A ZVS modulation method for a three-phase four-wire ZVS inverter

Abstract

The invention discloses a zero-voltage switch modulation method of a three-phase four-wire system zero-voltage switch inverter. The modulation method compares the three-phase main switch modulation wave of the three-phase four-wire zero-voltage switching inverter with the sawtooth carrier, and then generates the main switch signal through the inverter and the rising edge delay module, and converts the three-phase four-wire zero-voltage switching The auxiliary switch modulation wave of the voltage switch inverter is compared with the sawtooth carrier, and then the bridge arm through signal and the auxiliary switch signal are generated by the rising edge delay module, the inverter and the falling edge delay module. In the three-phase four-wire zero voltage switch During the commutation period of the fully-controlled main switch of the inverter, the through signal is applied to the fully-controlled main switch to provide a freewheeling circuit for the magnetization of the resonant inductor to store sufficient resonance energy. The invention has a simple structure, can realize full-range soft switching in the power frequency cycle, realizes zero-voltage turn-on of all switching devices, has small switching loss, high circuit efficiency, can suppress reverse recovery of diodes, and reduces 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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