Three-phase four-wire system zero voltage switching back-to-back converter circuit and modulation method thereof

Abstract

The invention discloses a three-phase four-wire system zero voltage switching back-to-back converter circuit and a modulation method thereof. The circuit comprises converter circuit inverter side loads, filter capacitors, filter inductors, rectifier side filter inductors, six sets of bridge arms formed by two full control main switches equipped with anti-parallel diodes, a resonance branch formedby an auxiliary switch including the anti-parallel diode and connecting between the DC bus capacitor and the six sets of bridge arms, a clamping capacitor and a resonance inductor, and resonance capacitors connected in parallel on the two ends of the main switch and the auxiliary switch. The pulse signals of the auxiliary switch and the main switch are synchronized so that zero voltage switching of all the switches can be realized in each switching period, the reverse recovery current of the main switch anti-parallel diodes can be effectively suppressed, the switching loss is low, the circuitefficiency is high, the switching frequency can be enhanced and the system power density can be enhanced.

Description

technical field [0001] The invention relates to the technical field of converters, in particular to a three-phase four-wire zero-voltage switch back-to-back converter circuit and a modulation method thereof. Background technique [0002] The traditional two-level three-phase four-wire back-to-back PWM converter includes twelve fully-controlled main switches (S i1 ~S i6 and S o1 ~S o6 ) composed of a three-phase bridge arm, three input filter inductors (L ai , L bi , L ci ), connect two DC bus capacitors (C dcp , C dcn ), connect three output filter inductors between the output midpoint of the output bridge arm and the load (L ao , L bo , L co ), the neutral points of the positive and negative bus capacitors, the neutral point of the power grid, and the neutral point of the load are connected together. The circuit works in a hard switching state, there is a diode reverse recovery phenomenon, and the switching loss of the converter device is large, which limits the ...

AI Technical Summary

Problems solved by technology

The circuit works in a hard switching state, there is a diode reverse recovery phenomenon, 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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