JPS60200320A - Electric power converter - Google Patents

Abstract

PURPOSE:To control the surge voltage which is produced by the cut off of current at arc-extinguishing time and to eliminate the evil effects, by arc-extinguishing a switching element when the cumulative value of the converter outputs reaches the 2nd reference voltage. CONSTITUTION:A converter 6 performs the broken line approximation corresponding to a load against the input voltage and produces the voltage corresponding to the load power. An integrator 7 integrates the produced voltage, and a comparator 8 compares the integration output fed from the integrator 7 with the 2nd reference voltage Vref2 set at a preset volume. Then a comparison output is produced when the integration output exceeds the voltage Vref2 and supplied to a reset terminal of an FF3. Then the FF3 is reset and the reverse output is set at a high level. As a result, a transistor 152 of a drive circuit 15 is turned off and a drive transformer 153 is de-energized. Then a main transistor 41 of a switching circuit 4 is arc-extinguished since the supply of base current is cut off.

Description

[Detailed Description of the Invention] (Field of the Invention) Mizumoto... relates to a power conversion device that supplies a load with an output whose phase is controlled every half cycle of an AC power supply, and in particular, it relates to a power conversion device that supplies a load with an output whose phase is controlled every half cycle of an AC power supply, and in particular, with respect to both the ignition phase and the extinguishing phase. The present invention relates to a power conversion device of a so-called forward interrogation/interrupting phase control system.

(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 portion indicated by the circled numerical value in FIG. 2.

The rectifier 1 generates a full wave path outflow J (pulsating output) ■ from the AC power supply voltage ■, and the zero cross detector 2 slices this pulsating output ■ at a predetermined threshold value and detects that only those near the zero cross f'' are low. The other outputs generate a high-level zero-cross detection output ■. This 10 cross detection output (2) is supplied to a flip 70 tube (F/F) 3, and F/F 3 is set at the rising edge of this 1 (cross detection output (2)). As a result, the output (2) of the F/F 3 rises to the 8th level, and transistors 1 to 41 constituting the switching circuit 4 are turned on (fired) (see (2)). That is, in the apparatus shown in FIG. 2, the ignition phase is fixed to the rising phase of the output pulse waveform (2) of the zero-cross detector 2.

On the other hand, this electric horn conversion device 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 calculates the voltage (@ Poetry 1f
i) into electric power (instantaneous value). In this case, the load voltage vs. power consumption horn curve of the load is expressed, for example, by the general formula w = vn, where n is 2 if the load is a pure resistor, and n is 2 if the load is a discharge lamp, and if the load is a discharge lamp or ballast. It is a value between 0, 5 and 1.5 depending on the type. The converter 6 is used by changing its characteristics to match such a curve depending on the load.

The integrator 7 receives the above-mentioned low 1 novel signal of the zero cross detection output (2) as a reset signal, and thereby integrates and outputs the load consumption voltage for each half cycle of the AC power supply voltage (2). This integral output ■ is supplied to one input terminal of the comparator 8.

The comparator 8 compares the reference voltage V refo 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 1 terminal of F/F3, F/1:3 is reset, and the output (2) becomes low level, thereby turning off the transistor 41. As a result, 1 to transistor 4
In other words, 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 yrerO. Therefore, in the device shown in FIG. 2, even if the power supply voltage fluctuates, constant power can always be supplied to the load every half cycle.

However, when using this type of phase control, as shown in Figure 4, a surge voltage is generated at a3 when the current is cut off due to extinguishing of the switching element. This has the inconvenience of having an adverse effect on other equipment, and in the worst case, destroying these equipment. This generation of voltage is due to the energy stored in the inductance component (1/2 - 1.s
This is because J2) is suddenly released as a 4-noge voltage when the current is interrupted.

(Object of the Invention) The present invention has been made in view of one problem with the conventional type described above, and is a so-called pre-amplifier that has an ignition phase a3 and an extinguishing phase in every phase and half cycle of the input AC power supply. Continuity/cutting) σ
In a phase control type power conversion device, JJ shown in Fig. 6:
In other words, the output setting value is changed by changing the firing phase φ1, and the extinguishing phase φ2 in the steady input state is changed to the firing phase φ1.
The load voltage and current in the latter half of the half-V cycle are set to be approximately constant values regardless of changes in the current, 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 constant output through feedback control, it is possible to control the surge voltage generated by cutting off the current during arc extinguishing, and to supply a stabilized output to the load every phase and half cycle. The purpose is to provide a power conversion device that is capable of

(Structure of the Invention) In order to achieve the above object, the present invention includes an AC power supply, a switching element that turns on and off every half cycle of the AC power supply, and supplies a phase-controlled LC output to a load; 33. The power conversion device includes means for accumulating the output amount H1'g for each of the phase and half cycles, and a control circuit for controlling the extinguishing phase of the switching element in accordance with the accumulated one value. The control circuit includes means for generating a variable first reference voltage, means for firing the switching element in a phase corresponding to the first reference voltage, and means for generating a fixed second reference voltage. a signal switching means for selectively supplying the output signal during the firing period of the switching circuit to the accumulating means and a predetermined waveform signal during the extinguishing period; The switching element is turned off when the reference voltage reaches a reference voltage of .

(Effects of the Invention) According to the present invention configured as described above, as shown in FIG. In addition, since this surge voltage is superimposed on a relatively low part of the AC power supply voltage, the peak value of the surge voltage that appears on the common wiring is reduced, It is possible to prevent the power conversion device of the present invention from adversely affecting other 1m devices connected in parallel to the common wiring or AC power source. In addition, the cumulative h that can be output
The switching element is turned off when the 1 value reaches a predetermined value, so even if the power supply voltage fluctuates or contains harmonics, constant power can always be supplied to the load every half cycle. can.

(Explanation of Examples) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 8 shows the configuration of a power conversion device according to an embodiment of the present invention. Further, FIG. 9 shows the operation time charts 1 to 1 of each part of the apparatus shown in FIG. 8 at J3(). Note that parts common or corresponding to those of the conventional example shown in FIGS. 283 and 3 are denoted by the same reference numerals.

The device shown in FIG. 8 differs from the device shown in FIG. A second comparison is made when the output of the triangular wave generator 10 exceeds the first reference voltage VreN, the voltage of which is varied by an external variable resistor (not shown) for output setting. The output terminal of the rectifier 2 is connected to the input terminal of the converter 6 via the analog switch 12. An analog switch 13 is connected in series between the rectifier 5 and the converter 6, and these analog switches 12 and 13 are turned on and off exclusively by the output 0 of the comparator 11. .For this, here:
The analog switch 12 is directly controlled by the output of the comparator 11, and the analog 1-1 switch 13 is controlled by the output of the comparator 11.
is controlled by the output @ which is inverted by the inverter 14.

FIG. 10 shows a specific circuit example of the device shown in FIG.

Note that at J5 in FIG. 10, a drive circuit 15 is connected between the flip-flop 3 and the switching circuit 4. In FIG. 10, the zero cross detector 2 compares the pulsating output ■ from the full-wave rectifier 'a1 with a predetermined threshold voltage vth, and detects a high level 10 crosses only near the zero cross of the AC power supply voltage ■. Output ■ is generated. The triangular wave generator 10 is composed of an integrating circuit 101 that integrates a predetermined DC voltage Vc, and a FET 102 that connects this integrating circuit 101, and generates a triangular wave voltage that repeats one half cycle of the AC power supply. ■Generates.

The comparator 11 compares this triangular wave voltage 0 with a first reference voltage ref1 generated at the operating terminal of the output setting volume 9, and the triangular wave voltage 0 is determined as the first reference voltage y ref.
When it exceeds l, a high level comparison signal ■ is generated. This comparison signal 0 is supplied to the cellar 1 to terminals of the F/F3. As a result, F/F3 is set, and the inverted output Q becomes a low level (inverted signal of ■).

Therefore, the transistor 151 of the drive circuit 15 is turned off, and the transistor 152 is turned on.
The primary winding 153p of switching circuit 4 is driven.
The main transistor 41 of the drive i~the secondary winding lli of the lance 153! The base current is supplied from 153s and it turns on.
Power ■ is supplied to the load. However, by changing the first reference voltage V refl, the firing phase angle φ1 can be changed freely.

Note that the diode 154 of the drive circuit 15 is for resetting the drive transformer 153. Also, switching In1f
Diodes 42, 43, 44. The series circuit 41 is a snubber circuit for protecting the main transistor 41.

By the way, J5 is a conventional device that performs constant output control.
In this case, if the ignition phase φ1 is moved backward as it is, the extinguishing phase φ2 will also be moved back along with the ignition phase φ1, making it impossible to perform dimming control smoothly. Therefore,
In the devices shown in FIGS. 8 and 10, the ignition phase φ1 remains unchanged in accordance with the first reference voltage, while the extinguishing phase φ2
In order to always have an arbitrary constant phase angle in the second half of the phase half-cycle, the integral of the feedback voltage ■ is not always from the firing phase φ1, but always from the falling phase φ of the zero-crossing pulse ■.
O's sea urchin starts. In this case, for the integral interval φ1 to φ2 involved in constant output control, the load power
, and for the section φ0 to φ1 before ignition, integrate the output (2) obtained by rectifying the AC power source (2) with the rectifier 1.

Specifically, two stages of analog switches () are connected to the input of the converter 6, and these analog switches 12 and 13 are turned on and off alternately. The control signal for the analog switches 12 and 13 uses the output pulse 0 of the ignition side comparator 11, and is connected to one of the analog switches 12 through an inverter 14. That is, when one analog switch is on, the other is off. As a result, the analog I switch 12 is turned on and the analog switch 13 is turned off during the phase period φO to φ1, and the output waveform (2) of the power source rectifier 1 is supplied to the converter 6. Further, in the period between phases φ1 and φ2, the analog switch 12 is turned off, the analog switch 13 is turned on, and the output waveform (2) of the load-side rectifier 5 is supplied to the converter 6.

The converter 6 performs polygonal line approximation to the input voltage according to the load, and generates a voltage (2) corresponding to the load power (instantaneous value). The integrator 7 is composed of an integrating circuit 71 that integrates the voltage 1, and an FET 72 that resets the integrating circuit 11. Then, this integration circuit 71 is reset when the FET 72 is turned on by the high-level zero cross detection output ■, and when the zero cross detection output ■ turns off (low level), the FET 72 is turned off and integrates the voltage ■. Start. Therefore, the integrator 7 integrates the load power when it is assumed that the power supply voltage ■ is supplied to the load in the phase φ0 to φ1 interval for every phase half cycle of the AC power supply,
After phase φ1, the actual load power is further integrated (
■).

[The comparator 8 compares the integral output ■ outputted from the integrator 7 with the second reference voltage Vrar2 set in the preset volume 16, and the integral output ■ becomes the second reference voltage v.
When it exceeds ref2, a comparison output ■ is generated and the signal is supplied to the ``/''3 hit terminal.This causes F / F 3
is reset, and the inverted output Q becomes high level. Therefore, the transistor 151 of the drive circuit 15 is turned on, the transistor 152 is turned off, the drive 1 lance 153 is deenergized, and the main transistor 41 of the switching circuit 4 is turned off (extinguished) because the supply of base current is stopped. In this way, in this device, even if the ignition phase angle φ1 is moved later according to the first reference voltage, the extinguishing phase angle φ2 can be fixed at the latter half of the phase half cycle. 1
It is possible to perform phase control, for example, dimming, in accordance with the reference voltage.

Furthermore, here, if it is assumed that there is no voltage fluctuation during load or no-load with respect to a predetermined input AC power supply voltage, the extinguishing phase will be constant no matter how the firing phase changes. However, in reality, there are power supply fluctuations, load fluctuations, etc., and when the output power () attempts to increase due to these fluctuations, the output of the integrator 7 reaches the second reference voltage Vrar2 more quickly, so the arc-extinguishing phase advances from φ2, thereby keeping the output constant.Also, when the output power ■ attempts to decrease, the extinction phase lags behind φ2, thereby keeping the output constant. In equipment, even if the power supply voltage fluctuates or contains harmonics, the power supplied to the load is always constant for each phase and half cycle.Therefore, as a load, for example, a lighting load (especially When using an electronic ballast (electronic ballast), it is possible to prevent fluctuations due to power supply voltage fluctuations and harmonics.In addition, the standard value of the extinguishing phase (at rated power supply voltage, etc.) can be set to a predetermined value unrelated to the ignition phase. Therefore, by shifting this extinguishing phase to a phase where the load current and voltage values are low in the latter half of every half cycle, it is possible to reduce the surge voltage and eliminate the negative influence on other equipment. can.

In J3 mentioned above, the power supply voltage is input to the converter 6 before the firing phase in the first half of the half-cycle, but when the integral output of the integrator 7 is It is also possible to apply a waveform that simply increases with respect to the phase.In this case, the extinguishing phase will generally change somewhat depending on the change in the firing phase, but this change By using this inversely, it is possible to modify the input/output characteristics of Riko's power converter.

[Brief explanation of the drawing]

Fig. 1 is a waveform diagram for explaining the conventional front conduction/cutoff phase control method, Fig. 2 is a block diagram of a conventional power conversion device, and Fig. 3 is a time diagram of each part of the signal in the device shown in Fig. 2. , FIG. 4 is a power supply voltage and output current waveform diagram of the device shown in FIG. 2, FIG. 5 is an equivalent circuit of the wiring system, FIG. 6 is a waveform diagram showing the operating principle of the present invention, and FIG. FIG. 8 is a block diagram of a power conversion device according to an embodiment of the present invention; FIG. 9 is a time chart of signals of various parts in the device of FIG. 8; FIG. 10 is a diagram showing a specific circuit example of the device shown in FIG. 8. 3...Flip-flop, 4...Switching circuit, 6...Converter, 7...Integrator, 8, 11...Comparator, 9...Reference voltage generation circuit, 10... - Triangular wave generator, 12, 13...analog switch, 16...preset volume. Patent Applicant Toshiba Electric Materials Co., Ltd. Agent Patent Attorney Tatsuo Ito Agent Patent Attorney Tetsuya Ito■ [Sou] ■ ■ [Sou] ■@

Claims (1)

[Scope of Claims] 1. An AC power supply, a switching element that turns on and off every half-cycle of the AC power supply to supply a phase-controlled output to the load, and an output every half-cycle of the above phase. In the power converter device, the control circuit includes means for accumulating the total value and adjusting the extinction phase of the switching element according to the accumulated value, the control circuit comprising means for generating a variable first reference voltage. and means for firing the switching element with a phase corresponding to a first reference voltage;
means for generating a fixed second reference voltage; and signal switching means for selectively supplying the output port signal during the firing period of the switching circuit and the predetermined waveform signal during the extinction period to the cumulative means. A power conversion device comprising: a power conversion device, wherein the switching element is turned off when the cumulative h1 value reaches the second reference voltage. 2. The accumulation h1 means includes means for converting a voltage value into a power value, and the switching means selectively supplies the AC power supply voltage and the output voltage to the converting means. The power conversion Fi4 device according to item 1.