JPH0284069A - Dc power device - Google Patents

Abstract

PURPOSE:To prevent increase of switching loss and generation of noise by driving a switching element of a main circuit with a voltage comparator having a hysteresis characteristic of a proportional value and a multiplication signal of the absolute value of the current through a choke coil in the main circuit. CONSTITUTION:As compared with a reference sinusoidal wave voltage Vr by a comparator 8, a switching element 4 is driven when the current proportional value vii gets to the reference sinusoidal wave voltage Vr, if t=t1. If t=t2, and when the current proportional value vii gets to the reference sinusoidal wave voltage Vr, the drive of the switching element 4 is interrupted. In the area where the switching element 4 is ON, energy is accumulated to a choke coil 3. With the element 4 OFF, the energy accumulated to the choke coil 3 is released to a load RL through a flywheel diode 5. By switching this element 4, the input current waveform is to be a continuation of high frequency triangular waveform. The envelope of a current drop value and that of a current peak value will respectively be sinusoidal waves.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention transforms the input current into an approximate sine wave, thereby
A DC power supply that can obtain a controlled output voltage by reducing the harmonic components of the input terminal and using a power factor tool! J
Regarding location.

[Conventional technology]

For a DC power supply device that obtains DC output from an AC power supply, simply using a rectifier is not preferable because the input current waveform is intermittent and the power factor and efficiency are low. Therefore, a DC power supply device is known that reduces harmonic components at the input terminal and improves the power factor by converting the input current into an approximate sine wave.
For example, there is one shown in FIG. To explain according to this diagram, input AC voltage is received from input terminals 10 and 11.

A pulsating current is obtained by the rectifier circuit 2 via the line filter 14. This pulsating voltage is connected to the switch element 4 via the choke coil 3I. This switch 1 element 4 repeatedly turns on and off, and when it is off, the energy of the chiroke coil 31 is transferred to the output terminal 12 via the flywheel diode 5.
．． Sent to 13, load 1? A DC output voltage is generated at L.

Here, the pulse tIL'fIi pressure is obtained by multiplying 57 by the value υ0 obtained by amplifying the error between the value υi divided by the resistors 5R1 and R2, the output voltage, and the reference voltage source 16 by the error amplifier 56, as the reference sine wave voltage Vr. , this reference sine wave voltage Vr can be controlled in amplitude v4 depending on the load condition, and the current proportional value layer of the switching element 4 detected by the zero-order resistor 5R3, which enables energy control, is converted to the reference sine wave voltage by a comparator 8. When the current proportional value υt4 reaches the reference sine wave voltage ν, the switching element 4
cut off the drive. When the energy of the choke coil 31 is released, the coil voltage becomes zero. The state is detected by the secondary detection winding of the Chiroku coil 31, and 9! The flip-flop circuit 9 in the dynamic stage is operated to drive the switch element 4. By switching the switch element 4 in this manner, the input terminal is shaped into a triangular waveform as shown in FIG. 4, a half cycle of which is shown.The waveform of the 0-input alternating current is a high-frequency triangular wave, with the envelope of the peak value being a sine wave. A sinusoidal waveform is obtained by attenuating the modulated frequency component by the line filter 14.

[TSM that the invention aims to solve]

However, in such a conventional DC power supply, the current in the choke coil becomes a triangular wave from zero to the peak value in each switching cycle, so the choke coil current, switch element current, and flywheel diode current Each peak value is AC input current 11
This increases switching loss and tl
There was a problem of increased occurrence of fP.

[Means to solve the problem]

The present invention aims to solve five or more problems.

A means for obtaining a differential voltage between a proportional value of the voltage of the load and a reference voltage, and a means for multiplying by a proportional value of the absolute value of the voltage of the 5-input AC power supply, and a proportional value of the absolute value of the current of the choke coil of the main circuit is provided. and the above-mentioned multiplication signal are used to drive the switching elements of the main circuit using a voltage comparator having a history characteristic.

[Effect]

Therefore, by means of obtaining the difference voltage between the proportional value of the voltage of the five loads and the reference voltage, a control signal corresponding to a desired output setting value can be obtained. Then, by means of multiplying the absolute value of the voltage of the input AC illumination by a proportional value.

A reference sine wave voltage whose amplitude can be controlled is obtained. and,
Compare the voltage proportional to the current magnitude of the Chirok coil in the main circuit with its reference sine wave voltage.

A voltage comparator having a hysteresis width approximately proportional to the reference sine wave voltage drives the switching element of the main circuit so as to limit the current variation width of the choke coil within the hysteresis width.

〔Example〕

FIG. 1 is a connection diagram of an embodiment of the DC type m device according to the present invention. In the figure, an input AC voltage is received from an input terminal 10.11, and a pulsating voltage is obtained by a rectifier circuit 2 via a line filter 14. This pulsating voltage is connected to a switch element 4 via a choke coil 3. This switching element 4 repeats on and off at a frequency much higher than the frequency of the input AC, and when it is on, the choke coil 3
When the choke coil 3 is off, the energy of the choke coil 3 is sent to the output terminal 12.13 via the flywheel diode 5, generating a DC output voltage at the load RL. A capacitor C1 connected in parallel to the output terminals 12,13 has a smoothing effect on the switching frequency.

Here, the pulsating voltage that is the output of the rectifier circuit 2 is generated by the resistance raρ1
．． l? The value υ0 obtained by amplifying the error between the value υ1 divided by 2, the output voltage, and the reference voltage source 16 by the error amplification S6 is extracted as the reference sine wave voltage Vr by the multiplier 7. This reference sine wave voltage Vr is set in the load state. The proportional value of the input current current*li detected by the zero-order current transformer 1 is obtained through the rectifier circuit 15 to obtain its absolute value, and the absolute value is obtained through the rectifier circuit 15. A corresponding voltage υ11 is generated across the device 126.

This voltage value is connected to resistors R7, R8, R9 and comparator 8.
Thus, a hysteresis width approximately proportional to the AC input voltage value υ1 is created, and the drive output signal transitions at a threshold within the hysteresis width. That is, the comparator 8 compares it with the reference sine wave voltage Vr, and when the current proportional value V reaches the reference sine wave voltage Vr at t=tl, for example, as shown in FIG. 2, the switching element 4 is driven. =
When the current proportional value vt+ reaches the reference sine wave voltage Vr at t2, the driving of the switching element 4 is cut off. Energy is accumulated in the choke coil 3 in the section where the switch element 4 is on.

When the switch element 4 is turned off, the energy applied to the choke coil 3 is released and supplied to the load RL via the flywheel diode 5.

By switching the switch element 4 in this manner, the input terminal waveform becomes a continuous high-frequency triangular waveform, and the envelope of the 'R current drop value and the envelope of the current peak value each become a sine wave.

Therefore, t=0. which corresponds to the valley point of the AC input waveform.
The switching frequency near t=7/2 is higher than the switching frequency near the peak of the waveform, t=t2.

Since the waveform of each cycle is a triangular wave, the average value of the input AC current 1i is the peak value of 172, which is a sine waveform, and is 1
By attenuating the modulation frequency component using an input filter, the high frequency component is reduced and the power factor is also improved.

If the value of the resistor FXSR9 is sufficiently large compared to the values of the resistors R1 and R8, the above-mentioned hysteresis will occur, but the resistor i! As the value of SR9 becomes smaller, the width of the hysteresis in the waveform shown in Figure 2 becomes proportional to the input AC voltage waveform. The switching frequency near 0.t·d/2 and the switching frequency near the peak L=12 of the waveform are close to the same.

The current detection means is not limited to the current transformation Di, but any other method may be used as long as the current in the choke coil 3 can be detected.For example, a method of inserting a low resistance in series with the choke coil 3 may be used. In addition, the current ■3 of the choke coil 3 is connected to the switch element 4.
Since the current 14 is the sum of the current 14 of the flywheel diode 5 and the current 5 of the flywheel diode 5, a DC transformer or a low resistance may be inserted into each of the choke coil 3 and the switch element 4 and their signals may be added.

The voltage detection means can also be obtained directly from the input terminal 10.11 via the M flow path. In that case, it is necessary to insert a small transformer or an optical coupling element between them as an insulating means.

The circuit diagram shown in FIG. 1 is one embodiment, and the same effect can be achieved by switching the polarities of the rectifying circuit 2, the switching element 4, and the flywheel diode 5.

And if the flywheel diode 5 is a unidirectional switching element.

In addition to a normal diode, a Schottky diode may be used, and the switch element 4 may be a field effect transistor, a bipolar transistor, an IGBT, or the like.

〔Effect of the invention〕

Since the present invention has the above-mentioned features, the effective current and di/dt of the switching element, Chittark coil, flywheel diode, and input line filter in the DC power supply device are reduced, and each loss is reduced. Noise is also reduced, and the power factor and efficiency are improved. Since each reactive power is reduced, the rating of the main circuit components can be lowered, which is economical.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the DC power supply device according to the present invention, and f
Figure I42 shows a waveform diagram of each part to explain the operation of the device shown in Figure 1, Figure 3 shows a circuit diagram of a conventional direct I11 power supply, and Figure 4 shows a diagram of the circuit shown in Figure 3. The operating waveforms are shown. l...variable ml 2...rectifier circuit 3...
・Choke coil, 4... Switch element 5...
Flywheel diode 6...error amplifier, 7...multiplier, 8...comparator 9...flip-flop circuit 10, ll...input terminal 12.13...output terminal 14...line Filter, 15... Rectifier circuit 1
G... Reference voltage source 5 CI... Capacitor [1l-R9... Resistor. RL...Load

Claims (1)

[Claims] A double-wave rectifier connected to an input AC power supply, a choke coil connected to the output of the double-wave rectifier, a switching element connected to the choke coil, and a unidirectional switching element connected to the choke coil. A DC power supply device that supplies DC power to a load via a DC power source, comprising means for multiplying a difference voltage between a proportional value of the voltage of the load and a reference voltage by a proportional value of the absolute value of the voltage of the input AC power supply. , wherein the switching element is driven by a voltage comparator having a history characteristic between a proportional value of the absolute value of the current of the choke coil and the multiplication signal.