JPH10201236A - Power supply - Google Patents

Abstract

(57) [Problem] To provide a power supply device in which the operation at the start or end of a power factor improvement operation is stabilized and reliability is improved. SOLUTION: A power factor improvement control means 13 monitors a load level, and when the load level becomes larger than a first predetermined load level, generates a short-circuit pulse to drive a short-circuit element 10, thereby The power supply power factor is improved by short-circuiting the AC power supply 1 via the reactor 2 and the short-circuit element 10, and when the load level becomes lower than the second predetermined load level, the generation of the short-circuit pulse is terminated and the power supply is terminated. The power factor improvement operation ends.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device in which the power supply power factor is improved by short-circuiting the power supply through a reactor connected in series to the power supply, and more particularly to a power supply capable of operating at high speed and having excellent controllability. Related to the device.

[0002]

2. Description of the Related Art To extract more active power from a power supply, it is effective to improve the power factor of the power supply, and to increase the maximum capacity of the equipment by supplying a large amount of active power to the equipment of the load. be able to. In addition, by improving the power supply power factor, it is often possible to reduce the harmonic current of the power supply, which has recently become a problem, and it is possible to comply with domestic and foreign harmonic current regulations.

As a method for improving the power factor of a power supply device, there is a method disclosed in, for example, JP-A-7-7946. In this publication, a power supply is short-circuited through a reactor by a short-circuit element. Specifically, a short-circuit of a reactor is started according to a load state, a short-circuit current, a harmonic current content, a power supply power factor, a waveform distortion factor, and the like. Delay time and short circuit period.

[0004]

In a conventional method for improving the power factor of a power supply device, a short-circuit pulse is generated in a transient state when starting a power factor improving operation or ending the power factor improving operation. There is nothing described, but at the start or end of the power factor correction operation, the operation becomes unstable due to vibration, sudden rise and fall of the output voltage, and also adversely affects the operation of the load. There is.

[0005] The present invention has been made in view of the above,
An object of the present invention is to provide a power supply device in which the operation at the start or end of the power factor improvement operation is stabilized and the reliability is improved.

[0006]

According to the present invention, there is provided a rectifier for rectifying an AC voltage from an AC power supply into a DC voltage, and a reactor connected in series to the rectifier. A short-circuit means for short-circuiting the AC power supply via the reactor; and a short-circuit pulse generating means for generating a short-circuit pulse for driving the short-circuit means to a short-circuit state. Controlling the short-circuit pulse generating means to start generating the short-circuit pulse when the load level becomes higher than a first predetermined load level, and wherein the load level is lower than or equal to a second load level lower than the first predetermined load level. In this case, the gist of the present invention is to have a start / end control means for controlling the short-circuit pulse generation means so as to end the generation of the short-circuit pulse when the above condition is satisfied.

According to the present invention, when the load level becomes larger than the first predetermined load level,
The generation of the short-circuit pulse is started, and when the voltage falls below the second load level, the generation of the short-circuit pulse is terminated and the first load level is made larger than the second load level. When it is small, it is possible to avoid the adverse effect of performing the power factor improving operation and distorting the current waveform, and it is possible to prevent a sudden change in the DC output voltage and an unstable operation of the load.

According to a second aspect of the present invention, there is provided a rectifier for rectifying an AC voltage from an AC power supply into a DC voltage, a reactor connected in series to the rectifier, and a short circuit of the AC power supply via the reactor. And a short-circuit pulse generating means for generating a short-circuit pulse for driving the short-circuit means into a short-circuit state, wherein the width of the short-circuit pulse is gradually increased at the start of generation of the short-circuit pulse. Thus, the gist of the invention is to have a pulse width expansion control means for controlling the short-circuit pulse generation means.

According to the second aspect of the present invention, since the width of the short-circuit pulse is gradually increased at the start of the generation of the short-circuit pulse, a rapid rise of the DC output voltage and a sudden change of the power supply current and the DC output voltage are prevented. And a stable operation can be performed.

Further, according to the present invention, there is provided a rectifier for rectifying an AC voltage from an AC power supply to a DC voltage, a reactor connected in series to the rectifier, and short-circuiting the AC power supply via the reactor. And a short-circuit pulse generating means for generating a short-circuit pulse for driving the short-circuit means to a short-circuit state, wherein the width of the short-circuit pulse is gradually reduced when the generation of the short-circuit pulse is completed. The gist of the present invention is to have a pulse width reduction control means for controlling the short-circuit pulse generation means.

According to the third aspect of the present invention, since the width of the short-circuit pulse is gradually reduced at the end of the generation of the short-circuit pulse, a rapid rise in the DC output voltage and a sudden change in the power supply current and the DC output voltage are prevented. And a stable operation can be performed.

According to a fourth aspect of the present invention, when the load level of the AC power supply is smaller than a third predetermined load level, the generation of the short-circuit pulse is immediately terminated. The present invention is characterized in that there is provided an immediate end control means for controlling the short-circuit pulse generation means, and the third predetermined load level is a level lower than a load level at the time when the short-circuit pulse generation ends.

According to the present invention, when the load level is smaller than the third predetermined load level, the generation of the short-circuit pulse is immediately terminated, so that a sharp increase in the DC output voltage is prevented. Thus, the load can be protected from overvoltage.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a circuit configuration of a power supply device according to a first embodiment of the present invention. The power supply device shown in FIG. 1 has a reactor 2 having one end connected to one output end of an AC power supply 1, and the other end of the reactor 2 has a first diode bridge 3 and a full-wave rectifier. It is connected to one input terminal of each of the second diode bridges 9 that align the direction of the current. The other input terminals of the first and second diode bridges 3 and 9 are connected to the other output terminal of the AC power supply 1.

The output terminal of the first diode bridge 3 is connected to the load 7 via the smoothing electrolytic capacitors 4, 5, and 6, whereby the AC voltage from the AC power supply 1 is applied to the first diode bridge 3 and the smoothing capacitor. Electrolytic capacitors 4,5
The voltage is rectified by the doubler 6 and supplied to the load 7 as a DC voltage.

Both output terminals of the second diode bridge 9 are, for example, IGBT, bipolar transistor, MOS
Short-circuit element 10 which is a switching element composed of an FET or the like
Connected between the collector and the emitter of the
When 0 is turned on, the AC power supply 1 is short-circuited through the second diode bridge 9 and the reactor 2, thereby improving the power supply power factor of the power supply device. The gate of the short-circuit element 10 is connected to the power factor improvement control means 13, and the short-circuit element 10 is turned on by driving the short-circuit element 10 by the power factor improvement control means 13.

Further, zero-crossing detecting means 12 is connected to both output terminals of the AC power supply 1, and the zero-crossing detecting means 12 detects a point in time at which the AC voltage of the AC power supply 1 passes through the zero-crossing point, and converts this detection signal into a power factor. The information is supplied to the improvement control means 13. The control circuit 11 is composed of the zero-cross detection means 12 and the power factor improvement control means 13, and the control circuit 11 is composed of, for example, a microcomputer. Further, the load level of the power supply device is input to the power factor improvement control means 13.

FIG. 2 is a diagram showing a circuit configuration of a power supply device according to a second embodiment of the present invention. In the power supply device shown in FIG. 1, one end of a reactor 2 is connected to one output terminal of a first diode bridge 3 for full-wave rectification of an AC voltage of an AC power supply 1, and the other end of the reactor 2 is connected to a first diode. A collector and an emitter of a short-circuiting element 10 composed of a switching transistor are connected to the other output terminal of the bridge 3, and when the short-circuiting element 10 is turned on, the AC power supply 1 is connected via the reactor 2 and the first diode bridge 3. Are short-circuited. The other end of the reactor 2 is connected to a smoothing electrolytic capacitor 6 and a load 7 via a diode 15 for preventing backflow. When the short-circuiting element 10 is turned on to short-circuit the AC power supply 1 via the reactor 2 and the first diode bridge 3, the diode 15
It works so that the capacitor 6 is not short-circuited.

Further, similarly to the power supply device shown in FIG.
The power factor improvement control means 13 is connected to the gate of 0, and the zero cross detection means 12 and the power factor improvement control means 13 have the same function and configuration as those shown in FIG.

FIG. 3 is a functional block diagram for explaining the operation principle of the power supply shown in FIGS. 1 and 2 in an easy-to-understand manner, and particularly shows the internal configuration of the control circuit 11. As shown in FIG. 3, the control circuit 11 of the power supply device shown in FIGS. 1 and 2 includes a zero-cross detection unit 12 and a power factor improvement control unit 13. The power factor improvement control unit 13 determines a load level. A load level determination unit 31; a start / end processing unit 32 for controlling processing at the start and end of the power factor improvement operation; and a steady processing unit 33 for performing a steady power factor improvement process. Means 33
, A short-circuit pulse is supplied to the short-circuit element 10.

Next, the operation of the power supply units of the first and second embodiments shown in FIGS. 1 and 2 will be described with reference to FIG.
In FIG. 4, reference numeral 21 denotes a waveform of the AC voltage of the AC power supply 1, and reference numeral 22 denotes a
A waveform of a short-circuit pulse supplied to 0 is shown, and 23 represents a load level supplied to the power factor improvement control means 13 as an analog value.

When an AC voltage having a sinusoidal waveform as indicated by 21 in FIG. 4 is input from the AC power supply 1, the AC voltage is supplied to the first diode bridge 3 via the reactor 2 in FIG.
The voltage is supplied to a voltage doubler rectifier circuit composed of capacitors 4, 5, and 6, converted into a DC voltage, and supplied to a load 7.
In FIG. 2, the AC voltage from the AC power supply 1 is full-wave rectified by the first diode bridge 3 and then
And is smoothed by the capacitor 6 via the diode 15 and supplied to the load 7 as a DC voltage. Further, in this case, the zero-crossing detecting means 12 monitors the AC voltage from the AC power supply 1 and, when detecting the zero-crossing point, supplies this detection signal to the power factor improvement controlling means 13.

In the state where the DC voltage is supplied to the load 7, the load level indicated by reference numeral 23 in FIG.
Supplied to The load level determining means 31 compares the load level with a first predetermined load level A, and when the load level becomes larger than the first predetermined load level A, drives the start / end processing means 32 and starts / ends the processing. Under the control of the processing means 32, a short-circuit pulse as indicated by 22 in FIG. 4 is generated from the steady-state processing means 33 according to the zero-cross point detection signal from the zero-cross detection means 12, and the short-circuit pulse is generated by the short-circuit element 10.
To supply.

When the short-circuit pulse 22 is supplied to the short-circuit element 10, the short-circuit element 10 is turned on in response to the short-circuit pulse 22, whereby, in FIG. When the power supply 1 is short-circuited, and in FIG. 2 the AC power supply 1 is short-circuited via the reactor 2 and the first diode bridge 3, and when the short-circuit pulse disappears and the short-circuit element 10 is opened to the off state, the reactor 2 Is released to the load side. By short-circuiting the AC power supply 1 through the reactor 2 in this manner, the power supply current flows also in the phase section of the power supply where no current has flowed conventionally, and the conduction time of the current is extended, thereby reducing the power supply power factor. Can be improved.

The load level judging means 31 monitors the load level. When the load level becomes lower than the second predetermined load level B as shown in FIG. 4, the start / end processing means 32 is driven. Then, the generation of the short-circuit pulse from the steady-state processing unit 33 is stopped by the control of the start / end processing unit 32, thereby ending the power factor improvement processing.

As described above, in the present embodiment, the load level is monitored, and when the load level is small, the power factor improvement processing is not performed. Even if the operation is performed, the effect of improving the power factor is small, and conversely, the current waveform is prevented from being distorted and adversely affected.

In the above-described processing, by setting the first predetermined load level A to be larger than the second predetermined load level B (A> B), the start and end of the power factor improvement processing can be determined. Oscillation of the power factor improvement operation at the switching timing can be prevented. In this case, the hysteresis width is set so that the load can be operated stably based on the characteristics of the load, the boost characteristic of the power supply device, and the response time of the power supply device and the load. Depending on the configuration of the power supply,
In some cases, the second predetermined load level B is set to substantially 0, and in such a case, the effect can be sufficiently exerted.

The power supply device having the power factor improvement function of the present invention has a boosting function. When the power factor improvement process is performed, the DC output voltage of the power supply device is smaller than that immediately before the power factor improvement is performed. Rise, and the effective value of the power supply current decreases. Therefore, when the load is an electric motor or the like, if there is no hysteresis, the speed of the electric motor oscillates, causing an unstable operation, and in some cases, stopping. However,
In the power supply device of the present invention, the power factor improvement operation does not frequently switch at a load level near the start and end of the power factor improvement process, so that the DC output voltage oscillates or the power supply current of the power supply device is reduced. The DC output voltage does not oscillate, and even if the power factor is improved, the DC output voltage gradually increases, and a stable operation can be continuously performed.

In each of the above embodiments, the load level includes, specifically, power supply current, load current, output current, power factor, harmonic current, distortion factor, load control parameters,
For example, rotation speed, speed, temperature, humidity,
Various parameters that can determine the magnitude of the load, such as pressure and weight, can be used.

Next, a power supply device according to a third embodiment of the present invention will be described with reference to FIGS.

FIG. 5 is a functional configuration diagram of a main part for explaining the operation principle of the power supply device of the third embodiment in an easy-to-understand manner. The specific circuit configuration is shown in FIG. The power supply device having the above configuration can be similarly implemented. Since the circuit configuration of the power supply device shown in FIGS. 1 and 2 has already been described in detail, the operation of the third embodiment will be described with reference to FIG.

As shown in FIG. 5, the power supply device of the third embodiment differs from the first and second embodiments shown in FIG. And the operation is the same as that of FIG.

That is, the power factor improvement control means 1 shown in FIG.
3 is a load level determining means 31 for determining a load level.
Start processing means 34 for controlling processing at the start of the power factor improvement operation; and steady processing means 33 for performing steady power factor improvement processing.
And the start / end processing means 32 in FIG.
Instead, a start processing means 34 is provided.

When the supply of the short-circuit pulse to the short-circuit element 10 is started, the start processing means 34 controls the short-circuit pulse 24 such that the pulse width gradually increases from a small pulse width to a large pulse width as indicated by 24 in FIG. Is to occur.
In FIG. 6, reference numeral 21 denotes a waveform of the AC voltage of the AC power supply 1, 24 denotes a waveform of a short-circuit pulse whose pulse width changes gradually, and 25 denotes a load level as an analog value.

FIG. 7 shows the DC output voltage of the present power supply unit which changes in response to the short-circuit pulse 24 whose pulse width gradually increases as described above by using a solid line at reference numeral 42, and performs only the conventional steady processing. The change of the DC output voltage in the case of the above is indicated by reference numeral 41 by a dotted line. As shown in FIG. 7, by gradually increasing the width of the short-circuit pulse as in the present embodiment, the DC output voltage gradually increases, whereas the pulse width gradually decreases as in the related art. When the short-circuit pulse having the normal pulse width is suddenly supplied from the steady processing without increasing the DC output voltage, the DC output voltage sharply increases.

More specifically, in the third embodiment shown in FIG. 5, the load level judging means 31 monitors the load level of the power supply, and when the load level becomes larger than the predetermined power factor improvement level, When it is detected that the power factor improvement processing has started, the start processing means 34 is driven to execute the processing shown in FIG.
As shown by 24, a short-circuit pulse whose pulse width changes gradually greatly is generated, and the short-circuit element 10 is driven by this short-circuit pulse, thereby short-circuiting the AC power supply 1 via the reactor 2 and performing power factor improvement processing. Start.

When the pulse width of the short-circuit pulse gradually increases and becomes equal to the pulse width originally output by the steady processing means 33, the load level determining means 31 replaces the start processing means 34 with the steady state. The processing unit 33 is driven to generate a short-circuit pulse having a predetermined pulse width in a steady state from the steady-state processing unit 33, and the short-circuit element 10 is driven by the short-circuit pulse in the steady state to perform a steady-state power factor improvement process. . In FIG. 6, the number of short-circuit pulses is reduced for simplification.

The speed at which the pulse width of the short-circuit pulse is gradually increased is set to a value that allows stable operation based on load characteristics, boost characteristics of the power supply device, and response times of the power supply device and the load. You. Specifically, the short-circuit pulse is
For example, the pulse width is increased for each pulse at a speed of about 1 μS / 10 ms to 50 μS / 10 ms or lower. In addition, 10 mS means that the frequency of the AC power supply 1 is 50
In the case of Hz, it is の of the cycle of the AC power supply 1.

The power supply device having the power factor improvement function of the present invention has a boosting function. When the power factor improvement process is performed, the DC output voltage of the power supply device is smaller than that immediately before the power factor improvement is performed. Rise, and the effective value of the power supply current decreases. If a short-circuit pulse for improving the power factor is immediately output with a predetermined pulse width as in the related art, the DC output voltage sharply increases and the load current sharply decreases. For this reason, when the load is an electric motor or the like, the speed suddenly increases and the operation becomes unstable, and in some cases, the operation stops. However, in the power supply device of the present invention, since the width of the short-circuit pulse for improving the power factor gradually increases, the DC output voltage does not suddenly increase, and the power supply current and the DC output voltage do not change suddenly. Even when the improvement operation is started, a stable operation can be continuously performed.

In this embodiment, the load level is monitored by the load level judging means 31, and when the load level exceeds a predetermined level, a short-circuit pulse is generated to perform a power factor improvement operation. When the load level is small, the power factor improvement process is not performed.However, even if the power factor improvement operation is performed when the load level is small, the power factor improvement effect is small, and conversely, the current waveform is This prevents distortion and adverse effects in some cases. However, a short-circuit pulse is generated from a state in which the load level is almost 0 (in this case, the short-circuit pulse may have a pulse width short enough to have no effect on power factor improvement), or the short-circuit pulse is generated at the same time when the power supply device is started. It is obvious that the present embodiment can also exert the same effect when outputting.

Next, a power supply device according to a fourth embodiment of the present invention will be described with reference to FIGS.

FIG. 8 is a functional configuration diagram of a main part for easily explaining the operation principle of the power supply device of the fourth embodiment. The specific circuit configuration is shown in FIG. The power supply device having the above configuration can be similarly implemented. Since the circuit configuration of the power supply device shown in FIGS. 1 and 2 has already been described in detail, the operation of the fourth embodiment will be described with reference to FIG.

As shown in FIG. 8, the power supply device according to the fourth embodiment differs from the power supply device according to the third embodiment shown in FIG. It is the same as that of FIG.

That is, the power factor improvement control means 1 shown in FIG.
3 is a load level determining means 31 for determining a load level.
And end processing means 35 for controlling processing at the end of the power factor improvement operation, and steady processing means 33 for performing steady power factor improvement processing.
And an end processing means 35 is provided in place of the start processing means 34 in FIG.

At the end of the generation of the short-circuit pulse supplied to the short-circuit element 10, that is, at the end of the power factor improvement processing, the end processing means 35 outputs a pulse having a large pulse width in the steady processing as indicated by 26 in FIG. This is to generate a short-circuit pulse 26 which gradually reduces from a width to a small pulse width.
In FIG. 9, reference numeral 21 denotes a waveform of the AC voltage of the AC power supply 1, 26 denotes a waveform of a short-circuit pulse whose pulse width gradually changes, and 27 denotes a load level as an analog value.

FIG. 10 shows the DC output voltage of the present power supply which changes in response to the short-circuit pulse 26 whose pulse width gradually changes as described above by a solid line at reference numeral 44, and shows only the conventional steady processing. The change of the DC output voltage in the case where the operation is performed is indicated by a dotted line with reference numeral 43. As shown in FIG. 10, by gradually reducing the width of the short-circuit pulse as in the present embodiment, the DC output voltage gradually decreases, whereas the pulse width gradually decreases as in the related art. When the supply of the short-circuit pulse is suddenly stopped from the steady processing without reducing the DC output voltage, the DC output voltage suddenly decreases.

More specifically, in the fourth embodiment shown in FIG. 8, the load level judging means 31 monitors the load level 27 of the power supply and detects that the load level has become lower than a predetermined level. Then, the termination processing means 35
To generate a short-circuit pulse whose pulse width gradually changes as shown at 26 in FIG. 9, and drives the short-circuit element 10 with the decreasing short-circuit pulse. Power supply 1 is short-circuited. Then, when the pulse width of the short-circuit pulse becomes substantially zero, the generation of the short-circuit pulse ends, and the power factor improvement processing ends. In FIG. 8, the number of short-circuit pulses is reduced for simplification.

The speed at which the pulse width of the short-circuit pulse is gradually reduced depends on the characteristics of the load, the boosting characteristics of the power supply device,
The value is set to a value that allows stable operation based on the response time of the power supply device and load. Specifically, the short-circuit pulse is, for example, 1 μS / 10 ms to 50 μS / 10 ms.
The pulse width is reduced for each pulse at a speed before or after or at a speed lower than that.

The power supply device having the power factor improving function of the present invention has the boosting function. When the power factor improving process is stopped, the DC output voltage is reduced as compared with the state immediately before performing the power factor improving process. , The power supply current increases. For this reason, when the load is an electric motor or the like, the speed is suddenly reduced and the operation becomes unstable, and in some cases, the operation is stopped. However, in the power supply device of the present invention, since the width of the short-circuit pulse for improving the power factor gradually decreases, the DC output voltage does not sharply increase, and the power supply current and the DC output voltage do not suddenly change. Even after the improvement operation is completed, the DC output voltage gradually decreases, and a stable operation can be continuously performed.

In this embodiment, the load level is monitored by the load level judging means 31. If the load level is low, the short-circuit pulse is not output, so that the power factor improvement processing is not performed. This prevents the power factor improving effect from being small even if the power level improving operation is performed when the load level is small, and rather prevents the current waveform from being distorted and adversely affecting the operation. is there. However, it is clear that the same effect can be exerted even when the processing as in the present embodiment is performed when the load level becomes substantially zero.

Next, a power supply device according to a fifth embodiment of the present invention will be described with reference to FIGS.

FIG. 11 is a functional configuration diagram of a main part for easily explaining the operation principle of the power supply device according to the fifth embodiment. The specific circuit configuration is shown in FIG. The power supply device having the above configuration can be similarly implemented. Since the circuit configuration of the power supply device shown in FIGS. 1 and 2 has already been described in detail, the fifth embodiment will be described with reference to FIG.
The operation of the embodiment will be described.

As shown in FIG. 11, the power supply device according to the fifth embodiment is different from the power supply device according to the fourth embodiment shown in FIG. Otherwise, the other configuration and operation are the same as those in FIG.

That is, in FIG. 11, the newly added emergency stop processing means 36 sets the load level at the end of the power factor improvement processing in which the pulse width of the short-circuit pulse is gradually reduced by the end processing means 35. When the level suddenly drops and becomes lower than a predetermined level, the generation of the short-circuit pulse is stopped, and the power factor improving process is stopped suddenly.

FIG. 12 shows this state. In FIG. 12, reference numeral 21 denotes a waveform of an AC voltage of the AC power supply 1;
Reference numeral 28 denotes a waveform of a short-circuit pulse in which the pulse width gradually decreases at the end of the power factor improvement. 29 denotes a load level as an analog value. Is also reduced to a small level.

More specifically, the fifth embodiment shown in FIG.
In the embodiment, the load level determination means 31 monitors the load level 29 (FIG. 12) of the power supply device, and when it is detected that the load level has become lower than the predetermined level, the end processing means 35 is driven. , A short-circuit pulse whose pulse width gradually changes as shown by 28 in FIG.
The short-circuit element 10 is driven by the short-circuit pulse that decreases, thereby short-circuiting the AC power supply 1 via the reactor 2.

In the course of this operation, when the load level suddenly drops as shown at 29 in FIG. 12 and falls below a level lower than a predetermined load level C, the load level judging means 31 turns to this load level. 29, the emergency stop processing means 36 is driven. As a result, the emergency stop processing means 36
The termination processing means 35 is controlled so as to stop the generation of the short-circuit pulse by the control unit 5, thereby ending the power factor improving operation.

The predetermined load level C is set to a value that can protect the load from the voltage allowable range of the load, the boost characteristic of the power supply circuit, the response time of the power supply circuit and the load, and the like. As a result of such processing, it is possible to prevent an abnormal increase in the DC voltage, protect the load from overvoltage, and realize a more reliable power supply device.

In each of the above embodiments, a power supply device having the same power factor improving function and the same effect even when the connection positions of the components such as the reactor, the short circuit, the capacitor, and the rectifier circuit are interchanged. The present invention can be similarly applied to various power supplies that have been replaced and changed as described above.

Further, in each of the above-described embodiments, the case where the number of short-circuit pulses is one has been described. However, even when two or more short-circuit pulses are used, the same effect as the present invention can be achieved. You can do it. For example, when the number of short-circuit pulses is two, the method of simultaneously increasing or decreasing the width of two short-circuit pulses, or the method of increasing or decreasing the width of one short-circuit pulse of two short-circuit pulses Then, the width of the other short-circuit pulse may be increased or decreased.

[0062]

As described above, according to the present invention, when the load level becomes higher than the first predetermined load level, the generation of the short-circuit pulse is started, and the generation of the second short-circuit pulse is started.
When the load level becomes equal to or less than the load level, the generation of the short-circuit pulse is terminated, and the first load level is set higher than the second load level. The adverse effect of distorting the current waveform can be avoided, and a sudden change in the DC output voltage and an unstable operation of the load can be prevented.

According to the second aspect of the present invention, since the width of the short-circuit pulse is gradually increased at the start of the generation of the short-circuit pulse, a sudden increase in the DC output voltage and a sudden change in the power supply current and the DC output voltage are prevented. Prevention and stable operation can be performed.

Further, according to the present invention, when the generation of the short-circuit pulse is completed, the width of the short-circuit pulse is gradually reduced, so that the DC output voltage sharply increases and the power supply current and the DC output voltage suddenly change. Prevention and stable operation can be performed.

According to the present invention, if the load level is smaller than the third predetermined load level at the end of the generation of the short-circuit pulse, the generation of the short-circuit pulse is immediately terminated. The voltage can be prevented from rising, and the load can be protected from overvoltage.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a circuit configuration of a power supply device according to a second embodiment of the present invention.

FIG. 3 is a functional configuration diagram for easily explaining the operation principle of the power supply device shown in FIGS. 1 and 2;

FIG. 4 is an operation waveform diagram for explaining an operation of the power supply devices of the first and second embodiments shown in FIGS.

FIG. 5 is a functional configuration diagram of a main part for clearly explaining the operation principle of the power supply device according to the third embodiment of the present invention.

6 is an operation waveform diagram for explaining an operation of the power supply device shown in FIG.

7 is an operation waveform diagram for explaining an operation of the power supply device shown in FIG.

FIG. 8 is a functional configuration diagram of a main part for easily explaining the operation principle of a power supply device according to a fourth embodiment of the present invention.

FIG. 9 is an operation waveform diagram for explaining an operation of the power supply device shown in FIG. 8;

FIG. 10 is an operation waveform diagram for explaining an operation of the power supply device shown in FIG. 8;

FIG. 11 is a functional configuration diagram of a main part for easily explaining the operation principle of a power supply device according to a fifth embodiment of the present invention.

12 is an operation waveform diagram for explaining an operation of the power supply device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply 2 Reactor 3 1st diode bridge 4,5,6 Capacitor 7 Load 9 2nd diode bridge 10 Short circuit element 11 Control circuit 12 Zero cross detection means 13 Power factor improvement control means 31 Load level judgment means 32 Start / end Processing means 33 Regular processing means 34 Start processing means 35 End processing means 36 Emergency stop processing means

Claims (4)

[Claims] 1. A rectifier for rectifying an AC voltage from an AC power supply to a DC voltage, a reactor connected in series to the rectifier, a short circuit for short-circuiting the AC power supply via the reactor, and a short circuit. A power supply device having a short-circuit pulse generation means for generating a short-circuit pulse for driving to a short-circuit state, wherein when the load level of the power supply device becomes higher than a first predetermined load level, generation of the short-circuit pulse is started. The short-circuit pulse generating means is controlled to cause the short-circuit pulse generating means to terminate the generation of the short-circuit pulse when the load level falls below a second load level lower than the first predetermined load level. Characterized by having start / end control means for controlling the power supply. 2. A rectifier for rectifying an AC voltage from an AC power supply into a DC voltage, a reactor connected in series to the rectifier, a short-circuit means for short-circuiting the AC power supply via the reactor, and a short-circuit means. A power supply device having a short-circuit pulse generating means for generating a short-circuit pulse for driving into a short-circuit state, wherein the short-circuit pulse generating means is controlled so as to gradually increase the width of the short-circuit pulse at the start of generation of the short-circuit pulse. A power supply device, comprising: 3. A rectifier for rectifying an AC voltage from an AC power supply to a DC voltage, a reactor connected in series to the rectifier, a short-circuit means for short-circuiting the AC power supply via the reactor, and a short-circuit means. A power supply device having short-circuit pulse generation means for generating a short-circuit pulse for driving to a short-circuit state, wherein the short-circuit pulse generation means is controlled to gradually reduce the width of the short-circuit pulse when the generation of the short-circuit pulse is completed. And a pulse width reduction control unit. 4. An immediate termination control unit that controls the short-circuit pulse generation unit to immediately terminate the generation of the short-circuit pulse when the load level of the AC power supply is lower than a third predetermined load level. 4. The power supply device according to claim 3, wherein the third predetermined load level is lower than a load level at the time when the generation of the short-circuit pulse is completed.