DOUBLE-AUXILIARY-RESONANT-POLE TYPE THREE-PHASE SOFT SWITCHING INVERTER CIRCUIT AND MODULATION METHOD THEREFOR

摘要

A double-auxiliary-resonant-pole type three-phase soft switching inverter circuit and a modulation method therefor. The circuit comprises three-phase main inverter circuits and three-phase double-auxiliary-resonant commutation circuits, wherein the phase-A double-auxiliary-resonant commutation circuit (1), the phase-A main inverter circuit (2), the phase-B double-auxiliary-resonant commutation circuit (3), the phase-B main inverter circuit (4), the phase-C double-auxiliary-resonant commutation circuit (5) and the phase-C main inverter circuit (6) are sequentially connected in parallel and are connected to a DC power source (E) in parallel, and all main switching tubes work according to the modes of sine pulse width modulation and complementary switch-on with a phase difference being 180 degrees. By means of the circuit and the modulation method therefor, separation of resonance current of the double-auxiliary-resonant commutation circuits and load current at the current commutation time can be achieved, current stress of auxiliary switching tubes is effectively lowered, and by avoiding superposition of load current and resonance current at the current commutation time, loop current loss of the double-auxiliary-resonant commutation circuits can be effectively lowered, and especially the efficiency can be greatly improved under the light load condition.