JPH0715960A - Power supply - Google Patents

Abstract

PURPOSE:To prevent damage to self arc-extinguishing control elements in controlling the phase of a load containing an inductance using the elements, by discharging energy accumulated in the inductance and controlling overvoltage applied to the self arc-extinguishing elements. CONSTITUTION:Main self arc-extinguishing control elements 4 and 5 and diodes 7 and 6 are connected together in series. The main self arc-extinguishing control elements are supplied with power from zero potential on a.c. voltage, and phase- controlled voltage is fed to a load. A series circuit is formed with self arc- extinguishing control elements 9 and 10 for flywheels that are turned on at the time of 'off' in phase control on the main self arc-extinguishing control elements 4 and 5, and flywheel diodes 11 and 12. The series circuit is connected in parallel with the load.

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 for controlling the phase of an AC power supply, such as a light control device used in a studio, a theater or a stage, a power supply for an electric furnace, a primary voltage control of a transformer, etc. Is.

[0002]

2. Description of the Related Art Conventionally, two thyristors connected in anti-parallel as a power supply device are connected in series with a load, and a control signal is given to the gate of the thyristor to switch the thyristor every half cycle of an AC input power supply. The load current was controlled in phase.

However, when the thyristor is switched, a large current change occurs per unit time, which causes noise. In addition, since the thyristor continues to turn on after the gate control signal is applied until the thyristor spontaneously commutates, the power utilization rate is poor.

Therefore, recently, as shown in FIG. 5, a bipolar transistor, MOSFET or IG having a self-extinguishing property.
There has been proposed a power supply device in which two sets of self-extinguishing control elements 4 and 5 such as BT and parallel circuits in which diodes 6 and 7 are provided in antiparallel with the control elements are connected in series in the reverse direction. When the control elements 4 and 5 are turned on by the drive signal from the drive device 14 when the AC power source 1 has a zero voltage, the load 2 is applied to the load 2 through the AC power source 1, the self-extinguishing type control element 4 and the diode 7, for example.
An alternating current is supplied as indicated by the solid line. Then, when the drive signal is changed from on to off at a predetermined phase of this half cycle, it can be made zero as shown in FIG. 6 (a). Further, after turning off the drive signal, the drive signal is output and the control element is turned on during this half cycle, the alternating current as shown by the solid line in FIG. 6B is supplied to the load. Thereby, the utilization rate of electric power can be improved.

[0005]

However, when the load is inductive such as a transformer, a fluorescent lamp, an induction coil, etc., the drive signal to the self-extinguishing control elements 4 and 5 is turned off to turn off the self-extinction. When the self-extinguishing control elements are turned off, the energy due to the load inductors stored when the self-extinguishing control elements are turned on is not released, an excessive oscillating voltage is generated, and the self-extinguishing control elements are damaged. There was something to do.

[0006]

According to the present invention, a main self-extinguishing type control element in which diodes are connected in series is energized from a zero potential of an AC power supply voltage, and a phase-controlled voltage has a load having an inductance component. In the power supply that supplies
A series circuit of a flywheel self-extinguishing control element and a flywheel diode that are turned on when the phase control of the self-extinguishing control element is turned off is provided in parallel with the output load.

The self-extinguishing control element is a self-extinguishing control element that performs high frequency chopping after phase control is turned off.

[0008]

[Operation] When the phase control of the main self-extinguishing control element is turned off, the self-extinguishing control element for the flywheel is turned on, and the energy accumulated in the inductance is passed through the self-extinguishing control element for the flywheel. To release.

Further, the main self-extinguishing type control element performs high frequency switching after the phase control is turned off to softly reduce the output current from the time when the phase control is turned off.

[0010]

1 is a block diagram of a power supply device according to a first embodiment of the present invention, and FIG. 2 is a waveform diagram of each part of the power supply device. In FIG. 1, 1 is an AC power supply and 2 is an inductive load, which is composed of an inductance component 2a and a resistance component 2b. Reference numeral 3 is a power supply device provided between the AC power supply and the load 2. The power supply device is provided with main self-extinguishing control elements 4 and 5 such as transistors, MOSFETs and IGBTs connected in series in opposite directions, and diodes 6 and 7 in opposite directions to the main control elements 4 and 5, respectively. ing. Self-extinguishing control elements 9 and 10 for flywheels such as transistors, MOSFETs and IGBTs connected in parallel to the load 2 in opposite directions, and self-extinguishing control elements 9 and 10 for flywheels, respectively, in opposite directions. Are provided with flywheel diodes 11 and 12. Also,
The main control elements 4 and 5 are driven by the drive signal of the main control element drive device 14, and the flywheel control elements 9 and 10 are driven.
Is driven by a drive signal of the flywheel control element driving device 15.

Next, the operation will be described. Now, when the potential of the A terminal of the AC power supply 1 is a half wave higher than the potential of the B terminal,
At the zero potential time of the AC power supply 1, the main control element drive device 14
A drive signal is input to the main control element 4 from this, the main control element 4 is turned on, and a current flows through the AC power supply 1, the main control element 4, the diode 7, the load 2, and the AC power supply 1. At this time, a voltage is generated in the inductance portion 2a of the load 2 in the direction of the arrow in FIG. 1, and energy is accumulated.

At time T1, the drive signal of the main control element drive device 14 is turned off as shown in FIG. 2 (b), and the flywheel control element drive device 15 is turned off as shown in FIG. 2 (c). A drive signal is output and the flywheel control element 10 is turned on. When the main control element 4 is turned off, a voltage in the direction opposite to the arrow in FIG. 1 is induced in the inductance 2a of the load 2, and a current flows through the load 2, the flywheel control element 10, the flywheel diode 11, and the load 2. Figure 2
As shown in (a), the voltage output from the power supply device 3 decreases due to the resistance 10 of the load and the resistance of the wiring. Next, at time T2, the drive signal of the flywheel control element driving device 15 is turned off, the flywheel control element 10 is turned off, a drive signal is output from the main control element driving device 14, and the main control element 4 is turned on. . As a result, a current flows through the AC power supply 1, the main control element 4, the diode 7, the load 2, and the AC power supply 1, and the output of the power supply device 3 rises as shown in FIG. Then, at time T3, the main control element 4 is turned off and the flywheel control element 10 is turned on. Less than,
This half wave is repeated until the output of the power supply device 2 becomes zero. The broken line in FIG. 2A shows the voltage waveform of the AC power supply.

Next, in a half wave in which the potential of the B terminal of the AC power source 1 is higher than the potential of the A terminal, the main control element driving device 14
Drive signal is input to the main control element 5 from the flywheel control element drive device 15 and the drive signal is input from the flywheel control element drive device 15 to the flywheel control element 9 so that the potential of the A terminal is higher than the potential of the B terminal. Performs the same operation. The main control element 5
Is ON, a current flows through the AC power supply 1, the load 2, the main control element 5, the diode 6, and the AC power supply 1. When the flywheel control element 9 is ON, the load 2, flywheel control is performed. A current flows through the element 9, the flywheel diode 12, and the load 2. As a result, the energy of the load inductance stored when the main self-extinguishing control element is turned on is released, and an excessive oscillating voltage does not occur at time T1.

When the load is a resistive load such as an incandescent lamp,
When the main control element is turned off, the current suddenly changes and vibrates, and a beat is apt to occur from the lamp and the wiring. FIG. 3 shows a second embodiment for softening the current when the main control element is turned off by such a resistance load. That is, FIG. 3 differs from FIG. 1 in that a small reactor 21 is provided between the flywheel portion 8 and the load 2. If there is a distance between the power supply device 3 and the load 2 and they are wound, the reactor 21 may not be required due to the inductance of the wiring. The operation of the power supply device of FIG. 3 is performed in the same manner as the power supply device of FIG.

FIG. 4 shows a third embodiment, in which a bridge type rectifying circuit of diodes 25 to 28 is provided in the power source line of the AC power source, and the main self-extinguishing type control element 2 is provided at the output of the rectifying circuit.
9 and flywheel diodes 31 to 3 in parallel with the load.
The bridge type rectifier circuit of No. 4 and the self-extinguishing control element 35 for flywheels are provided at the output of the rectifier circuit, and the number of control elements can be reduced. The operation of this device is similar to that of the power supply device of the first embodiment shown in FIG.

In the first to third embodiments, the flywheel control element is turned on when the main control element is off,
Further, although the main control elements 4 and 5 are turned off when the main control elements 4 and 5 are turned on and high-frequency chopping higher than the commercial power supply frequency is performed, the flywheel control elements 9 and 10 may be continuously turned on until the soft down time Tn. . In this case, when the main control elements 4, 5 are on, the flywheel control elements 9, 1
Even if the drive signal is input to 0, the potential of the output on the main control elements 4, 5 side is higher than the potential of the flywheel part, the reverse bias is applied to the flywheel diodes 11 and 12, and the current flows to the flywheel part. Not flowing. In addition, the main control elements 4, 5
When the soft-down at the time of turning off is rapidly performed, the period during which the flywheel control elements 9 and 10 are turned on is lengthened, and when the soft-down is performed gently, the period during which the main control element is turned on after time T2 is increased. It should be long.

[0017]

In the power supply device of the present invention described above, when the phase control of the main arc-extinguishing control element is turned off, the self-arc-extinguishing control element for the flywheel is turned on, whereby the inductance of the load is accumulated. Energy is not released through the self-extinguishing control element for the flywheel, so that an excessive oscillating voltage is not generated and the self-extinguishing control element is not damaged. In the case of resistive load, a small reactor is provided, and when the main self-extinguishing control element is off, the self-extinguishing control element for the flywheel is turned on, and the energy stored in the reactor is passed through the flywheel control element. It can be discharged by softening and can be prevented from beating due to load or vibration of wiring.

[Brief description of drawings]

FIG. 1 is a block diagram of a first embodiment of a power supply device of the present invention.

FIG. 2 is an output voltage waveform diagram of each part of the power supply device of FIG.

FIG. 3 is a block diagram of a second embodiment of the power supply device of the present invention.

FIG. 4 is a block diagram of a third embodiment of the power supply device of the present invention.

FIG. 5 is a block diagram of a conventional power supply device.

FIG. 6 is an output voltage waveform diagram of FIG.

[Explanation of symbols]

 1 AC power source 2 Load 2a Inductance component 2b Resistance component 3 Power supply device 4, 5, 29 Main self-extinguishing control element 6, 7, 25, 26, 27, 28 Diode 8 Flywheel part 9, 10 Self-extinguishing for flywheel Arc type control element 11, 12 Flywheel diode 14 Drive device for main control element 15 Control device drive device for flywheel 21 Reactor

Claims (2)

[Claims] 1. A main self-extinguishing type control element having diodes connected in series is energized from a zero potential of an AC power supply voltage,
In a power supply device that supplies a phase-controlled voltage to a load having an inductance component, a self-extinguishing control element for a flywheel and a flywheel diode that are turned on in parallel with an output load when the self-extinguishing control element is off. A power supply device comprising a series circuit. 2. The power supply device according to claim 1, wherein the self-extinguishing control element is a self-extinguishing control element that performs high frequency chopping after phase control is turned off.