JPH08149817A - Dc power supply device - Google Patents

Abstract

PURPOSE: To reduce high harmonic distortion content contained in an AC power supply current waveform by improving its continuity. CONSTITUTION: A DC power supply device is provided with a rectification circuit DS for performing the total-wave rectification of an AC power supply E voltage. It has a first diode D1 for applying the output voltage of the rectification circuit DS to a load D. It has a series circuit including an inductor CH1, a second diode D2, and a smoothing capacitor C which are connected between the output terminals of the rectification circuit DS. It has a switching element S1 for applying the output voltage of the rectification circuit DS to the inductor CH1. It also has a third diode D3 for applying the voltage of the smoothing capacitor C to the load L.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full-wave rectification type DC power supply device, and more particularly to reducing harmonic distortion seen from an AC power supply in the preceding stage of rectification.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional DC power supply device described in JP-A-59-148567. It looks like this: AC power supply E Rectifier circuit D for full-wave rectification of voltage
S includes a first diode D1 that applies the output voltage of the rectifier circuit DS to the load L, and a series circuit that includes an inductor CH1 and a smoothing capacitor C connected between the output terminals of the rectifier circuit DS. The third diode D3 for applying the voltage of 1 to the load L is provided.

[0003]

The apparatus shown in FIG. 6 has the following problems. The AC power supply E current is the sum of the current that directly flows to the load L through the first diode D1 and the current that charges the smoothing capacitor C through the inductor CH1. FIG. 7 shows an AC power supply E current input waveform of the apparatus of FIG. The figure (a) is an AC power supply E voltage waveform, and the figure (b) is an AC power supply E current waveform. As can be seen from (b), the conduction angle of the AC power supply E current is considerably wide, and the power factor is higher than that of the capacitor input type having only the smoothing capacitor C. However, the current does not flow in the phase angle region in which the instantaneous value of the AC power supply E voltage is low in (a). In this way, the AC power source E
There is no continuity of the current, and in this sense, the power factor is low and the harmonic distortion is large. It is an object of the present invention to provide a higher power factor type operation with less harmonic distortion.

[0004]

In order to reduce the harmonic components of the input current, it is important to improve the continuity of the AC power supply current as much as possible. In the present invention, even in the phase angle region where the AC power supply voltage instantaneous value is low, auxiliary means for flowing a current through the inductor is added to reduce the phase region in which the AC power supply current does not flow and reduce harmonic distortion. To do.

[0005]

In the DC power supply device of the present invention, a current flows through the inductor even in the phase angle region where the AC power supply voltage is low. Therefore, a series circuit of an inductor and a switching element is formed in a rectifier circuit that full-wave rectifies the AC power supply voltage,
The switching element is turned on in the phase angle region where the AC power supply voltage is low to guide the input current.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of FIGS. 1 and 2 according to the present invention will be described. AC power supply E Rectifier circuit D for full-wave rectification of voltage
Equipped with S. A first diode D1 that applies the output voltage of the rectifier circuit DS to the load L is provided. Inductor CH1 and second diode D connected between the output terminals of the rectifier circuit DS
2. A series circuit including a smoothing capacitor C is provided. A switching element S1 that applies the output voltage of the rectifier circuit DS to the inductor CH1 is provided. The third diode D3 for applying the voltage of the smoothing capacitor C to the load L is provided. AC power supply E
The voltage is rectified by the full-wave rectifier DS, and a part of its output current flows to the load L through the first diode D1. Part of the output current is inductor CH1 and second diode D2.
To charge the smoothing capacitor C. In the phase region where the voltage of the AC power supply E is low, the load L is fed from the smoothing capacitor C through the third diode D3. The above operation is similar to that of the conventional device shown in FIG. The feature of the apparatus shown in FIG. 1 is that a switching element S1 that intentionally increases the electromagnetic energy of the inductor CH1 is added. Switching element S1
Is provided with an input voltage detection circuit or a current detection circuit DET for controlling this. The operation of the switching element S1 will be described with reference to FIG. FIG. 2 is a waveform chart of each part of the apparatus shown in FIG. Among them, (a) is an AC power supply E voltage waveform.
(B) is a current waveform obtained by combining the current flowing through the first diode D1 and the current flowing through the inductor CH1, the second diode D2, and the smoothing capacitor C. (B) is the above-mentioned FIG.
The waveform is almost the same as that in (b). In the device of FIG. 1, the switching element S1 is turned on by selecting a phase angle region in which the voltage of the AC power supply E in which the current is zero in FIG. 2B is low, based on the signal detected by the input voltage detection circuit or the current detection circuit DET. Let Along with this, the current flowing through the switching element S1 has the waveform shown in FIG. Therefore, the AC power supply E current has a waveform of (d) which is a combination of (b) and (c). In the waveform (d), the continuity of the current is improved by eliminating the phase angle at which energization is stopped. This allows
Figure 1 The power factor seen from the AC power supply E of the device is high.
The harmonic distortion contained in the current is also small. FIG. 3 is a circuit diagram showing in detail a portion of the input voltage detection circuit DET of the device shown in FIG. The operation of this part is as follows. The transistor Q and the Zener diode ZD are used for controlling the driving of the switching element S1 (transistor). The instantaneous value of the sinusoidal waveform of the AC power supply E voltage decreases and the inductor CH1
The Zener diode ZD is set to be turned off when the phase region (low voltage region) in which the current flowing through the second diode D2 and the smoothing capacitor C is stopped. Then
The transistor Q is turned off at this time, and the switching element S1 is turned on. Since the driving power supply voltage of the switching element Q is the smoothing capacitor C, the switching elements Q and S1 continue to operate even if the instantaneous value of the AC power supply E voltage decreases. When the instantaneous value of the AC power supply E voltage rises again, the Zener diode ZD turns on, the transistor Q also turns on, and the switching element S1 turns off. The subsequent operation is the same as that of the conventional FIG. 6 device. FIG. 4 shows another embodiment of the device. The configuration is as follows. A rectifier circuit DS for full-wave rectifying the AC power supply E voltage is provided. A first diode D1 that applies the output voltage of the rectifier circuit DS to the load L is provided. Second switching element S3, second inductor CH2, second diode D2 connected between output terminals of rectifier circuit DS
A series circuit including a smoothing capacitor C is provided. The first switching element S2 for applying the output voltage of the rectifier circuit DS is provided in the series circuit of the second switching element S3 and the second inductor CH2. A third diode D3 for applying the voltage of the smoothing capacitor C to the load L is provided. Smoothing capacitor C
A first inductor C for applying the output voltage of the rectifier circuit DS to the
With H1. In the apparatus of FIG. 4, in addition to the first inductor CH1 similar to CH1 of FIG. 1 for charging the smoothing capacitor C, a high frequency chopper circuit including a second inductor CH2 and a second switching element S2 is attached. The operation of the apparatus shown in FIG. 4 will be described with reference to FIG. FIG. 5 is a waveform chart of each part of the apparatus shown in FIG. Among them, (a) is an AC power supply E voltage waveform. (B)
Is the current flowing through the first diode D1 and the first inductor C
It is the current waveform which combined the current which flows through H1 and the smoothing capacitor C. This corresponds to FIG. 2 (b). Similar to the device of FIG. 1, the first switching element S2 is subjected to high-frequency switching operation only in the phase angle portion in which the current of the current waveform (b) is stopped by the signal detected by the input voltage detection circuit or the current detection circuit DET. 2 The switching element S3 is turned on. At this time, the second inductor CH
2. The first switching element S2 and the second diode D2 operate as a high frequency boost chopper circuit to charge the smoothing capacitor C. The current waveform associated with the charging is as shown in (c). A waveform (d) is obtained by combining (c) with (b). The waveform (d) corresponds to the AC power supply E current. Therefore, as in the device of FIG. 1, the power factor is high and the distortion is low. The waveform (d) is after the high frequency component of the waveform (c) is removed via the low-pass filter LF shown in FIG. Since the switching element S1 in FIG. 1, the switching elements S2 and S3, and the second inductor CH2 in FIG. 4 operate in the phase angle region where the AC power supply E voltage instantaneous value is low, the capacitance of each of these elements is relatively small. The small ones are in time.

[0007]

According to the present invention, the continuity of the AC power supply current is enhanced, the harmonic components contained therein can be reduced, and the power factor is increased.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the device of the present invention.

[Fig.2] Operation waveform diagram

FIG. 3 is a detailed circuit diagram of the circuit shown in FIG.

FIG. 4 is a circuit diagram of another embodiment device.

[Fig. 5] Operation waveform diagram

FIG. 6 is a circuit diagram of a conventional device.

[Fig. 7] Operation waveform diagram

[Explanation of symbols]

E: AC power supply, DS: full-wave rectifier, D1: first diode, D2: second diode, D3: third diode, C
H1: inductor or first inductor, CH2: second inductor, C: smoothing capacitor, L: load, S1:
Switching element, S2: First switching element, S
3: Second switching element

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[Procedure amendment]

[Submission date] April 27, 1995

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

FIG.

[Figure 3]

[Fig. 2]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

Claims (2)

[Claims] 1. A second inductor comprising a rectifier circuit for full-wave rectifying an AC power supply voltage, a first diode for applying an output voltage of the rectifier circuit to a load, and an inductor connected between output terminals of the rectifier circuit. A series circuit including a diode and a smoothing capacitor is provided, a switching element that applies the output voltage of the rectifier circuit to the inductor is provided, and a third diode that applies the voltage of the smoothing capacitor to the load is provided. DC power supply. 2. A second switching element comprising a rectifier circuit for full-wave rectifying an AC power supply voltage, comprising a first diode for applying an output voltage of the rectifier circuit to a load, and being connected between output terminals of the rectifier circuit. A second inductor, a second diode, a series circuit including a smoothing capacitor, a second switching element, a first switching element that applies the output voltage of the rectifier circuit to the series circuit of the second inductor, and the smoothing circuit. A DC power supply device comprising a third diode for applying the voltage of a capacitor to the load, and a first inductor for applying the output voltage of the rectifier circuit to the smoothing capacitor.