A rectifier and its control method

Abstract

The invention discloses a rectifier and a control method thereof, and belongs to the technical field of high power factor rectification. The rectifier comprises a three-phase voltage source circuit (1), a three-phase uncontrolled rectification circuit (2), two symmetric boost circuits (3), a third harmonic voltage generation circuit (4) and an H-bridge boost power factor correction (PFC) circuit (5), wherein double half-wave boost PFCs respectively generate steamed bread wave phase current waveforms at 30-150 degrees and 210-330 degrees within a period, a waveform compensation circuit can be switched to the corresponding phase when a certain phase current lacks, the phase current waveform which is insufficient is compensated, so that an input current is changed to a standard sine wave, and a converter works in a unit power factor rectification state. The rectifier can be used for a three-phase AC / DC conversion circuit having the PFC function, and the topological structure is simple and is convenient to control and easy to implement.

Description

technical field [0001] The invention relates to a rectifier and a control method thereof, belonging to the technical field of high power factor rectification. Background technique [0002] Power Factor Correction Technique (Power Factor Correction Technique) is a basic technology in the field of power electronics and industry. It is used to suppress harmonic pollution and reduce the harm caused by high-order current harmonics to the power grid and various electrical equipment. With the increase of electrical equipment, the requirements of high efficiency, high power density and high power factor are also put forward for the power converter. Therefore, various new PFC conversion topologies have also emerged as the times require. [0003] There are two types of power factor correction technology: passive power factor correction and active power factor correction. Passive power factor correction uses passive components, such as LC filters. Although the circuit structure is sim...

AI Technical Summary

Problems solved by technology

Three-phase single-switch Boost PFC circuit, in order to achieve decoupling between the three phases, three inductors are placed on the AC side, and work in the current discontinuous mode, which is characterized by simple current control, but the input and output current of the circuit The ripple is large, the filter current is high, and the output voltage is too high, which brings certain difficulties to the selection of the power tube. This circuit is generally used for output power less than 10kw and for current THD ((totalharmonic distortion, total harmonic distortion) Wave distortion)) occasions where the requirements are not strict

Although the three-phase multi-switch can control the input current with high precision and obtain excellent performance, it requires a large number of switching tubes, complex driving and control strategies, and high cost. It is suitable for high-power applications.

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