JPH0923656A - Rectifier power supply - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To perform a high power factor operation by making an input current from an AC power source a sine wave and suppressing high-order harmonics, particularly third-order and fifth-order harmonics. A voltage reference E0 set by a voltage setter.
Is compared with the DC load voltage E, and the difference ΔE is amplified by the voltage control amplifier 15. The output is multiplied by the AC voltage signal v1 by the multiplier 16 and converted into an error signal .DELTA.v synchronized with the power supply phase. The error signal .DELTA.v is compared with the load AC current signal i1 detected by the current detector 13 by the comparator 17, and ON / OFF control of the power transistor 11 is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectifying power supply device that rectifies AC power and supplies DC power.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional structure of a rectifying power supply device for converting an AC power supply into a DC power supply by using a rectifier. In FIG. 4, an AC power supply 1 is rectified via a reactor 2 and rectifying elements 3 to 6 having a bridge structure, and supplies DC power to a load 8. Reference numeral 7 is a smoothing capacitor. in this case,
As shown in FIG. 5, the rectified current waveform id with respect to the AC voltage v becomes like a solid line when the reactor 2 is present,
When there is no reactor 2, it becomes like a dotted line and the reactor 2 improves the power factor. In addition, as shown in FIG. 6, the power supply current i has a fundamental wave i1, a third harmonic wave i3,
The fifth harmonic i5 is included.

[0003]

However, in the above-mentioned conventional rectifying power supply device, although the power factor is improved to some extent by the reactor, since it contains large harmonics, voltage distortion is caused and the power supply system is adversely affected. There is a problem.

In view of this problem, it is an object of the present invention to provide a rectifying power supply device with improved power factor and low harmonic content.

[0005]

To achieve the above object, the invention according to claim 1 is connected in series to a rectifying means for rectifying an AC voltage and outputting a DC voltage, and an AC input side of the rectifying means. A reactor, a capacitor for obtaining a DC voltage output from the rectifying means via a diode, a switch element for directly short-circuiting the DC output side of the rectifying means, and a deviation between a voltage reference and a DC voltage smoothed by the capacitor. Voltage control means for outputting a voltage control signal according to a value, current reference calculation means for calculating a product of a sinusoidal synchronizing signal synchronized with the AC voltage and the voltage control signal, and outputting a current reference signal; The AC reference current is compared with the AC side current of the rectifying means to output a drive signal for ON / OFF control of the switch element, and the AC input current is controlled in a sine wave shape. A DC output voltage and controlling a desired value while.

According to a second aspect of the present invention, an AC power supply, a filter means for filtering the AC power from the AC power supply, a reactor connected in series to the output side of the filter means, and an AC voltage from the reactor are provided. Rectifying means for rectifying and outputting a DC voltage, a capacitor for obtaining a smoothed DC voltage by applying the DC voltage output from the rectifying means through a diode, and a switch element for directly short-circuiting the DC output side of the rectifying means. A voltage control means for outputting a voltage control signal according to a deviation value between a voltage reference and a DC output voltage smoothed by the capacitor; and a sinusoidal synchronization signal synchronized with the AC voltage output from the filter means. Current reference calculating means for calculating a product with the voltage control signal and outputting a current reference signal, and detecting a current obtained through the reactor Current detecting means and comparing means for comparing the current reference signal with the detected current from the current detecting means and outputting a drive signal for on / off controlling the switch element. It is characterized in that the DC output voltage is controlled to a desired value while controlling the shape.

[0007]

FIG. 1 shows an embodiment of the present invention. In FIG. 1, a reactor 9, a capacitor 10, a power transistor 11, and a diode 12 are added to the conventional FIG.

Further, the voltage reference E0 set by the voltage setting unit 14 is compared with the DC load voltage E, the difference ΔE is amplified by the voltage control amplifier 15, and is 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 AC current signal i1 detected by the current detector 13 by the comparator 17, and ΔΔ
When v> i1, the logic output of the comparator 17 becomes "1" and the base drive circuit 18 of the power transistor 11
Power transistor 11 is turned on via
When it is 1, the logic output of the comparator 17 becomes "0" and the power transistor 11 is turned off.

When the power transistor 11 is turned on, the load side is short-circuited and the current i1 increases. When the power transistor 11 is turned off, the current i1 flows into the load side, that is, the diode 12, the capacitor 7 and the load 8 and decreases, and Δv> i1 is set to turn on the power transistor 11 again, whereby the power transistor 11 is turned on. , OFF are repeated at a switching frequency of several kHz determined by the delay element of the current control formed by the comparator 17.

Therefore, the current i1 pulsates at the switching frequency as shown in FIG.
This keeps the power factor at about 1 and almost eliminates the third and fifth harmonics.

Further, since the reactor 9 and the capacitor 10 are added, there is no drop in the power supply voltage due to the overlapping angle of the rectifier when only the reactor 2 is used,
The waveform distortion of the voltage signal v1 given as the synchronizing signal can be removed. In addition, as shown in FIG.
When combined together, it is possible to construct a rectification power supply device that uses a three-phase alternating current as a power supply and has a power factor of approximately 1.

[0013]

As described above, according to the present invention, a desired DC voltage can be stably obtained from an AC power source, and
The input current from the AC power supply can be a sine wave, and high-order harmonics, particularly the third and fifth-order harmonics can be suppressed, and high power factor operation can be performed.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a rectifying power supply device according to a first embodiment of the present invention.

FIG. 2 is a voltage and current waveform diagram of the rectifying power supply device according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of a rectifying power supply device according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional rectification power supply device.

FIG. 5 is a waveform diagram of voltage and current of a conventional rectification power supply device.

FIG. 6 is a current waveform diagram of a conventional rectification power supply device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply 2, 9 Reactor 3-6 Rectifying element 7, 10 Capacitor 8 Load 11 Power transistor 12 Diode 13 Current detector 14 Voltage setting device 15 Voltage control amplifier 16 Multiplier 17 Comparator 18 Base drive circuit

Claims (2)

[Claims] 1. A rectifying unit that rectifies an AC voltage and outputs a DC voltage, a reactor that is connected in series to an AC input side of the rectifying unit, and a capacitor that obtains the DC voltage output from the rectifying unit via a diode. A switch element that directly short-circuits the DC output side of the rectifying means, a voltage control means that outputs a voltage control signal according to a deviation value between the voltage reference and the DC voltage smoothed by the capacitor, and the AC voltage Current reference calculation means for calculating a product of a synchronized sine wave synchronization signal and the voltage control signal and outputting a current reference signal, and the switch element for comparing the current reference signal and the AC side current of the rectification means And a comparison means for outputting a drive signal for on / off control, and controlling the DC output voltage to a desired value while controlling the AC input current in a sine wave shape. Flow power supply. 2. An AC power supply, a filter means for filtering the AC power from the AC power supply, a reactor connected in series to the output side of the filter means, an AC voltage from the reactor is rectified and a DC voltage is output. Rectifying means, a capacitor for obtaining a smoothed DC voltage by applying a DC voltage output from the rectifying means via a diode, a switch element for directly short-circuiting the DC output side of the rectifying means, a voltage reference and the A voltage control means for outputting a voltage control signal according to a deviation value from the DC output voltage smoothed by a capacitor; a sinusoidal synchronization signal synchronized with the AC voltage output from the filter means; and the voltage control signal. Current reference calculation means for calculating a product and outputting a current reference signal, and current detection means for detecting a current obtained through the reactor Comparing the current reference signal with the detection current from the current detection means and outputting a drive signal for ON / OFF controlling the switch element, while controlling the AC input current in a sine wave shape. A rectifying power supply device characterized by controlling a DC output voltage to a desired value.