switching element in the rectifier 2 becomes 80 to 85 degrees. Then, as in the first embodiment, the arc electrode 4 is brought into contact with the scrap, and an arc current due to a short circuit flows to generate an arc voltage.

When the arc is started, a current flows, so that the difference between the detected current value and the set current value is input to the subtractor 7 of the proportional integrator 9 to eliminate the saturation state. When it is determined from the detected current value or the like that the arc is stable, the coefficient value control device 19a gradually increases the limit value of the proportional integrator 9.

Embodiment 6 FIG. In the fifth embodiment, the saturation output of the proportional integrator 9 is multiplied by a coefficient value, and a value corresponding to the initial value is input to the adder 8. However, when the proportional integrator 9 is saturated, the output is limited to correspond to the initial value. May be generated and input to the adder 8.

FIG. 6 is a configuration diagram of the power supply control device according to the present embodiment. In this embodiment, the switch 15 is eliminated and the proportional integrator 9 is replaced with a proportional integrator 20 with a limiter shown in FIG.
The basic operation is the same as that of the first embodiment.

Before the arc is ignited, and when the arc is cut off and the current is not flowing, the output of the proportional integrator saturates to a voltage value (for example, 13 V) determined by the control power supply voltage by the current set value. Therefore, if it is determined that the current detection value output from the current converter 14 is 0, the limit value of the variable limiter of the proportional integrator 20 with limiter is adjusted, and the output is set to a value equivalent to the initial value. And input to the phase angle control device 5 through the adder 8. As a result, the phase angle control device 5 outputs to the switching element a gate control signal capable of maintaining the firing phase angle of the switching element at 85 degrees. Then, as in the first embodiment, the arc electrode 4 is brought into contact with the scrap, and an arc current due to a short circuit flows to generate an arc voltage.

If it is determined from the current detection value of the current converter 14 that a current of, for example, about 5% of the constant current has continuously flowed for 2 seconds or more in the rectifier 2, the stability of the arc is recognized. Then, the limit value of the variable limiter is gradually released to switch to the current feedback control. As a result, the proportional integrator with limiter 20 is saturated when no current is flowing, thereby preventing an inrush current from flowing when a load is short-circuited during arc ignition.

Further, by making the voltage feedforward value correspond to the limit value of the limiter and making the sum of the voltage feedback amount and the maximum value of the current feedforward constant, stable control can be performed even when the arc voltage becomes too large. To do it.

Embodiment 7 In the first to sixth embodiments, the output current of the rectifier 2 is controlled so as to suppress the inrush current at the time of arc ignition in the voltage feedforward loop and the current feedback loop, respectively.

The purpose of this embodiment is to collectively suppress inrush current caused by no-load voltage in the voltage feedforward loop and inrush current caused by the saturation output of the proportional integrator 9 in the current feedback loop. I do. FIG. 7 is a configuration diagram of the power supply control device according to the present embodiment. This embodiment is different from the conventional power supply control device in that the output of the adder 8 and the initial value are interposed between the output of the adder 8 and the input of the phase angle controller 5 which are common parts of the voltage feedforward loop and the current feedback loop. A switch 21 for switching and selecting an initial value by a value setting means is provided.

Next, the operation of this embodiment will be described. The basic operation is the same as in the first embodiment. If it is determined by the above-described means before the arc is ignited or when the arc is cut, the switch 21 is switched by a switch control means (not shown) to input an initial value and input to the phase angle control device 5. As a result, the phase angle control device 5 outputs to the switching element a gate control signal capable of maintaining the firing phase angle of the switching element at 85 degrees. The operation of the switching element enables arc ignition between the arc furnace electrode 3 and scrap in the arc furnace. When the arc is started, a current flows and an arc voltage is generated.

When the load is short-circuited at the time of arc ignition, since the adder and the phase angle control device 5 are not connected, the inrush current due to the feedforward of the no-load voltage and the saturation of the proportional integrator when no current is flowing. Can be blocked.
Then, when it is recognized that the arc is stabilized by the above-described means, the switch 21 is switched by the switch control means to switch between voltage feedforward and current feedback control.

Embodiment 8 FIG. In the seventh embodiment, the initial value is input to the phase angle control device 5 when the arc is fired by switching the switch, and after the arc is stabilized, the switch is switched to the voltage feedforward input by the adder output and the current feedback input by switching the switch. In the present embodiment, after the arc is stabilized, a control signal for gradually narrowing the firing phase angle in accordance with the sum of the voltage feedforward amount and the current feedback amount is input to the phase angle control device 5.

FIG. 8 is a configuration diagram of the power supply control device according to the present embodiment. In the present embodiment, in the conventional power supply control device, the coefficient value control device 22a operates between the output portion of the adder 8 and the input portion of the phase angle control device 5 which are common parts of the voltage feedforward loop and the current feedback loop. Is provided.

Next, the operation of the present embodiment will be described. The basic operation is the same as in the first embodiment. Before the arc is ignited, and when the arc is cut, when a control signal, which is an addition value of the no-load voltage detection value output from the voltage converter and the saturation output value of the proportional integrator, is multiplied by a coefficient value, The coefficient value is controlled by the coefficient value control device 22a so that the integrated value becomes a value corresponding to the initial value. In this case, the coefficient value is the saturation output of the proportional integrator (almost 15 V DC).
And a coefficient value smaller than 1 is selected so that the sum of the detected no-load voltage value and the no-load voltage detection value becomes a certain small voltage value.

Then, the initial value obtained by multiplying the control signal from the adder 8 by the coefficient value by the multiplier is input to the phase angle control device 5. As a result, the phase angle control device 5 outputs to the switching element a gate control signal capable of maintaining the firing phase angle of the switching element at 85 degrees. The operation of the switching element enables arc ignition between the arc furnace electrode 3 and scrap in the arc furnace. When the arc is started, a current flows to generate an arc voltage.

As a result, when the load is short-circuited at the time of arc ignition,
Inrush current due to feed-forward of no-load voltage and saturation of the proportional integrator when no current is flowing can be prevented. When it is recognized that the arc is stabilized by the above-described means, the coefficient value control device 22a gradually increases the coefficient value, and controls the power supply by directly inputting the output of the adder 22 to the phase angle control device 5. Switch to voltage feedforward control and current feedback control.

Embodiment 9 FIG. In the eighth embodiment, the coefficient value in the multiplier is reduced at the time of arc ignition, and the adder 8
The initial value obtained by multiplying the added value by the coefficient value is input to the phase angle control device 5. In the present embodiment, the level of the control signal from the adder 8 is limited to an initial value by a limiter and input to the phase angle control device 5 at the time of arc ignition. After the arc is stabilized, the restriction is gradually released in accordance with the voltage feedforward amount and the current feedback amount, and the ignition phase angle is reduced to 85.
A control signal of a voltage level extending in the direction of 0 degree from the degree is input to the phase angle control device 5 from the limiter.

FIG. 9 is a configuration diagram of the power supply control device according to the present embodiment. In this embodiment, in the conventional power supply control device, the limit value control device 23 restricts between the output portion of the adder 8 and the input portion of the phase angle control device 5 which are common parts to the voltage feedforward loop and the current feedback loop. A limiter 23a for controlling the value is provided.

Next, the operation of this embodiment will be described. The basic operation is the same as in the first embodiment. Before the ignition of the arc or when the arc is cut, the level of the control signal, which is the sum of the no-load voltage detection value output from the voltage converter and the saturation output value of the proportional integrator, is limited to a value equivalent to the initial value. The limit value of the limiter 23a is controlled by the limit value control device 22a so that the limit value is controlled. In this case, the limit value is selected so that the sum of the saturation output (approximately 15 V DC) of the proportional integrator and the no-load voltage detection value becomes a certain small voltage value.

The control signal from the adder 8 is limited by the limiter 23a to a value corresponding to the initial value, and
Is input to The phase angle control device 5 outputs a gate control signal capable of maintaining the firing phase angle of the switching element at 85 degrees to the switching element. The operation of the switching element enables arc ignition between the arc furnace electrode 3 and scrap in the arc furnace. When the arc ignition is started, a current flows to generate an arc voltage.

As a result, when the load is short-circuited at the time of arc ignition,
Inrush current due to feed-forward of no-load voltage and saturation of the proportional integrator when no current is flowing can be prevented. When the means described above recognizes that the arc has become stable, the limit value control device 23a gradually releases the limit, and the output of the adder 22 is directly input to the phase angle control device 5 so that the power of the arc furnace power supply is controlled. The control is switched to voltage feedforward control and current feedback control.

Embodiment 10 FIG. In the seventh to ninth embodiments, the inrush current caused by the feedforward of the no-load voltage at the time of arc ignition and the inrush current caused by the saturation of the proportional integrator of the current feedback system are collectively suppressed. The configuration individually suppresses an inrush current caused by feedforward of a no-load voltage at the time of arc ignition and an inrush current caused by saturation of a proportional integrator of a current feedback system.

FIG. 10 is a configuration diagram of the power supply control device according to the present embodiment. In the present embodiment, a switch 15 is provided between the output unit of the voltage conversion unit 6 and the input unit of the adder 8 in the same manner as in the first embodiment. A switch 18 is provided between the output section of the proportional integrator 9 and the input section of the adder 8 as in the fourth embodiment.

Next, the operation of the present embodiment will be described. The basic operation is the same as in the first and fourth embodiments. Before the arc is ignited and when the arc is broken,
The switches 15 and 18 are switched to the initial value setting means, and the respective initial values are input to the adder 8. The adder 8 outputs a control signal to the phase angle controller 5 to output a gate control signal capable of maintaining the firing phase angle of the switching element at 85 degrees.

By the operation of the switching element, an arc can be fired between the arc furnace electrode 3 and scrap in the arc furnace. Then, when the arc ignition is started, a current flows. Thereafter, the current detection value of the current converter 14 and the voltage detection value of the voltage converter are checked, and the switch is returned from the state where the respective values have become the values equivalent to the initial values, and the control of the arc furnace power supply is performed by the control system. Switch to control by.

Embodiment 11 FIG. In the tenth embodiment, switches 15 and 18 are provided in each control loop, and an initial value is switched and selected in each control loop and input to the adder 8 at the time of arc ignition. The switch 18 of the current feedback loop is replaced with a multiplier.

FIG. 11 is a configuration diagram of a power supply control device according to the present embodiment. In the present embodiment, the switch 18 shown in FIG. 10 is replaced with a multiplier 19, and if it is determined that the current starts flowing after the arc is ignited, the switch 18 is gradually engaged in accordance with the saturation cancellation state of the proportional integrator. By increasing the value in one direction, the current feedback control is gradually restored after switching to the voltage feedforward control.
Other basic operations are the same as in the first and fifth embodiments.

Embodiment 12 FIG. In the eleventh embodiment, the multiplier 19 is provided in the current feedback loop, and the control after arc ignition is gradually switched to the current feedback control. However, in the present embodiment, a limiter is provided instead of the multiplier 19 and the proportional integrator 9. Provide a proportional integrator. FIG. 12 is a configuration diagram of the power supply control device according to the present embodiment. In the present embodiment, the multiplier 19 and the proportional integrator 9 shown in FIG. 11 are replaced by a proportional integrator 20 with a limiter. The current feedback control is gradually restored after switching to the voltage feedforward control by increasing the limit value in accordance with the saturation elimination state of the switch 20. Other basic operations are described in the first and sixth embodiments.
Is the same as

Embodiment 13 FIG. In Embodiment 10 described above, switches 15 and 18 are provided in each control loop, and an initial value is switched and selected in each control loop and input to the adder 8 at the time of arc ignition. However, in this embodiment, a voltage feedforward loop is used. The switch 15 is replaced with a multiplier.

FIG. 13 is a configuration diagram of a power supply control device according to the present embodiment. In the present embodiment, the switch 15 shown in FIG. 10 is replaced by a multiplier 19, and if the occurrence of an arc voltage is determined after the arc is fired, the coefficient value is gradually increased according to the voltage detection value of the voltage conversion unit 6. Is raised in one direction, the voltage feedforward control is restored. As a result, even if the arc voltage at the time of the arc interruption or before the arc ignition becomes too high, the control can be performed with confidence. Other basic operations are the same as in the first and seventh embodiments.

Embodiment 14 FIG. In the tenth embodiment, switches 15 and 18 are provided in each control loop, and an initial value is switched and selected in each control loop and input to the adder 8 when an arc is fired. 15 and 18 are replaced with multipliers. FIG. 14 is a configuration diagram of the power supply control device according to the present embodiment. In this embodiment, the switches 15 and 18 shown in FIG. 10 are replaced by multipliers 16 and 19, respectively. If it is determined that the output of the rectifier 2 has reached the arc control voltage after the arc is ignited, the voltage conversion is performed. The coefficient value is gradually increased in one direction according to the voltage detection value of the unit 6.

When it is determined from the current detection value of the current converter 14 that the current has started to flow, the coefficient value is gradually increased in one direction according to the saturation state elimination state of the proportional integrator 9. As a result, even if the arc voltage becomes too high, the arc power supply control can be performed with confidence. The basic operation is the same as in the first and eighth embodiments.

Embodiment 15 FIG. In the fourteenth embodiment, the multiplier 19 is provided in the current feedback loop. However, in the present embodiment, the multiplier 19 and the proportional integrator 9 are replaced with a proportional integrator 20 with a limiter as shown in FIG. With such a device configuration, the inrush current due to the feedforward of the no-load voltage at the time of arc ignition and the inrush current due to the saturation of the proportional integrator 20 with a limiter are suppressed, and thereafter the limit of the limiter of the proportional integrator 20 with a limiter is gradually reduced. By increasing the value, stable arc firing can be performed. Other basic operations are the same as in the first and ninth embodiments.

Embodiment 16 FIG. In the tenth embodiment, the switch 15 is provided in the voltage feedforward loop. However, in the present embodiment, a limiter 17 is provided instead of the switch 15 as shown in FIG. With such a device configuration, the inrush current due to the feedforward of the no-load voltage at the time of arc ignition and the inrush current due to the saturation of the proportional integrator 20 with a limiter are suppressed, and thereafter the limit value of the limiter 17 is gradually increased. And stable arc ignition can be performed. The other basic operations are described in the second and fourth embodiments.
Is the same as

Embodiment 17 FIG. In the sixteenth embodiment, the switch 18 is provided in the current feedback loop. However, in the present embodiment, a multiplier 17 is provided instead of the switch 18 as shown in FIG. With such a device configuration, the inrush current due to feedforward of the no-load voltage at the time of arc ignition and the inrush current due to saturation of the proportional integrator 20 with a limiter are suppressed, and thereafter, the coefficient value of the multiplier 17 is gradually increased to 1. It is possible to perform a stable arc firing by raising it.
Other basic operations are the same as in the second and fifth embodiments.

Embodiment 18 FIG. In the seventeenth embodiment, the multiplier 17 is provided in the current feedback loop. However, in the present embodiment, the multiplier 17 and the proportional integrator 9 are replaced with a proportional integrator 20 with a limiter as shown in FIG. With such a device configuration, the inrush current due to the feedforward of the no-load voltage at the time of arc ignition and the inrush current due to the saturation of the proportional integrator 20 with a limiter are suppressed, and thereafter the limit of the proportional integrator 20 with a limiter is gradually increased. By doing this, stable arc ignition can be performed. Other basic operations are the same as in the second and sixth embodiments.

Embodiment 19 FIG. Embodiments 10 to 1
In FIG. 19, the inrush current is suppressed by feed-forward of the no-load voltage at the time of arc ignition, and the inrush current is suppressed by the saturation of the integrator 9. In the present embodiment, the voltage feed is suppressed as shown in FIG. As in the first embodiment, a switch 15 is provided at the output section of the voltage conversion section 6 and the input section of the adder 8 as a forward loop, and the output of the adder 8 is a common part of the voltage feedforward loop, the current feedback loop and the loop. The switch 21 is provided in the section and the input section of the phase angle control device 5 as in the seventh embodiment.

According to this configuration, when the switch 15 is operated and the initial value is input to the adder 8 without operating the switch 21, the feedforward of the no-load voltage at the time of arc ignition is performed as in the first embodiment. Rush current due to the above. When the switch 21 is operated without operating the switch 15 and the initial value is input to the phase angle control device 5, as in the seventh embodiment, an inrush current due to feedforward of a no-load voltage at the time of arc ignition, Proportional integrator 9
And the inrush current due to the saturation can be suppressed collectively. Other basic operations are the same as in the second and seventh embodiments.

Embodiment 20 FIG. In the present embodiment, as shown in FIG.
1 is replaced by a multiplier 22 as in the eighth embodiment. According to this configuration, when the coefficient value of the multiplier 22 is set to 1 and the initial value is input to the adder 8 by operating the switch 15, the feedforward of the no-load voltage at the time of arc ignition is performed in the same manner as in the first embodiment. Inrush current can be suppressed.

Further, when the coefficient value of the multiplier 22 is set to 1 or less and the control signal having a value corresponding to the initial value is input to the phase angle control device 5 without operating the switch 15, the arc point The inrush current due to the feedforward of the no-load voltage at the time of arc and the inrush current due to the saturation of the proportional integrator 9 can be suppressed collectively. Other basic operations are the same as in the second and eighth embodiments.

Embodiment 21 FIG. In the present embodiment, as shown in FIG.
Is replaced by a limiter 23 as in the ninth embodiment. According to this configuration, when the limit value of the limiter 23 is maximized and the switch 15 is operated to input the initial value to the adder 8, the inrush by the feedforward of the no-load voltage at the time of arc ignition is performed as in the first embodiment. The current can be suppressed.

Further, when the limit value of the limiter 23 is set to a predetermined value without operating the switch 15 and the value of the control signal from the adder 8 is set to the initial value and input to the phase angle control device 5, the ninth embodiment differs from the ninth embodiment. Similarly, the inrush current due to the feedforward of the no-load voltage at the time of arc ignition and the inrush current due to the saturation of the proportional integrator 9 can be suppressed collectively. Other basic operations are described in the second and ninth embodiments.
Is the same as

Embodiment 22 FIG. In the present embodiment, as shown in FIG.
5 is replaced with a multiplier 16 as in the second embodiment. According to this configuration, when the switch 21 is not operated and the coefficient value of the multiplier 16 is set to 1 or less and a value corresponding to the initial value is input to the adder 8, as in the second embodiment, there is no load at the time of arc ignition. Inrush current due to voltage feedforward can be suppressed.

When the coefficient value of the multiplier 16 is set to 1 and the switch 21 is operated to input the initial value to the phase angle control device 5, the feedforward of the no-load voltage at the time of arc ignition is performed in the same manner as in the seventh embodiment. And the inrush current due to the saturation of the proportional integrator 9 can be suppressed collectively. Other basic operations are the same as in the second and seventh embodiments.

Embodiment 23 FIG. In the present embodiment, as shown in FIG.
1 is replaced by a multiplier 22 as in the eighth embodiment. According to this configuration, when the coefficient value of the multiplier 22 is set to 1 and the coefficient value of the multiplier 16 is set to 1 or less and a value corresponding to the initial value is input to the adder 8, as in the second embodiment, Inrush current due to feedforward of no-load voltage can be suppressed.

When the coefficient value of the multiplier 16 is set to 1 and the coefficient value of the multiplier 22 is set to 1 or less and a value corresponding to the initial value is input to the phase angle control device 5, the arc ignition is performed in the same manner as in the eighth embodiment. Inrush current due to feed-forward of no-load voltage at the time and inrush current due to saturation of the proportional integrator 9 can be suppressed collectively. Other basic operations are the same as in the second and eighth embodiments.

Embodiment 24 FIG. In the present embodiment, as shown in FIG.
1 is replaced with a limiter 23 as in the ninth embodiment. According to this configuration, when the limit value of the limiter 23 is maximized, the coefficient value of the multiplier 16 is set to 1 or less, and a value corresponding to the initial value is input to the adder 8, as in the second embodiment, An inrush current due to load voltage feedforward can be suppressed.

When the coefficient value of the multiplier 16 is set to 1, the limit value of the limiter 23 is set to a predetermined value, and a value corresponding to the initial value is input to the phase angle control device 5, the same as in the ninth embodiment, And the inrush current due to feed-forward of the no-load voltage and the inrush current due to saturation of the proportional integrator 9 can be collectively suppressed. For other basic actions,
This is similar to the second and ninth embodiments.

Embodiment 25 FIG. In the present embodiment, as shown in FIG.
6 is replaced with a limiter 17 as in the third embodiment. According to this configuration, when the limit value of the limiter 17 is set to a predetermined value and the value corresponding to the initial value is input to the adder 8 without operating the switch 21, the no-load voltage at the time of arc ignition is set as in the second embodiment. Inrush current due to feedforward can be suppressed.

Further, the limit value of the limiter 17 is maximized,
When the switch 21 is operated to input an initial value to the phase angle control device 5, as in the first embodiment, an inrush current due to feedforward of a no-load voltage at the time of arc ignition and an inrush current due to saturation of the proportional integrator 9. Can be suppressed collectively. Other basic operations are the same as those in the third and seventh embodiments.

Embodiment 26 FIG. In the present embodiment, as shown in FIG.
1 is replaced by a multiplier 22 as in the eighth embodiment. According to this configuration, when the coefficient value of the multiplier 22 is set to 1, the limit value of the limiter 17 is set to a predetermined value, and a value equivalent to the initial value is input to the adder 8, the same as in the third embodiment, An inrush current due to load voltage feedforward can be suppressed.

Further, the limit value of the limiter 17 is maximized,
When the coefficient value of the multiplier 22 is set to 1 or less and a control signal having a value equivalent to the initial value is input to the phase angle control device 5, as in the ninth embodiment, an inrush current due to feedforward of a no-load voltage at the time of arc ignition is performed. And the inrush current due to the saturation of the proportional integrator 9 can be suppressed collectively. Other basic operations are the same as in the eighth and ninth embodiments.

Embodiment 27 FIG. In the present embodiment, as shown in FIG.
Is replaced by a limiter 23 as in the ninth embodiment. According to this configuration, when the limit value of the limiter 23 is maximized, the limit value of the limiter 17 is set to a predetermined value, and a value corresponding to the initial value is input to the adder 8, the same as in the third embodiment, Inrush current due to voltage feedforward can be suppressed.

The limit value of the limiter 17 is maximized,
When the limit value of the limiter 23 is set to a predetermined value and a control signal having a value equivalent to the initial value is input to the phase angle control device 5, as in the ninth embodiment, the inrush current due to the feedforward of the no-load voltage at the time of arc ignition is reduced. Inrush current due to saturation of the proportional integrator 9 can be suppressed collectively. Other basic operations are the same as those in the third and ninth embodiments.

Embodiment 28 FIG. In the present embodiment, in addition to the configuration of the tenth embodiment shown in FIG. 28, inrush current due to feed-forward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. Switch 21 as in the configuration of the seventh embodiment.
Is provided.

As a result, the rush current due to the feedforward of the no-load voltage and the rush current due to the saturation of the proportional integrator can be suppressed by the switch 21 at a time.
The switch 18 and 15 are selectively operated in a state where the switch 21 is made inoperative and the control signal from the adder 8 is input to the phase angle controller 5 without changing the value. Power supply control can be switched between current feedback control and voltage feedforward control.

Embodiment 29 FIG. In the present embodiment, in addition to the configuration of the tenth embodiment shown in FIG. 29, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. A multiplier 8 is provided in the same manner as in the configuration of the eighth embodiment so as to be able to perform the following.

As a result, the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator can be collectively suppressed by the multiplier 22. The switches 18 and 15 are selectively operated while the coefficient value of the multiplier 22 is controlled such that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value. Can be switched between current feedback control and voltage feedforward control.

Embodiment 30 FIG. In the present embodiment, in addition to the configuration of the tenth embodiment shown in FIG. 30, inrush current due to feed-forward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. In the same manner as in the ninth embodiment, the limiter 23
Is provided.

As a result, the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator can be collectively suppressed by the limiter 23.
In addition, the switches 18 and 15 are selectively operated in a state where the limit value of the limiter 23 is controlled so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value. Can be switched between current feedback control and voltage feedforward control. In addition, if the limiter 23 is used together with each control, the amount of current feedback or the amount of voltage feedforward can be finally controlled.

Embodiment 31 FIG. In the present embodiment, in addition to the configuration of the eleventh embodiment shown in FIG. 31, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. Switch 21 as in the configuration of the seventh embodiment.
Is provided.

As a result, the rush current due to the feed-forward of the no-load voltage and the rush current due to the saturation of the proportional integrator can be collectively suppressed by the switch 21.
The presence or absence of the voltage feedforward amount when the switch 15 is switched with the switch 21 switched to the adder 8 so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value. By adjusting the coefficient value of the multiplier 19 according to the above, the sum of the current feedback amount and the voltage feedforward amount by the adder 8 can be changed to an appropriate value.

Embodiment 32 FIG. In the present embodiment, in addition to the configuration of the eleventh embodiment shown in FIG. 32, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. A multiplier 22 is provided in the same manner as in the configuration of the eighth embodiment so as to be able to perform the following.

As a result, the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator can be suppressed by the multiplier 22 at a time. Further, in a state where the coefficient value is controlled so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the multiplication is performed according to the presence or absence of the voltage feedforward amount when the switch 15 is switched. By adjusting the coefficient value of the unit 19,
The sum of the amount of current feedback and the amount of voltage feedforward by the adder 8 can be changed to an appropriate value.

Embodiment 33 FIG. In the present embodiment, in addition to the configuration of the eleventh embodiment shown in FIG. 33, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. In the same manner as in the ninth embodiment, the limiter 23
Is provided.

As a result, the limiter 23 can collectively suppress the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator.
Further, in a state where the limit value is controlled so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the control signal is adjusted according to the presence or absence of the voltage feedforward amount when the switch 15 is switched. By adjusting the coefficient value of the multiplier 19, the sum of the current feedback amount and the voltage feedforward amount by the adder 8 can be changed to an appropriate value.

Embodiment 34 FIG. In the present embodiment, in addition to the configuration of the twelfth embodiment shown in FIG. 34, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. In this embodiment, a switch 21 is provided in the same manner as in the configuration of the seventh embodiment.

As a result, the rush current due to the feed-forward of the no-load voltage and the rush current due to the saturation of the proportional integrator can be collectively suppressed by the switch 21.
The presence or absence of the voltage feedforward amount when the switch 15 is switched with the switch 21 switched to the adder 8 side so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value. Limiter integrator 2 according to
By adjusting the limit value of 0, the sum of the amount of current feedback and the amount of voltage feedforward by the adder 8 can be changed to an appropriate value.

Embodiment 35 FIG. In the present embodiment, in addition to the configuration of the twelfth embodiment shown in FIG. 35, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. A multiplier 22 is provided in the same manner as in the configuration of the eighth embodiment so as to be able to perform the following.

As a result, the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator can be collectively suppressed by the multiplier 22. Further, with the coefficient value adjusted so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the limiter integration is performed according to the presence or absence of the voltage feedforward amount when the switch 15 is switched. By adjusting the limit value of the adder 20, the sum of the current feedback amount and the voltage feedforward amount by the adder 8 can be changed to an appropriate value.

Embodiment 36 FIG. In the present embodiment, in addition to the configuration of the twelfth embodiment shown in FIG. 36, inrush current due to feed-forward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. In the same manner as in the ninth embodiment, the limiter 23
Is provided.

As a result, the limiter 23 can suppress the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator.
In a state where the limit value is adjusted so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the limiter integration is performed according to the presence or absence of the voltage feedforward amount when the switch 15 is switched. By adjusting the limit value of the adder 20, the sum of the current feedback amount and the voltage feedforward amount by the adder 8 can be changed to an appropriate value.

Embodiment 37 FIG. In the present embodiment, in addition to the configuration of the thirteenth embodiment shown in FIG. 37, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. Switch 21 as in the configuration of the seventh embodiment.
Is provided.

As a result, the rush current due to the feedforward of the no-load voltage and the rush current due to the saturation of the proportional integrator can be collectively suppressed by the switch 21.
When the switch 21 is switched to the adder 8 so that the control signal from the adder 8 is input to the phase angle controller 5 without changing the value, the presence or absence of the current feedback amount when the switch 18 is switched is determined. By adjusting the coefficient value of the multiplier 16 at the same time, the sum of the current feedback amount and the voltage feedforward amount by the adder 8 can be changed to an appropriate value.

Embodiment 38 FIG. In the present embodiment, in addition to the configuration of the thirteenth embodiment shown in FIG. 38, inrush current due to feed-forward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. A multiplier 22 is provided in the same manner as in the configuration of the eighth embodiment so as to be able to perform the following.

As a result, the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator can be collectively suppressed by the multiplier 22. Further, in a state where the coefficient value of the multiplier 22 is controlled so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the presence or absence of the current feedback amount when the switch 18 is switched is determined. By adjusting the coefficient value of the multiplier 16 at the same time, the sum of the current feedback amount and the voltage feedforward amount by the adder 8 can be changed to an appropriate value.

Embodiment 39 FIG. In the present embodiment, in addition to the configuration of the thirteenth embodiment shown in FIG. 39, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. In the same manner as the configuration of the ninth embodiment,
Is provided.

As a result, the limiter 22 can suppress the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator.
Further, in a state where the limit value of the limiter 22 is controlled so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the current feedback amount when the switch 18 is switched is adjusted according to the presence or absence of the current feedback amount. By adjusting the coefficient value of the multiplier 16 by multiplication, the sum of the current feedback amount and the voltage feedforward amount by the adder 8 can be changed to an appropriate value.

Embodiment 40 FIG. In the present embodiment, in addition to the configuration of the fourteenth embodiment shown in FIG. 40, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. Switch 21 as in the configuration of the seventh embodiment.
Is provided.

As a result, the rush current due to the feed-forward of the no-load voltage and the rush current due to the saturation of the proportional integrator can be collectively suppressed by the switch 21.
Further, in a state where the switch 21 is switched to the adder 8 side so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the coefficient values of the multipliers 16 and 19 are adjusted in association with each other. Thus, the ratio between the current feedback control and the voltage feedforward control for the arc power supply can be changed, and fine control can be performed.

Embodiment 41 FIG. In the present embodiment, in addition to the configuration of the fourteenth embodiment shown in FIG. 41, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. A multiplier 8 is provided in the same manner as in the configuration of the eighth embodiment so as to be able to perform the following.

As a result, the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator can be collectively suppressed by the multiplier 22. Further, in a state where the coefficient value of the multiplier 22 is controlled so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the coefficient values of the multipliers 16 and 19 are adjusted in association with each other. By changing the ratio of the current feedback control and the voltage feedforward control to the arc power supply, fine control can be performed.

Embodiment 42 FIG. In this embodiment, in addition to the configuration of the fourteenth embodiment shown in FIG. 42, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. In the same manner as in the ninth embodiment, the limiter 23
Is provided.

As a result, the limiter 23 can suppress the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator at once.
Also, by controlling the limit value of the limiter 23 so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the coefficient values of the multipliers 16 and 19 are adjusted in association with each other. Fine control can be performed by changing the ratio between the current feedback control and the voltage feedforward control with respect to the arc power supply.

Embodiment 43 FIG. In the present embodiment, in addition to the configuration of the fifteenth embodiment shown in FIG. 43, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. Switch 21 as in the configuration of the seventh embodiment.
Is provided.

As a result, the rush current due to the feed-forward of the no-load voltage and the rush current due to the saturation of the proportional integrator can be collectively suppressed by the switch 21.
In a state where the switch 21 is switched to the adder 8 side so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the coefficient of the multiplier 16 and the proportional integrator 20 with the limiter are changed. By gradually increasing the limit value, stable arc ignition can be performed. Transformer 1
Multiplier 1 connected to the output of the voltage converter 6 in accordance with the voltage appearing on the secondary terminal of the transformer 1 when the tap position of the
By changing the coefficient value of No. 6, the voltage feedforward amount can be changed.

Embodiment 44 FIG. In the present embodiment, in addition to the configuration of the fifteenth embodiment shown in FIG. 44, inrush current due to feed-forward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. A multiplier 22 is provided in the same manner as in the configuration of the eighth embodiment so as to be able to perform the following.

As a result, the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator can be collectively suppressed by the multiplier 22.
Further, the coefficient of the multiplier 16 and the proportional integrator with limiter are controlled in a state where the coefficient value of the multiplier 22 is controlled to 1 so that the control signal from the adder 8 is input to the phase angle controller 5 without changing the value. By gradually increasing the limit value of 20, it is possible to perform stable arc ignition. Transformer 1
Multiplier 1 connected to the output of the voltage converter 6 in accordance with the voltage appearing on the secondary terminal of the transformer 1 when the tap position of the
By changing the coefficient value of No. 6, the voltage feedforward amount can be changed.

Embodiment 45 FIG. In the present embodiment, in addition to the configuration of the fifteenth embodiment shown in FIG. 45, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. In the same manner as in the configuration of the seventh embodiment,
Is provided.

As a result, the limiter 23 can suppress the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator at once.
In a state where the value of the limiter 23 is controlled so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the coefficient of the multiplier 16 and the proportional integrator 2 with the limiter are controlled.
By gradually increasing the limit value of 0, stable arc firing can be performed. Further, by changing the coefficient value of the multiplier 16 connected to the output of the voltage conversion unit 6 according to the voltage appearing at the secondary terminal of the transformer 1 when the tap position of the transformer 1 is changed, the voltage feedforward is performed. Be able to change the amount.

Embodiment 46 FIG. In the present embodiment, in addition to the configuration of the sixteenth embodiment shown in FIG. 46, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of proportional integrator 9 are collectively suppressed. Switch 2 in the same manner as in the configuration of the seventh embodiment.
1 is provided.

As a result, the rush current due to the feed-forward of the no-load voltage and the rush current due to the saturation of the proportional integrator can be collectively suppressed by the switch 21.
The limit value of the limiter 17 is gradually increased while the switch 21 is switched to the adder 8 so that the control signal from the adder 8 is input to the phase angle controller 5 without changing the value. This makes it possible to suppress an inrush current due to feedforward of a no-load voltage at the time of arc ignition. Further, the switch 18 is switched to the initial value setting means before the arc is cut or the arc is ignited, and the rush current due to the saturation of the proportional integrator 9 is suppressed by switching the switch 18 to the output of the proportional integrator 9 after the arc is stabilized. be able to.

Embodiment 47 FIG. In the present embodiment, in addition to the configuration of the sixteenth embodiment shown in FIG. 47, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of a proportional integrator are collectively suppressed. A multiplier 22 is provided in the same manner as in the configuration of the eighth embodiment so as to be able to perform the following.

As a result, the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator can be collectively suppressed by the multiplier 22. The limit value of the limiter 17 is gradually increased while the coefficient value of the multiplier 22 is controlled to 1 so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value. Thus, the inrush current due to the feedforward of the no-load voltage at the time of arc ignition can be suppressed. Further, the switch 18 is switched to the initial value setting means before the arc is cut or the arc is ignited, and the rush current due to the saturation of the proportional integrator 9 is suppressed by switching the switch 18 to the output of the proportional integrator 9 after the arc is stabilized. be able to.

Embodiment 48 FIG. In the present embodiment, in addition to the configuration of the sixteenth embodiment shown in FIG. 48, inrush current due to feedforward of no-load voltage during arc ignition and inrush current due to saturation of proportional integrator 9 are collectively suppressed. As in the case of the ninth embodiment, the limiter 2
8 is provided.

As a result, the inrush current due to the feedforward of the no-load voltage by the limiter 25 and the proportional integrator 9
Rush current due to the saturation of the semiconductor device can be collectively suppressed. In addition, while the limit value of the limiter 28 is controlled so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the limit value of the limiter 17 is gradually increased, so that the arc is increased. Inrush current due to feed-forward of no-load voltage at the time of ignition can be suppressed. In addition, arc break,
By switching the switch 18 to the initial value setting means before the arc is ignited, and by switching the switch 18 to the output of the proportional integrator 9 after the arc is stabilized, the rush current due to the saturation of the proportional integrator 9 can be suppressed.

Embodiment 49 FIG. In the present embodiment, in addition to the configuration of the seventeenth embodiment shown in FIG. 49, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of proportional integrator 9 are collectively suppressed. Switch 2 in the same manner as in the configuration of the seventh embodiment.
1 is provided.

As a result, the inrush current due to the feedforward of the no-load voltage and the proportional integrator 9
Rush current due to the saturation of the semiconductor device can be collectively suppressed. Further, with the switch 21 switched to the adder 8 so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the limit value of the limiter 17 and the multiplier 19
The inrush current due to the feed-forward of the no-load voltage at the time of arc ignition and the inrush current due to the saturation of the proportional integrator 9 can be suppressed by gradually increasing the coefficient value of.

Embodiment 50 FIG. In the present embodiment, in addition to the configuration of the seventeenth embodiment shown in FIG. 50, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of proportional integrator 9 are collectively suppressed. The multiplier 22 has the same configuration as that of the seventh embodiment.
Is provided.

As a result, the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator can be collectively suppressed by the multiplier 22. In a state where the coefficient value of the multiplier 22 is controlled so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the limit value of the limiter 17 and the coefficient value of the multiplier 19 are controlled. Is gradually increased, it is possible to suppress an inrush current due to feedforward of a no-load voltage at the time of arc ignition and an inrush current due to saturation of the proportional integrator 9.

Embodiment 51 FIG. In the present embodiment, in addition to the configuration of the seventeenth embodiment shown in FIG. 51, inrush current due to feed-forward of no-load voltage at the time of arc ignition and inrush current due to saturation of proportional integrator 9 are collectively suppressed. As in the case of the ninth embodiment, the limiter 2
3 is provided.

As a result, the inrush current due to the feedforward of the no-load voltage by the limiter 23 and the proportional integrator 9
Rush current due to the saturation of the semiconductor device can be collectively suppressed. In a state where the limit value of the limiter 23 is controlled so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, the limit value of the limiter 17 and the coefficient value of the multiplier 19 are changed. By gradually increasing the current, it is possible to suppress an inrush current due to feedforward of a no-load voltage at the time of arc ignition and an inrush current due to saturation of the proportional integrator 9.

Embodiment 52 FIG. In the present embodiment, in addition to the configuration of the eighteenth embodiment shown in FIG. 52, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of proportional integrator 20 with limiter are collectively obtained. The switch 21 is provided in the same manner as in the configuration of the seventh embodiment so as to suppress it.

As a result, the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator 20 with the limiter can be suppressed collectively.
The limit value of the limiter 17 is gradually increased while the switch 21 is switched to the adder 8 so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value. Can stably fire the arc. Also,
Limit value of limiter 17 and proportional integrator 20 with limiter
Is set, and the sum of the maximum value of the voltage feedforward amount and the maximum value of the current feedback amount by the adder 8 is kept constant, so that stable arc ignition can be performed even when the arc voltage becomes too high.

Embodiment 53 FIG. In the present embodiment, in addition to the configuration of the eighteenth embodiment shown in FIG. 53, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of proportional integrator 20 with limiter are collectively obtained. The multiplier 22 is provided in the same manner as in the configuration of the eighth embodiment so as to be able to suppress it.

As a result, the inrush current due to the feed-forward of the no-load voltage and the inrush current due to the saturation of the proportional integrator can be collectively suppressed by the multiplier 22. In addition, the control value of the multiplier 22 is controlled so that the control signal from the adder 8 is input to the phase angle control device 5 without changing the value, and the limit value of the mixer 17 is gradually increased to stabilize. Arc firing can be performed. Further, the limit value of the limiter 17 and the limit value of the proportional integrator 20 with a limiter are set, and the arc voltage becomes too high by keeping the sum of the maximum value of the voltage feedforward amount and the maximum value of the current feedback amount by the adder 8 constant. In this case, stable arc ignition can be performed.

Embodiment 54 FIG. In the present embodiment, in addition to the configuration of the eighteenth embodiment shown in FIG. 54, inrush current due to feedforward of no-load voltage at the time of arc ignition and inrush current due to saturation of proportional integrator 20 with limiter are collectively obtained. A limiter 23 is provided in the same manner as in the configuration of the seventh embodiment so as to suppress it.

As a result, the inrush current due to the feedforward of the no-load voltage and the inrush current due to the saturation of the proportional integrator 20 with the limiter can be collectively suppressed by the limiter 23. Also, the limiter 23 is controlled so that the control signal from the adder 8 is input to the phase angle controller 5 without changing the value.
In the state where the limit value is controlled, a stable arc firing can be performed by gradually increasing the limit value of the emitter 17. Further, the limit value of the limiter 17 and the limit value of the proportional integrator 20 with a limiter are set, and the arc voltage becomes too high by keeping the sum of the maximum value of the voltage feedforward amount and the maximum value of the current feedback amount by the adder 8 constant. In this case, stable arc ignition can be performed.

Embodiment 55 FIG. Embodiments 28 to 5 above
4 is a limiter 2 for each of the outputs of the adder 8 common to both the voltage feedforward system, the current feedback system, and both the voltage feedforward system and the current feedback system.
3. Inrush current suppression means including a multiplier 22 or a switch 21 is provided. In the present embodiment, a switch 18 is provided in a current feedback system as shown in FIG. Provide.

As a result, the rush current due to the no-load voltage at the time of arc ignition can be suppressed by controlling the switch 21, and the rush current due to the saturation of the proportional integrator 9 can be suppressed by controlling the switch 18.

Embodiment 56 FIG. In this embodiment, as shown in FIG. 56, the switch 18 is provided in the current feedback system, and the multiplier 22 is provided in the output of the adder 8. As a result,
The rush current due to the no-load voltage at the time of arc ignition can be suppressed by controlling the multiplier 22, and the rush current due to the saturation of the proportional integrator 9 can be suppressed by controlling the switch 18. Further, by gradually increasing the coefficient value of the multiplier 22, stable arc ignition can be performed.

Embodiment 57 FIG. In this embodiment, as shown in FIG. 57, a switch 18 is provided in the current feedback system, and a limiter 23 is provided in the output of the adder 8. As a result, by controlling the limit value of the limiter 23, the inrush current due to the no-load voltage at the time of arc ignition is suppressed, and the switch 18
Can suppress the inrush current due to the saturation of the proportional integrator 9. Further, by gradually increasing the limit value of the limiter 23, stable arc firing can be performed.

Embodiment 58 FIG. In the present embodiment, a multiplier 19 is provided in the current feedback system as shown in FIG.
A switch 21 is provided at the output of the adder 8. As a result, the inrush current due to the no-load voltage at the time of arc firing can be suppressed by controlling the coefficient value of the multiplier 19, and the inrush current due to saturation of the proportional integrator 9 can be suppressed by controlling the switch 21. Further, by gradually increasing the coefficient value of the multiplier 19, stable arc ignition can be performed.

Embodiment 59 FIG. In this embodiment, a multiplier 19 is provided in a current feedback system as shown in FIG.
A multiplier 22 is provided at the output of the adder 8. As a result, the inrush current due to no-load voltage at the time of arc ignition is suppressed by controlling the coefficient value of the multiplier 22, and the inrush current due to saturation of the proportional integrator 9 is controlled by controlling the coefficient value of the multiplier 19. Can be. Further, by gradually increasing the coefficient values of the multipliers 19 and 22, stable arc ignition can be performed.

Embodiment 60 FIG. In this embodiment, a multiplier 19 is provided in a current feedback system as shown in FIG.
A limiter 28 is provided at the output of the adder 8. As a result, by controlling the limit value of the limiter 28, it is possible to suppress the rush current due to the no-load voltage at the time of arc ignition, and to control the rush current due to the saturation of the proportional integrator 9 by controlling the coefficient value of the multiplier 19. it can. Further, by gradually increasing the limit value of the limiter 28 and the coefficient value of the multiplier 19, stable arc ignition can be performed.

Embodiment 61 FIG. In this embodiment, as shown in FIG. 61, a proportional integrator 20 with a limiter is provided in the current feedback system, and a switch 21 is provided at the output of the adder 8. As a result, the rush current due to the no-load voltage at the time of arc ignition is suppressed by controlling the switch 21, and the rush current due to saturation of the proportional integrator 20 with the limiter is controlled by controlling the limit value of the proportional integrator 20 with the limiter. be able to. Further, by gradually increasing the limit value of the proportional integrator 20 with a limiter, stable arc ignition can be performed.

Embodiment 62 FIG. In this embodiment, as shown in FIG. 62, a proportional integrator 20 with a limiter is provided in the current feedback system, and a multiplier 22 is provided at the output of the adder 8.
As a result, the inrush current due to no-load voltage at the time of arc ignition is suppressed by controlling the coefficient value of the multiplier 22, and the inrush current due to saturation of the proportional integrator 20 with limiter is controlled by controlling the limit value of the proportional integrator 20 with limiter. The current can be suppressed. Further, by gradually increasing the limit value of the proportional integrator with limiter 20 and the coefficient value of the multiplier 22, stable arc ignition can be performed.

Embodiment 63 FIG. In the present embodiment, as shown in FIG. 63, a proportional integrator 20 with a limiter is provided in the current feedback system, and a limiter 23 is provided in the output of the adder 8. As a result, by controlling the limit value of the limiter 23, the inrush current due to no-load voltage at the time of arc ignition is suppressed, and by controlling the limit value of the proportional integrator 20 with limiter, the inrush current due to saturation of the proportional integrator 20 with limiter is controlled. Can be suppressed. Further, by gradually increasing the limit value of the proportional integrator 20 with limiter and the limit value of the limiter 23, stable arc ignition can be performed.

[0186]

According to the first aspect of the present invention, a deviation between a load current flowing through a switching element type rectifier for supplying DC power to a load and a preset load current is proportionally integrated, and the deviation is calculated based on the deviation. Current feedback control means including a proportional integrator for generating a control signal and outputting the control signal to the rectifier; detecting a voltage related to the load, and responding to the control signal according to the load voltage so as to follow the load voltage; Voltage feedforward control means for inputting the added output obtained by adding the voltage feedforward output in the adder to the rectifier, and limiting a control signal to be output to the rectifier when the load is turned on again after the load is cut off. Since the control signal limiting means is provided, there is an effect that an inrush current flowing through the rectifier at the time of reloading the load can be suppressed.

According to the second aspect of the present invention, the control signal limiting means limits at least one of the output signal of the proportional integrator of the current feedback control means, the voltage feedforward output and the addition output. There is an effect that an inrush current flowing through the rectifier at the time of closing can be suppressed.

According to the third aspect of the present invention, the control signal limiting means for limiting the voltage feedforward output switches the input to the adder from the voltage feedforward output to an initial value of a predetermined level when the load is turned on again. Since the first switch is used, the rush current at the time of reloading the load due to the feedforward of the no-load voltage can be suppressed with a simple configuration.

According to the fourth aspect of the present invention, the control signal limiting means for limiting the voltage feed-forward output multiplies the voltage feed-forward output at the time of reloading the load by a predetermined coefficient value to obtain an initial value of a predetermined level. The multiplier is configured to input the signal to the adder and increase the coefficient value to 1 after the load is applied. Therefore, it is possible to suppress the rush current at the time of reloading the load by feed forward of the no-load voltage, and to increase the coefficient value of the multiplier. There is an effect that the load can be operated stably by gradually increasing the load.

According to the fifth aspect of the present invention, the control signal limiting means for limiting the voltage feedforward output limits the voltage feedforward performed at the time of reloading the load to a constant value and inputs the voltage feedforward to the adder. Is configured with a limiter that increases the limit value, so it is possible to suppress the rush current when the load is re-input by feedforward of no-load voltage, and to operate the load stably by gradually increasing the limit value of the limiter. There is an effect that can be.

According to the invention of claim 6, the control signal limiting means for limiting the output signal of the proportional integrator switches the input to the adder to the initial value of the predetermined level from the output signal when the load is turned on again. Therefore, the inrush current at the time of reloading the load, which occurs when the proportional integrator is saturated when no current is flowing, can be suppressed.

According to the seventh aspect of the present invention, the control signal limiting means for limiting the output signal of the proportional integrator is added to the output signal by multiplying the output signal by a predetermined coefficient value to obtain an initial value of a predetermined level when the load is turned on again. Since the multiplier is configured to multiply the coefficient value by 1 after inputting the load to the unit and increasing the coefficient value, it is possible to suppress the inrush current at the time of reloading the load caused by the saturation of the proportional integrator when no current is flowing. In addition, the load can be operated stably by gradually increasing the coefficient value of the multiplier.

According to the eighth aspect of the present invention, the proportional integrator includes a limiter for limiting the output signal to constitute control signal limiting means, and when the load is turned on again, the limiter limits the output signal to a constant value. Since the limit value of the limiter is increased after the load is applied,
In addition to suppressing the inrush current at the time of reloading the load, which occurs when the proportional integrator saturates when no current is flowing, the load can be operated stably by gradually increasing the limit value of the limiter. is there.

According to the ninth aspect of the present invention, the control signal limiting means for limiting the added output is a third switch for switching the input to the rectifier at the time of reloading the load and switching the added output to an initial value of a predetermined level. With this configuration, the inrush current at the time of reloading the load due to saturation of the proportional integrator when no current is flowing and the inrush current at the time of reloading the load by feedforward of no-load voltage are combined in a simple device configuration. The effect is that it can be suppressed.

According to the tenth aspect of the present invention, the control signal limiting means for limiting the added output of the output signal of the proportional integrator and the voltage feedforward output is provided to the added output input to the rectifier at the time of reloading the load. The multiplication means is configured to multiply the coefficient value to obtain an initial value of a predetermined level, and to increase the coefficient value to 1 after the load is applied. Inrush current at the time of closing and inrush current at the time of reloading the load by feedforward of no-load voltage can be suppressed collectively, and the load can be operated stably by gradually increasing the coefficient value of the multiplier. This has the effect.

According to the eleventh aspect of the present invention, the control signal limiting means for limiting the added output limits the added output input to the rectifier to a constant value when the load is turned on again, and sets the limit value after the load is turned on. Since the current limiter is configured to increase, the inrush current at the time of reloading the load due to saturation of the proportional integrator when no current is flowing and the inrush current at the time of load reloading by feed forward of no-load voltage are collected together. It is possible to operate the load stably by gradually increasing the coefficient value of the multiplier, and to prevent time-limited overcurrent by gradually controlling the control signal of the rectifier. effective.

According to the twelfth aspect of the present invention, each of the voltage feedforward output and the control signal limiting means for limiting the output of the proportional integrator is controlled so that the input to the adder is determined from the voltage feedforward output when the load is turned on again. Since a first switch for switching to an initial value of the level and a second switch for switching to an initial value of a predetermined level from the output of the proportional integrator when the load is re-input, the input to the adding section is constituted by a voltage switch. Since it is possible to switch between the forward control and the current feedback control, there is an effect that optimal control according to the state of the load can be performed.

According to the thirteenth aspect, since at least one of the switches is replaced by a multiplier, the coefficient value of the multiplier is adjusted in accordance with the presence or absence of the voltage feedforward amount or the current feedback amount. In addition, there is an effect that the sum of the voltage feedforward amount or the current feedback amount can be changed to an optimum value. Alternatively, there is an effect that the ratio between the voltage feedforward control and the current feedback control can be changed by controlling the coefficient values of the multipliers in association with each other.

According to the fourteenth aspect, since at least one of the switches is replaced by a limiter,
By changing the limit value of the limiter in accordance with the output voltage of the rectifier, the sum of the maximum value of the current feedback and the voltage feedforward can be kept constant and the control can be performed safely even when the load voltage becomes too high.

According to the fifteenth aspect of the present invention, one of the switches is replaced by a limiter and the other is replaced by a multiplier. Therefore, when a current is not flowing, the load of the load caused by the saturation of the proportional integrator is reduced. The inrush current at the time of closing and the inrush current at the time of reloading the load due to feedforward of no-load voltage can be suppressed collectively, and the limit value of the limiter and the coefficient value of the multiplier can be increased to stabilize the load. It has the effect of being able to operate.

According to the sixteenth aspect, each of the control signal limiting means for limiting the voltage feedforward output and the addition output is switched from the voltage feedforward output to an initial value of a predetermined level when the load is turned on again. And the third switch for switching and inputting the added output to an initial value of a predetermined level when the load is turned on again. Therefore, when the current is not flowing, the proportional integrator is saturated and the inrush occurs when the load is turned on again. Inrush current at the time of reloading the load by feedforward of current and no-load voltage can be suppressed collectively, and it is safe even when the load voltage becomes too high by keeping the sum of the maximum values of current feedback and voltage feedforward constant. There is an effect that can be controlled.

According to the seventeenth aspect of the present invention, at least one of the switches is replaced by a multiplier, so that when the current is not flowing, the proportional integrator is saturated and the inrush at the time of reloading the load occurs. The current and the inrush current at the time of reloading the load by feedforward of the no-load voltage can be suppressed collectively, and the load can be operated stably by gradually increasing the coefficient value of each multiplier.

According to the eighteenth aspect of the present invention, at least one of the switches is replaced with a limiter.
The inrush current at the time of reloading the load due to saturation of the proportional integrator when no current is flowing and the inrush current at the time of load reloading due to no-load voltage feedforward can be suppressed collectively and the limiter limit value By gradually increasing the load, there is an effect that the load can be operated stably.

According to the nineteenth aspect of the present invention, one of the switches is replaced by a limiter and the other is replaced by a multiplier, so that when a current is not flowing, the load of the load caused by the saturation of the proportional integrator is reduced. Inrush current at the time of closing and inrush current at the time of reloading the load by feedforward of no-load voltage can be suppressed collectively, and the load is stabilized by gradually increasing the limiter limit value and multiplier coefficient value. It has the effect of being able to operate.

According to the twentieth aspect, each of the control signal limiting means for limiting the voltage feedforward output, the addition output, and the output of the proportional integrator is replaced with an initial value of a predetermined level from the voltage feedforward output when the load is turned on again. And a third switch for switching and inputting the added output to an initial value of a predetermined level when the load is turned on again.
And the second switch for switching the output of the proportional integrator to an initial value of a predetermined level when the load is turned on again, so that when the current is not flowing, the proportional integrator is saturated and the load is turned on again. The inrush current at the time and the inrush current at the time of reloading the load by the feedforward of the no-load voltage can be suppressed collectively, and the switching between the current feedback control and the voltage feedforward control becomes easy.

According to the twenty-first aspect of the present invention, at least one of the switches is replaced by a multiplier, so that when the current is not flowing, the proportional integrator is saturated and the inrush at the time of reloading the load occurs. The current and the inrush current at the time of reloading the load by feedforward of the no-load voltage can be suppressed collectively, and the load can be operated stably by gradually increasing the coefficient value of the multiplier.

According to the twenty-second aspect, at least one of the switches is replaced with a limiter.
The inrush current at the time of reloading the load due to saturation of the proportional integrator when no current is flowing and the inrush current at the time of load reloading due to no-load voltage feedforward can be suppressed collectively and the limiter limit value By gradually increasing the load, there is an effect that the load can be operated stably.

According to the twenty-third aspect of the present invention, since two of the switches are replaced by multipliers and one is replaced by a limiter, the proportional integrator is saturated when no current flows. The inrush current at the time of load reload and the inrush current at the time of load reload by feedforward of no-load voltage can be suppressed collectively, and the load can be operated stably by increasing the coefficient value of the multiplier. This has the effect.

According to the twenty-fourth aspect, since two of the switches are replaced by limiters and one is replaced by a multiplier, the proportional integrator saturates when no current flows. The inrush current that occurs when the load is restarted and the inrush current that occurs when the load is restarted due to the feed-forward of no-load voltage can be suppressed collectively, and the load can be operated stably by increasing the limit value of the limiter. effective.
Further, there is an effect that the sum of the maximum values of the current feedback and the voltage feedforward is kept constant, and even when the load voltage becomes too high, the control can be performed safely.

According to the twenty-fifth aspect, since one of the two switches is replaced by a limiter and one is replaced by a multiplier, the proportional integrator is saturated when no current flows. The inrush current at the time of reloading the load and the inrush current at the time of reloading the load by feedforward of the no-load voltage can be suppressed collectively, and the load value can be stabilized by increasing the multiplier coefficient value. It has the effect of being able to operate. Further, there is an effect that the sum of the maximum values of the current feedback and the voltage feedforward is kept constant, and even when the load voltage becomes too high, the control can be performed safely.

According to the twenty-sixth aspect, each of the control signal limiting means for limiting the addition output and the output of the proportional integrator switches and inputs the addition output to an initial value of a predetermined level when the load is turned on again. And the second switch for switching the output of the proportional integrator to an initial value of a predetermined level when the load is turned on again, so that when the current is not flowing, the proportional integrator is saturated and the load is turned on again. The inrush current at the time and the inrush current at the time of reloading the load by feedforward of the no-load voltage can be collectively suppressed. Further, there is an effect that the sum of the maximum values of the current feedback and the voltage feedforward is kept constant, and even when the load voltage becomes too high, the control can be performed safely.

According to the twenty-seventh aspect of the present invention, at least one of the switches is replaced by a multiplier, so that the proportional integrator is saturated when no current is flowing and the inrush at the time of reloading the load occurs. The inrush current at the time of reloading the load due to the feedforward of the current and the no-load voltage can be collectively suppressed, and the load can be operated stably by increasing the coefficient value of the multiplier. Further, there is an effect that the sum of the maximum values of the current feedback and the voltage feedforward is kept constant, and even when the load voltage becomes too high, the control can be performed safely.

According to the twenty-eighth aspect of the present invention, at least one of the switches is replaced with a limiter.
The inrush current at the time of reloading the load due to saturation of the proportional integrator when no current is flowing and the inrush current at the time of load reloading due to no-load voltage feedforward can be suppressed collectively and the limiter limit value By increasing the load, there is an effect that the load can be operated stably. Further, there is an effect that the sum of the maximum values of the current feedback and the voltage feedforward is kept constant, and even when the load voltage becomes too high, the control can be performed safely.

According to the invention of claim 29, since one of the switches is replaced by a limiter and one is replaced by a multiplier, the proportional integrator is saturated when no current flows. The inrush current at the time of load reloading and the inrush current at the time of load reloading due to feed-forward of no-load voltage can be suppressed at the same time, and stable by increasing the multiplier coefficient value and limiter limit value. This has the effect that the load can be operated. Further, there is an effect that the sum of the maximum values of the current feedback and the voltage feedforward is kept constant, and even when the load voltage becomes too high, the control can be performed safely.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a power supply control device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a power supply control device according to Embodiment 2 of the present invention.

FIG. 3 is a configuration diagram of a power supply control device according to Embodiment 3 of the present invention.

FIG. 4 is a configuration diagram of a power supply control device according to Embodiment 4 of the present invention.

FIG. 5 is a configuration diagram of a power supply control device according to Embodiment 5 of the present invention.

FIG. 6 is a configuration diagram of a power supply control device according to Embodiment 6 of the present invention.

FIG. 7 is a configuration diagram of a power supply control device according to Embodiment 7 of the present invention.

FIG. 8 is a configuration diagram of a power supply control device according to an eighth embodiment of the present invention.

FIG. 9 is a configuration diagram of a power supply control device according to Embodiment 9 of the present invention.

FIG. 10 is a configuration diagram of a power supply control device according to Embodiment 10 of the present invention.

FIG. 11 is a configuration diagram of a power supply control device according to Embodiment 11 of the present invention.

FIG. 12 is a configuration diagram of a power supply control device according to Embodiment 12 of the present invention.

FIG. 13 is a configuration diagram of a power supply control device according to Embodiment 13 of the present invention.

FIG. 14 is a configuration diagram of a power supply control device according to Embodiment 14 of the present invention.

FIG. 15 is a configuration diagram of a power supply control device according to Embodiment 15 of the present invention.

FIG. 16 is a configuration diagram of a power supply control device according to Embodiment 16 of the present invention.

FIG. 17 is a configuration diagram of a power supply control device according to a seventeenth embodiment of the present invention.

FIG. 18 is a configuration diagram of a power supply control device according to Embodiment 18 of the present invention.

FIG. 19 is a configuration diagram of a power supply control device according to Embodiment 19 of the present invention.

FIG. 20 is a configuration diagram of a power supply control device according to Embodiment 20 of the present invention.

FIG. 21 is a configuration diagram of a power supply control device according to Embodiment 21 of the present invention.

FIG. 22 is a configuration diagram of a power supply control device according to Embodiment 22 of the present invention.

FIG. 23 is a configuration diagram of a power supply control device according to Embodiment 23 of the present invention.

FIG. 24 is a configuration diagram of a power supply control device according to Embodiment 24 of the present invention.

FIG. 25 is a configuration diagram of a power supply control device according to Embodiment 25 of the present invention.

FIG. 26 is a configuration diagram of a power supply control device according to Embodiment 26 of the present invention.

FIG. 27 is a configuration diagram of a power supply control device according to Embodiment 27 of the present invention.

FIG. 28 is a configuration diagram of a power supply control device according to Embodiment 28 of the present invention.

FIG. 29 is a configuration diagram of a power supply control device according to Embodiment 29 of the present invention.

FIG. 30 is a configuration diagram of a power supply control device according to Embodiment 30 of the present invention.

FIG. 31 is a configuration diagram of a power supply control device according to Embodiment 31 of the present invention.

FIG. 32 is a configuration diagram of a power supply control device according to Embodiment 32 of the present invention.

FIG. 33 is a configuration diagram of a power supply control device according to Embodiment 33 of the present invention.

FIG. 34 is a configuration diagram of a power supply control device according to Embodiment 34 of the present invention.

FIG. 35 is a configuration diagram of a power supply control device according to Embodiment 35 of the present invention.

FIG. 36 is a configuration diagram of a power supply control device according to Embodiment 36 of the present invention.

FIG. 37 is a configuration diagram of a power supply control device according to Embodiment 37 of the present invention.

FIG. 38 is a configuration diagram of a power supply control device according to Embodiment 38 of the present invention.

FIG. 39 is a configuration diagram of a power supply control device according to Embodiment 39 of the present invention.

FIG. 40 is a configuration diagram of a power supply control device according to Embodiment 40 of the present invention.

FIG. 41 is a configuration diagram of a power supply control device according to Embodiment 41 of the present invention.

FIG. 42 is a configuration diagram of a power supply control device according to Embodiment 42 of the present invention.

FIG. 43 is a configuration diagram of a power supply control device according to Embodiment 43 of the present invention.

FIG. 44 is a configuration diagram of a power supply control device according to Embodiment 44 of the present invention.

FIG. 45 is a configuration diagram of a power supply control device according to Embodiment 45 of the present invention.

FIG. 46 is a configuration diagram of a power supply control device according to Embodiment 46 of the present invention.

FIG. 47 is a configuration diagram of a power supply control device according to Embodiment 47 of the present invention.

FIG. 48 is a configuration diagram of a power supply control device according to Embodiment 48 of the present invention.

FIG. 49 is a configuration diagram of a power supply control device according to Embodiment 49 of the present invention.

FIG. 50 is a configuration diagram of a power supply control device according to Embodiment 50 of the present invention.

FIG. 51 is a configuration diagram of a power supply control device according to Embodiment 51 of the present invention.

FIG. 52 is a configuration diagram of a power supply control device according to Embodiment 52 of the present invention.

FIG. 53 is a configuration diagram of a power supply control device according to Embodiment 53 of the present invention.

FIG. 54 is a configuration diagram of a power supply control device according to Embodiment 54 of the present invention.

FIG. 55 is a configuration diagram of a power supply control device according to Embodiment 55 of the present invention.

FIG. 56 is a configuration diagram of a power supply control device according to Embodiment 56 of the present invention.

FIG. 57 is a configuration diagram of a power supply control device according to Embodiment 57 of the present invention.

FIG. 58 is a configuration diagram of a power supply control device according to Embodiment 58 of the present invention.

FIG. 59 is a configuration diagram of a power supply control device according to Embodiment 59 of the present invention.

FIG. 60 is a configuration diagram of a power supply control device according to Embodiment 60 of the present invention.

FIG. 61 is a configuration diagram of a power supply control device according to Embodiment 1 of the present invention.

FIG. 62 is a configuration diagram of a power supply control device according to Embodiment 2 of the present invention.

FIG. 63 is a configuration diagram of a power supply control device according to Embodiment 3 of the present invention.

FIG. 64 is a configuration diagram of a proportional integrator 20 with a limiter according to a sixth embodiment of the present invention.

FIG. 65 is a configuration diagram of a conventional arc control device.

[Explanation of symbols]

1 transformer, 2 rectifier, 3 arc furnace body, 4 arc furnace electrode, 5 phase angle controller, 6 voltage converter, 7
Subtractor, 8 adder, 9 proportional integrator, 10 current detector, 11 voltage detector, 12 electrode lifting / lowering device, 13 electrode lifting / lowering control device, 14 current converter, 15, 18, 21
Switch, 16, 19, 22 Multiplier, 16a, 19
a, 22a coefficient value controller, 17, 23 variable limiter, 17a, 23a limit value controller, 24 DC reactor, 20 proportional integrator with limiter, 25, 26 resistor, 27 capacitor, 28 amplifier, 29 variable limiter.

Claims (29)

[Claims] 1. A proportional integral calculation of a deviation between a load current flowing through a switching element type rectifier that supplies DC power to a load and a preset load current, and a control signal based on the deviation is generated to generate the control signal. Current feedback control means including a proportional integrator for outputting to the load, a voltage related to the load is detected, and a voltage feedforward output according to the load voltage is added to the control signal so as to follow the load voltage by an adder. A power supply control device comprising: a voltage feedforward control unit configured to input the added output to the rectifier. A control signal limiting unit configured to limit a control signal output to the rectifier when the load is turned on again after the load is cut off. And a power supply control device for suppressing an inrush current flowing through the rectifier at the time of reloading the load. 2. The power supply control according to claim 1, wherein the control signal limiting means limits at least one of an output signal of the proportional integrator of the current feedback control means, a voltage feedforward output and an addition output. apparatus. 3. The control signal limiting means for limiting the voltage feedforward output comprises a first switch for switching the input to the adder from the voltage feedforward output to an initial value of a predetermined level when the load is turned on again. The power supply control device according to claim 2, wherein: 4. The control signal limiting means for limiting the voltage feedforward output multiplies the voltage feedforward output generated when the load is turned on again by a predetermined coefficient value, sets the initial value to a predetermined level, and inputs the initial value to the adder. 3. The power supply control device according to claim 2, wherein the power supply control device is configured by multiplying means for increasing the coefficient value to 1 after being turned on. 5. The control signal limiting means for limiting the voltage feedforward output limits the voltage feedforward performed at the time of reloading the load to a constant value and inputs the voltage feedforward to the adding section, and increases the limit value after the load is turned on. The power supply control device according to claim 2, wherein the power supply control device is configured by a going limiter. 6. The control signal limiting means for limiting the output signal of the proportional integrator comprises a second switch for switching the input to the adder to an initial value of a predetermined level from the output signal when the load is turned on again. The power supply control device according to claim 2, wherein: 7. A control signal limiting means for limiting an output signal of the proportional integrator, multiplies the output signal by a predetermined coefficient value at the time of reloading the load, sets the initial value to a predetermined level, and inputs the initial value to the adder. 3. The power supply control device according to claim 2, wherein the power supply control device is configured by multiplying means for increasing the coefficient value to 1. 8. A control signal limiting means comprising a built-in limiter for limiting an output signal in a proportional integrator, and when the load is turned on again, the output signal is limited to a constant value by the limiter and input to an adder. 3. The power supply control device according to claim 2, wherein the limit value of the limiter is increased after a load is applied. 9. The control signal limiting means for limiting the added output is constituted by a third switch for switching the input to the rectifier to switch the added output to an initial value of a predetermined level when reloading the load. The power supply control device according to claim 2. 10. A control signal limiting means for limiting the added output of the output signal of the proportional integrator and the voltage feedforward output, multiplies the added output input to the rectifier at the time of reloading the load by a predetermined coefficient value to obtain a predetermined value. 3. The power supply control device according to claim 2, wherein the power supply control device is constituted by multiplying means for setting a level to an initial value and increasing a coefficient value to 1 after a load is applied. 11. The control signal limiting means for limiting the added output is constituted by a limiter which limits the added output input to the rectifier to a constant value when the load is turned on again, and increases the limit value after the load is turned on. The power supply control device according to claim 2, wherein: 12. A control signal limiting means for limiting a voltage feedforward output and an output of a proportional integrator, wherein the input to the adder is switched from the voltage feedforward output to an initial value of a predetermined level when the load is turned on again. 3. The switch according to claim 2, wherein the first switch is configured to switch the input to the addition unit to an initial value of a predetermined level from the output of the proportional integrator when the load is turned on again. 4. Power control unit. 13. The power supply control device according to claim 12, wherein at least one of said switches is replaced by a multiplier. 14. The power supply control device according to claim 12, wherein at least one of the switches is replaced with a limiter. 15. The power supply control device according to claim 12, wherein one of said switches is replaced by a limiter, and the other is replaced by a multiplier. 16. A first switch for switching and inputting a control signal limiting means for limiting the voltage feedforward output and the addition output to an initial value of a predetermined level from the voltage feedforward output when the load is turned on again. 3. The power supply control device according to claim 2, comprising a third switch for switching and inputting the added output to an initial value of a predetermined level. 17. The power supply control device according to claim 16, wherein at least one of the switches is replaced with a multiplier. 18. The power supply control device according to claim 16, wherein at least one of the switches is replaced with a limiter. 19. The power supply control device according to claim 16, wherein one of said switches is replaced by a limiter and the other is replaced by a multiplier. 20. A first control signal limiter for limiting a voltage feedforward output, an addition output, and an output of a proportional integrator, which is switched from the voltage feedforward output to an initial value of a predetermined level when the load is turned on again. A switch, a third switch for switching and inputting the added output to an initial value of a predetermined level when the load is turned on again, and a second switch for switching and inputting the output of the proportional integrator to an initial value of the predetermined level when the load is turned on again. The power supply control device according to claim 2, wherein: 21. The power supply control device according to claim 20, wherein at least one of the switches is replaced with a multiplier. 22. The power supply control device according to claim 20, wherein at least one of the switches is replaced with a limiter. 23. The power supply control device according to claim 20, wherein two of said switches are replaced by multipliers and one of said switches is replaced by a limiter. 24. The power supply control device according to claim 20, wherein two of said switches are replaced by limiters and one is replaced by a multiplier. 25. The power supply control device according to claim 20, wherein one of said switches is replaced by a limiter and one is replaced by a multiplier. 26. A third switch, comprising: a third switch for switching and inputting the added output to an initial value of a predetermined level when the load is turned on again, each of control signal limiting means for limiting the addition output and the output of the proportional integrator; 3. The power supply control device according to claim 2, further comprising a second switch that switches the output of the proportional integrator to an initial value of a predetermined level when the power is turned on again. 27. The power supply control device according to claim 26, wherein at least one of the switches is replaced with a multiplier. 28. The power supply control device according to claim 26, wherein at least one of the switches is replaced with a limiter. 29. The power supply control device according to claim 20, wherein one of the switches is replaced by a limiter and one is replaced by a multiplier.