JPS59198873A - Rectified power source circuit - Google Patents

Abstract

PURPOSE:To suppress the production of harmonic waves by controlling ON, OFF a switching element for shortcircuiting the output of a rectifier by multiplying the difference between an output voltage and a set voltage by a power source voltage signal and further comparing it with a current waveform. CONSTITUTION:A rectifier having rectifying elements 3-6 connected in a bridge through reactors 9, 2 and a capacitor 10 is connected to an AC power source 1, a transistor 11 for shortcircuiting the output is further provided at the output side of the rectifier to supply a DC power to a load 8. The output voltage is compared with the voltage of a setter 14, the difference is multiplied by a multiplier 16 by the AC voltage signal to obtain an error signal DELTAv synchronized with the power source phase, compared by a comparator 17 with a load AC current signal, thereby controlling the transistor 11. Accordingly, the AC current is pulsated in a switching frequency to be synchronized with the power source voltage, power factor is held at 1, and the third and fifth harmonic waves can be almost eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a rectifier power supply circuit 42 or 9 that rectifies AC power supply voltage and supplies DC voltage, and particularly relates to a circuit for suppressing two source harmonics. It is something.

[Technical background of the invention and its problems]

The conventional configuration of a power supply circuit that uses a rectifier to convert AC power to DC power is shown in Figure 1 (2).

In FIG. 1, an AC power source 1 is rectified via a reactor 2 and rectifying elements 3 to 6 in a bridge configuration, and a load 8 (
''--supplies DC power. 7 is a smoothing capacitor.

In this case, as shown in Figure 2 (=), the rectified current waveform id for AC heavy pressure V becomes 4 as shown by the solid line when reactor 2 is present, and 4 as shown by the dotted line when reactor 2 is not present. Power factor improvement by 2C2 is performed.

In addition, as shown in Figure 3 (2), the Shiyuantun stream i has a fundamental wave i8
, third harmonic i3, and fifth harmonic i.

In other words, in the conventional rectifying power supply circuit shown in Figures 1 and 2, the power factor is improved to some extent by the reactor, but since it contains large harmonics, it causes voltage distortion, which has a negative effect on the power supply system. .

[Purpose of the invention]

It is an object of the present invention to provide a rectifier circuit with improved power factor and low harmonic content.

[Summary of the invention]

The present invention is based on a rectifier power supply circuit that rectifies an AC power source into a DC power source, connects a switching element that short-circuits the output side of the rectifier (two rectifier outputs), and also connects a switching element that short-circuits the output of the rectifier, and A voltage control circuit is provided which compares the synchronization error signal waveform obtained by multiplying the voltage signal of the AC power supply by the voltage signal of the AC power supply and the first waveform, and turns on and on the switching element according to the polarity of the difference. (This prevents the generation of second harmonics.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIG.

In FIG. 4 (2), a reactor 9, a capacitor 10, a power transistor 11, and a diode 12 are added compared to the conventional device shown in FIG. 1 (2).

Furthermore, the voltage reference E set by the pressure setting device 14 is compared with the DC load voltage E, and the difference ΔE is amplified by the voltage control amplifier 15 and multiplied by the AC voltage signal v1 by the multiplier 16. It is converted into an error signal ΔV synchronized with the power supply phase.

The error signal ΔV is compared with the load alternating current signal 11 detected by the first-class detector 13 in the comparator 17, and when pv>it, the logic output of the comparator 17 becomes 1, The power transistor 11 is turned on via the base drive circuit 18, and when Δv < L, the logic output of the comparator 17 becomes 1'' and the power transistor 11 is turned on.
Turn off.

When the power transistor 11 is turned on, the load side is short-circuited and the current i□ increases.When the power transistor 11 is turned off (2), the current i is the load side, that is, the diode
Capacitor 7 and load 8 ζ2 flow decrease, Δv
>i, the power transistor 11 is turned on again, and thus the power transistor 110 is turned on and off repeatedly at a switching frequency of several kHz determined by the IE current control delay element formed by the ratio device 17.

Therefore, the current 11 pulsates at the switching frequency as shown in FIG.

Harmonics such as the 5th order are almost eliminated.

In addition, since reactor 9 and capacitor 10 are added, there is no drop in the power supply voltage due to the overlapping angle C2 of the rectifier when only reactor 2 is used, and the waveform distortion of voltage signal v1 applied as a synchronization signal is reduced. Can be removed.

Next (= Fig. 6 shows another embodiment of the present invention.

In FIG. 6, a DC reactor 19 is inserted on the rectified output side (2) in place of the reactor 2 in FIG.

In this case, current control is performed on the rectified output side, and the other aspects are the same as in the case of FIG. 4.

Furthermore, as shown in FIG. 7 (2), by combining three sets of single-phase rectifier circuits, a rectifier source circuit with a power factor of 1 using three-phase alternating current as a power source can be constructed.

〔Effect of the invention〕

As explained above (-1) According to the present invention (2), a rectifier power supply circuit that rectifies AC to supply DC power (2) sets the power factor of AC power (2) to 1 (2) and (double harmonics). The occurrence of can be suppressed.

[Brief explanation of drawings]

Figure 1 is a diagram showing the general configuration of a conventional rectifier power supply circuit.
Figures 2 and 3 are diagrams showing voltage and current waveforms;
FIG. 4 is a circuit diagram showing one embodiment of the present invention, FIG. 5 is a direct voltage and first waveform diagram thereof, and FIGS. 6 and 7 are circuit diagrams showing other embodiments of the present invention, respectively. . 1 Alternating current source 2.9 Reactor 3 to 6 Laminar flow element 7.10 Capacitor 8 Load 11 Power transistor 12 Diode 14 Voltage footer 15 Voltage regulator i+, 11 amplifier 16
Multiplier 17 Comparator 18 Base drive circuit 19 @flow reactor

Claims (1)

[Claims] A rectifier power supply circuit that rectifies an AC power source to create a DC power source (2) A switching element is connected to the output side of the rectifier (2) to short-circuit the output of the rectifier (2) the difference between the DC output voltage and the set voltage (2) A rectifier power supply circuit comprising a voltage control circuit that compares a synchronization error signal waveform multiplied by a voltage signal of a two-current voltage source with a current waveform and turns on and off the switching element according to the polarity of the difference.