JPH08308229A - Distortionless rectifying circuit - Google Patents

Abstract

PURPOSE: To eliminate the low power factor and the waveform distortion by inserting a choke coil to the AC input side of a multiple rectifier and setting the coil to a resonance value. CONSTITUTION: A quadruple full-wave rectifier 2 and a resonance value choke coil 1 are combined. A smoothing capacitor 3 is connected. For example, a power factor is 0.997, and a distortion factor is about 2%. The power factor of the rectifier 2 approximates 1. Accordingly, the distortion factor is small. This is held in the wide range of the output current. This range changes according to the combination of the L and the C to satisfy the resonance condition. The capacity of an apparatus increases for a large current.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a rectifier circuit for converting alternating current into direct current at a high power factor.

[0002]

2. Description of the Related Art There are a capacitor input type rectifier circuit, a circuit in which a choke coil is added thereto, and a high frequency switching system such as an active filter.

[0003]

The problem is to eliminate the low power factor and waveform distortion, which are inevitable in conventional rectifier circuits, without using a high-frequency system which has problems in noise and cost.

[0004]

The problem is solved by putting a choke coil (capacitance L) on the AC input side of the multiple voltage rectifier circuit and setting L to a resonance value. The choke coil shall not be placed on the DC output side as usual. When placed on the AC input side, it is found that the multiple voltage rectifier circuit is quasi-equivalent to the capacitor (capacitance C), that is, the input current waveform is close to the advanced sine wave. The resonance value is a value at which L and C resonate in series with the input frequency. The actual work is just adjusting L or C so that the current waveform matches the voltage phase, and can be easily done on the personal computer screen with the circuit simulator. The value of C is close to the value of the first-stage condenser of the multiple voltage rectifier circuit. Higher power factor can be reached as the number of pressure doublers increases. The need for a slight resistance on the input line and a smoothing capacitor on the output side is the same as in conventional rectifier circuits. The simulator puts them in the calculation. Multi-phase rectification cannot be achieved simply by multiplexing a single-phase circuit. Inter-phase short circuit due to capacitors must be prevented. In the rectification in the connection method shown in FIG. 4, the number of phases and the number of pressure-doubled stages can be arbitrarily set, and the number of pressure-doubled stages is not the same for the upper and lower arms. Further, if a switch element is inserted in the diode position of the rectifier circuit and the reverse flow of current is performed at the same timing as during rectification, direct current is converted to alternating current.

[0005]

Function: The power factor of this rectifier circuit is close to 1. Therefore, the distortion rate is also small. It is also maintained over a wide range of output current. This range differs depending on the combination of L and C that satisfy the resonance condition.
For large current, the device volume becomes large.

[0006]

Example 1 is shown in FIG. Combination of quadruple pressure double wave rectification circuit and resonance value choke coil. Connect a smoothing capacitor. The power factor is 0.997 and the strain rate is about 2% (measured by Kazuhiro Sato, Department of Electrical Engineering, Kagoshima University in 1994).

Example 2 is shown in FIG. Combination of double voltage double wave rectification circuit and resonance value choke coil. Connect a smoothing capacitor. Power factor 0.95.

[Third Embodiment] FIG. 3 shows a combination of a three-phase voltage doubler rectifier circuit, three resonance value choke coils, and a smoothing capacitor.

[0007]

The low power factor problem of the rectifier circuit has been solved. It is possible to prevent the distortion of the waveform of the input system.

[Brief description of drawings]

FIG. 1 is a first embodiment of a distortionless rectifier circuit.

FIG. 2 is a second embodiment of a distortionless rectifier circuit.

FIG. 3 Example of three-phase distortionless rectifier circuit

FIG. 4 Multi-phase / multi-voltage rectifier circuit

[Explanation of symbols]

 1 Resonance value choke coil 2 4 Double voltage double wave rectifier circuit 3 Smoothing capacitor 4 Double voltage double wave rectifier circuit 5 Three phase double voltage rectifier circuit

Claims (6)

[Claims] 1. A rectifier circuit formed by connecting a choke coil having an AC input having a resonance value and a multiple voltage rectifier circuit. 2. The rectifier circuit of FIG. 1 within the scope of claim 1. 3. The rectifier circuit of FIG. 2 within the scope of claim 1. 4. A rectifier circuit formed by coupling a choke coil having an AC input having a resonance value and a multi-phase multi-voltage rectifier circuit as shown in FIG. 5. The inverter circuit according to claim 1 or 4, wherein the rectifier circuit has a switch element at a diode position. 6. A multi-phase, multi-voltage rectifier circuit as shown in FIG.