JPS60200321A - Electric power converter - Google Patents

Abstract

PURPOSE:To reduce the surge voltage which is produced when a current is cut off by using an arithmetic means to calculate the 2nd reference voltage, and arc- extinguishing a switching element when the cumulative value of converter outputs reaches the 2nd reference voltage. CONSTITUTION:An operator 12 consists of a broken line approximating circuit like a converter 6 and supplies the 1st reference voltage Vref1 to produce the 2nd reference voltage Vref2. This voltage Vref2 is supplied to a reverse input terminal of a comparator 8. An integrator 7 integrates the load power after an ignition phase every half cycle of an AC power supply, and this integration output is supplied to a non-reverse input terminal of the comparator 8. The comparator 8 compares the integration output fed from the integrator 7 with the voltage Vref2. When the former exceeds the latter, the comparison output is produced to reset an FF3. Therefore transistors Tr131 and 132 of a drive circuit 13 are turned on and off respectively. Thus a drive transformer 133 is de- energized. Then a main Tr41 of a switching circuit 4 is arc-extinguished since the supply of base current is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a power converter that supplies a load with an output whose phase is controlled every half cycle of an AC power supply, and in particular, to a power converter that supplies a load with an output whose phase is controlled every half cycle of an AC power supply, and in particular, to The present invention relates to a power conversion device using a so-called front conduction/completion phase control method.

(Background of the Invention) Conventionally, in this type of device, as shown in FIG.
The ignition phase φ1 was fixed and the extinguishing phase φ2 was made variable to control dimming, output stabilization, etc.

Next, the operation of the conventional power converter shown in the block diagram of FIG. 2 will be explained with reference to the time chart of FIG. 3. Each waveform in FIG. 3 corresponds to the part indicated by the numerical value circled in FIG. 2.

The rectifier 1 generates a full-wave rectified output (pulsating output) ■ from the AC power supply voltage ■, and the zero-crossing detector 2 slices this pulsating output ■ at a predetermined threshold, and detects that only the vicinity of the zero crossing is at a low level and the others. generates a high level zero detection output (■). This ze[1 and ds detection output (■) is generated. This zero cross detection output ■ is solipf L1tsu7 (F / [
2>3, and F/[-3 is let at the rising edge of this zero-cross detection output horn. This results in
The output ■ of the F/F 3 goes to a low level, and the transistors 1 to 41 that make up the switching circuit 4 turn on (fire).
(2) Reference input 1, that is, the ignition phase in the device shown in FIG. 2 is fixed to the rising phase of the output pulse waveform (2) of the zero cross detector 2.

On the other hand, this power converter rectifies the output voltage, that is, the voltage supplied to a load (not shown) with a rectifier 5), converts the voltage to power with a converter 6 (■), and integrates it with an integrator 7 (■).
). Here, the converter 6 converts the voltage (instantaneous value) into the power (
There is a variable in the instantaneous value). In this case, the applied voltage versus power consumption curve is expressed, for example, by the general formula w=vn,
If the load is a pure resistance, n is 2, and if the load is a discharge lamp, n is a value between 0 and 5 to 1.5 depending on the type of discharge lamp or ballast. The converter 6 is used by changing its characteristics to match such a curve depending on the load.

The integrator 7 receives the low level signal of the previous 1 ffl zero cross detection output (2) as a reset signal, and thereby integrates the load consumption voltage for each half cycle of the AC power supply voltage (2) and outputs -C. This integrated power 111 is supplied to one input of the comparator 8.

The comparator 8 compares the reference voltage V rero supplied from the reference voltage generation circuit 9 to the other input terminal with the integrated output (2), and this integrated output (2) is the reference voltage V ref.

Comparison output ■ is generated when the value is exceeded. This comparison output (2) is supplied to the reset terminal of the F/F3, and when the F/F3 is turned on and the output (2) becomes low level, the transistor 41 is turned off. As a result, the transistor 41, that is, the switching circuit 4 is conductive from immediately after the zero cross until the load power reaches a predetermined power determined by the reference voltage Vre[0. Therefore, in the device shown in FIG. 2, even if the power supply varies, a constant amount of power can always be supplied to the load every cycle every year.

However, when performing phase control using the J: una after-clause method, as shown in FIG. 4, current interruption R? At time 1, a high voltage is generated, which has an adverse effect on other equipment connected to the common wiring or AC power supply, and in the worst case, may destroy these equipment. The cause of this surge voltage is the fifth
The energy stored in the inductance component LS (1/2 ・l
-3P) is suddenly released as a surge voltage when the current is interrupted.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems with the conventional type. In the power converter of the completion phase control method, as shown in Fig. 6, the output setting is changed by changing the firing phase φ1, and the extinguishing phase φ2 in the steady state is changed to the firing phase. Regardless of changes in φ1, the load voltage and current in the second half of the half cycle are set to be approximately constant at a relatively low phase, and the extinguishing phase φ2 is set to a negative value in response to fluctuations in the actual output value. Based on the concept of feedback control and constant C output, it is possible to control the surge voltage generated by cutting off the current when the arc is extinguished, and to stabilize it every cycle every year and supply lζ output to the load. The purpose of the present invention is to provide a power conversion device that can perform multiple functions.

(Structure of the Invention) In order to achieve the above object, the present invention uses an AC power source, and supplies a phase-controlled output to the load by turning on, turning off, and extinguishing the AC power every year. In a power conversion device comprising a switching element, and a control circuit that includes means for accumulating the output chambers for each annual cycle and controls the extinction phase of the switching element according to the accumulated value, the control circuit comprises: , means for generating a variable first reference voltage, and means for igniting the switching element in a phase corresponding to the first reference voltage, when the AC power source is kept constant with respect to the first reference voltage. 7. Calculates and overturns a second base Q'I 7ti pressure corresponding to the cumulative C1 value that is at a predetermined phase of 7. - the switching element is arc-extinguished.

(Effect of the Invention) If the present invention configured as described above is used, as shown in FIG. By making it possible to reduce the 4-noge voltage that occurs when current is cut off,
Since this →J voltage is superimposed on a relatively low portion of the AC power supply voltage, the peak value of the voltage that appears on the common wiring is reduced, and the present invention is applied to the common wiring or AC power supply. It is possible to prevent an adverse effect on the equipment connected in parallel with the power converter.

(Explanation of Examples) Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 8 shows the configuration of a power conversion device according to an embodiment of the present invention. Further, FIG. 9 shows a time chart of the operation of each part in the apparatus shown in FIG. Note that parts common or corresponding to those of the conventional example shown in FIGS. 2 and 3 are denoted by the same reference numerals.

The device shown in Fig. 8 differs from the one shown in Fig. 2 in that the zero-cross detector 2 and the 7-lip 70-tube (F/F) 3 are reset by a zero-cross detection knob between the two terminals. When the output 0 of this triangular wave generator 10 exceeds the first reference voltage Vre "1", the voltage of which is varied by the triangular wave generator 10 and an external variable resistor (not shown) for setting the output horn, etc. A comparator 11 that generates a second comparison output ■ and sends it to the set terminal of the F/F 3 is added, and a reference voltage is also connected between the reference voltage generation circuit 9 and the other input terminal of the comparator 8 The first reference voltage Vre[ output from the voltage generation circuit 0
1, a magnifier 12 is added which calculates a second reference voltage V ref2, which will be described later, and inverts the output.

FIG. 10 does not show a specific circuit example of the device shown in FIG. 8.

Note that in FIG. 10, a drive circuit 13 is connected between the flip-flop 3 and the switching circuit 4.

In Figure 10, C, zero cross detector 2 is full wave rectifier 1
The pulsating output (■) from the AC power supply voltage (2) is compared with a predetermined threshold voltage Vth, and only the AC power supply voltage (2) near the Nogero Cross generates a high-level U1 rich [1st detection output (2). The triangular wave generator 10 (includes an integrating circuit 101 that integrates a predetermined DC voltage VC, and a zero-cross detection output (■) that turns on and resets this integrating circuit 101 (H = E T' 102 etc. rtM), AC power source The comparator 11 generates a triangular wave voltage [phase] with one half of 1]° cycle as one cycle. When the triangular wave voltage (2) exceeds the first reference voltage Vref1, a high-level comparison signal 0 is generated.This comparison signal 0 is supplied to the cellar 1 to the cellar a of the F/F3. As a result, F/F3 is hit, and the inverted output Φ becomes a low level (inverted signal of ■).
is turned off, the 1-transistor 132 is turned on, the primary winding 133p of the drive transformer 133 is driven, and the main transistor 41 of the switching circuit 4 is connected to the drive 1-transistor 133.
A secondary winding 133S is supplied.

That is, by changing the first reference voltage Vre[1, the ignition phase angle φ1 can be freely changed.

Note that the diode 134 of the drive 1ijl path 13 is connected to the drive 1
~It is for resetting the lance 133. In addition, diodes 42, 43, 44, 45 forming a diode bridge in the switching circuit 4 are connected to the main transistor 41.
The series circuit of the resistor 4G and the converter 47 is a snubber circuit for protecting the main transistor 41.

On the other hand, the full-wave rectifier 5 performs this power conversion! ! A full-wave rectified output ■ is generated from the output voltage ■ at the i position. The converter 6 performs polygonal line approximation according to the load, and generates a voltage (2) corresponding to the load power (instantaneous value) from the rectified output voltage (2). The integrator 7 includes 46 integrator circuits 71 that integrate the load power signal (2) and FETs 72 that reset the integrator circuits 71. When this is at a low level, the high level No. 18 applied to the gate via the inverter 14 causes "t:
When 1-72 is turned on, it is reset, and when the comparison signal (2) becomes high level, the integration of the signal (2) starts. Therefore, the integrator 7 a3 integrates the load power horn after the ignition phase every 1 d and a half cycles of the AC power supply. This integral output ■ is supplied to the non-inverting input terminal of the comparator 8.

/'J N computing unit 12 is composed of a polygonal line approximation circuit similar to the converter 6, and inputs the first reference voltage V r (ifl) and calculates the second base 1%14 voltage v of the relationship shown by the curve in FIG. 11.
ref2 is generated and supplied to the inverting input of comparator 8.

The curve in FIG. 11 shows, for example, the phase φ2 when the reset input of F/F 3 in the circuit in FIG.
The output of the integrator 7 is converted to the voltage VrOf2 of the second base 11.
It can be determined by measuring as .

The comparator 8 compares the integral output ■ output from the integrator 7 with the second reference voltage Vref2 output from the arithmetic unit 12, and when the integral output ■ exceeds the second reference voltage Vref2. Generates comparison output ■ and supplies it to the resetting terminal of F/F3. As a result, F/F 3 is reset and the inverted output Q becomes high level.

Therefore, the transistor 131 of the drive circuit 13 is turned on, the transistor 132 is turned on, and the drive transformer 133 is deenergized. Then, the supply of base current to the main transistor 41 of the switching circuit 4 is stopped, and the main transistor 41 is turned off (extinguished). Here, the voltage generator 12 uses the first voltage as the second reference voltage.
Since a voltage is outputted according to the curve shown in FIG. 1, the arc-extinguishing phase at the rated input voltage is φ2, so the arc-extinguishing phase at the rated input voltage is, of course, φ2.

But power fluctuation or negative? If the output power ■ increases due to fluctuations in jJ, etc., and Jζ increases, the output of the integrator 7 will reach the second reference voltage V ref2 sooner, so the extinction phase will be φ
2, which keeps the output constant. Also,
When the output power decreases and becomes J, the extinction phase becomes φ2.
lag, which keeps the output constant. That is, even if the power supply voltage fluctuates or contains harmonics, the lightning voltage supplied to the load remains constant every half cycle.

Therefore, for example, when using a lighting load (especially an electronic safety f'' device), it is possible to prevent fluctuations due to power supply voltage fluctuations and harmonics. etc.) can be fixed at a predetermined value of 11, which is unrelated to the ignition phase, so if the extinguishing phase is set to a phase in which the load current and voltage values are low in the second half of the cycle, the surge voltage can be reduced. It can also be used to remove 771 negative effects on other organs.

In the case of d3, C stabilizes the power supplied to 0, but it also stabilizes the effective or average value of the output voltage or current, or in the case of a lighting load, the physical quantity such as illuminance. The arc phase may also be controlled.

[Brief explanation of the drawing]

Fig. 1 is a waveform diagram for explaining the conventional pre-conduction/completion phase control method, Fig. 2 is a block diagram of a conventional power conversion device, and Fig. 3 is a waveform diagram for explaining the conventional pre-conduction/completion phase control method. Figure 4 is the power supply voltage and output current waveform diagram of the device in Figure 2, Figure 5 is the equivalent circuit of the power distribution system, Figure 6 is A\
A waveform diagram showing the operating principle of the optical invention, FIG. 7 is a power supply voltage and output current waveform diagram when the present invention is applied, and FIG. 8 is a power supply voltage and output current waveform diagram according to an embodiment of the present invention. ! ! ! FIG. 9 is a block diagram of the device, and FIG. 9 is a diagram showing the signal timing of each part J3 LJ to the device of FIG. 8. FIG. 10 is a diagram showing a specific circuit example of the device of FIG. 10 is a graph showing the input/output characteristics of the arithmetic unit in FIGS. 8 and 10. FIG. 3... Noripno II tube, 4... Switching circuit, 7... Integrator, 8.11... Comparator, 9... Reference voltage generation circuit, 1
0... Triangular wave generator, 12... Arithmetic unit, 13...
drive circuit. Figure 3 Figure 4 Cause Figure 6 Figure 71 Figure 11 Vrefl [f] [Phase] ■ [Phase] @

Claims (1)

[Claims] 1. An AC power supply, a switching element that turns on and off every phase and half cycle of the AC power supply to supply a phase-controlled output to the load, and means for accumulating the output amount for each phase and half cycle. In the power converter device, the control circuit includes a control circuit that controls the extinction phase of the switching element according to the accumulated value, and the control circuit includes a means for generating a variable first reference voltage, and a first reference voltage. Means for igniting the switching element at a phase corresponding to the reference voltage 11, etc., means for firing the switching element at a phase corresponding to the reference voltage 11, etc. arithmetic means for calculating a reference voltage;
A power conversion device characterized in that the switching element is turned off when a reference voltage of 1 is reached.