Soft-switch three-phase PWM rectifier with auxiliary free-wheel channel

Abstract

The invention discloses a soft-switch three-phase PWM (Pulse Width Modulation) rectifier with an auxiliary free-wheel channel. The soft-switch three-phase PWM rectifier comprises a three-phase bridge arm consisting of 6 total-control main switches respectively provided with antiparallel diodes and parallel capacitors, input filtering inductors connected between the middle points of each phase of bridge arm and an AC power grid, and an output capacitor connected to the output terminal of the three-phase bridge arm, wherein the total-control switches with both the antiparallel diodes and the parallel capacitors are connected or not connected to two ends of the three-phase bridge arm; an auxiliary switch with both antiparallel diodes and parallel capacitors is connected between a DC bus and the output capacitor of the three-phase bridge arm; and resonance branch circuits consisting of both resonance inductors and clamping capacitors are connected to two ends of the auxiliary switch in a bridging manner. The soft-switch three-phase PWM rectifier has a simple structure, and can inhibit reverse restoration of diodes and reduce electromagnetic interference. All switch devices of the rectifier achieve zero-voltage switch-on, have small loss and high circuit efficiency, facilitate improving the operating frequency and further improve the power density. The rectifier provided by the invention realizes output capacity and voltage control and achieves the power factor correction function of input current.

Description

technical field [0001] The invention relates to a rectifier, especially a soft-switching three-phase PWM rectifier with additional freewheeling path. Background technique [0002] Current three-phase PWM rectifiers such as figure 1 As shown, it consists of six fully controlled main switches S with anti-parallel diodes 1 ~S 6 The three-phase bridge arms formed are respectively connected to the output filter inductance L between the midpoint of each phase bridge arm and the AC grid a ~ L c And the output capacitor C connected to the output terminal of the three-phase bridge arm o . This kind of three-phase rectifier can realize input current power factor correction, but the circuit works in a hard switching state, there is a problem of reverse recovery of the diode, and the switching loss of the device is large, which limits the improvement of the operating frequency, reduces the circuit efficiency and has a large electromagnetic interference. Contents of the invention...

AI Technical Summary

Problems solved by technology

This kind of three-phase rectifier can realize input current power factor correction, but the circuit works in a hard switching state, there is a problem of reverse recovery of the diode, and the switching loss of the device is large, which limits the improvement of the operating frequency, reduces the circuit efficiency and has a large electromagnetic interference

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