Zero voltage switch modulation method of three-phase four-wire system zero voltage switch inverter

Abstract

The invention discloses a zero voltage switch modulation method of a three-phase four-wire system zero voltage switch inverter. The zero voltage switch modulation method of a three-phase four-wire system zero voltage switch inverter includes the steps: comparing a three phase main switch modulated wave of a three-phase four-wire system zero voltage switch inverter with a sawtooth carrier wave; generating a main switch signal through an inverter and a rising edge time-delay module; comparing an auxiliary switch modulated wave of the three-phase four-wire system zero voltage switch inverter with the sawtooth carrier wave; generating a leg straight-through signal and an auxiliary switch signal through the rising edge time-delay module, the inverter and a falling edge time-delay module; and applying the effect of the straight-through signal to a full control main switch during the commutation process of the full control main switch of the three-phase four-wire system zero voltage switch inverter to supply a freewheeling loop for magnetizing of a resonant inductor so as to store enough resonant energy. The zero voltage switch modulation method of a three-phase four-wire system zero voltage switch inverter is simple in structure, and can realize full range soft switching in the power frequency period. Besides, all the switching devices can realize zero voltage switching so that the zero voltage switch modulation method of a three-phase four-wire system zero voltage switch inverter has low switching loss and high circuit efficiency, and can restrict reverse recovery of a diode and reduce electromagnetic interference.

Description

technical field [0001] The invention relates to a three-phase inverter and its modulation method, in particular to a zero-voltage switching modulation method for a three-phase four-wire zero-voltage switching inverter. Background technique [0002] The inverter is a device that converts direct current into alternating current. A common topology such as a three-phase four-wire inverter consists of six fully-controlled main switches (S a1 ,S a2 ,S b1 ,S b2 ,S c1 ,S c2 ) composed of three-phase bridge arms, which are respectively connected to the output midpoint (A, B, C) of each phase bridge arm and the load (R a , R b , R c ) between the output inductance (L a , L b , L c ), the output capacitor connected across the load (C a0 ,C b0 ,C c0 ), two DC bus capacitors (C dc1 ,C dc2 ), connected to the midpoint of the positive and negative bus capacitors (0), the midpoint of the output capacitor and the midpoint of the load. The circuit works in a hard switching sta...

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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 for a larger filter, which reduces the circuit efficiency and has electromagnetic interference.

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