Unified power quality regulator based on soft switching circuit

Abstract

The invention discloses a unified power quality regulator based on a soft switching circuit. At an input side, three half-bridge arms form a three-phase current converter circuit, which is connected in series with a three-phase power grid through an LC filter and a transformer. At an output side, the other three half-bridge arms form a three-phase current converter, which is connected to a power grid at a load end through an output filter inductor. Each half-bridge arm is composed of two main switch transistors connected in series in the vertical direction. A resonant branch consisting of an auxiliary switch transistor, a clamping capacitor, and a resonant inductor is connected between the positive and negative common buses of the six half-bridge arms. Resonant capacitors are connected inparallel with the main switch transistors and the auxiliary switch transistor. The driving pulse signal of the auxiliary switching transistor is synchronized with the driving pulse signal of the mainswitching transistor. The unified power quality regulator can realize zero-voltage turning on of all switching transistors in each switching period, suppresses the reverse recovery current of the mainswitch anti-parallel diode, is low in switching loss and high in circuit efficiency, contributes to increasing the switching frequency and increases system power density.

Description

technical field [0001] The invention relates to the technical field of a unified power quality regulator, in particular to a unified power quality regulator based on a soft switching circuit. Background technique [0002] The traditional unified power quality regulator circuit includes three-phase converters on the input side and three-phase converters on the output side. Each set of three-phase converters is composed of three half-bridge arms and three sets of filters; each set of bridge The arm is composed of two series-connected fully-controlled main switching tubes containing anti-parallel diodes; the input-side three-phase converter is connected in series between the three-phase grid and the load through a transformer; the output-side three-phase converter is directly connected to the three-phase phase load; the positive and negative DC buses of the two sets of three-phase converters are connected to each other to form a positive and negative public DC bus, which are re...

AI Technical Summary

Problems solved by technology

The traditional unified power quality regulator circuit works in a hard switching state, there is a phenomenon of diode reverse recovery, and the switching loss of the converter device is large, which limits the improvement of the operating frequency, resulting in the need to use a larger filter and reducing the circuit efficiency.

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