Analysis and implementation of passive soft switching snubber for PWM inverters

To realize a three-phase soft-switching inverter with a simple structure, low cost, and easy modularization, this paper proposes a novel three-phase passive soft-switching inverter, which realizes soft-switching of the switches in the inverter through energy consumption of the auxiliary snubber circuit. When compared with the traditional passive soft-switching inverter, it avoids the use of transformers, coupled inductors, and bulk electrolyte capacitors. Thus, it has a small size, a high power density, and is suitable for integration. Its three single phases are independent of each other, which makes it easy for the inverter to apply various control strategies. This study chooses a single-phase circuit, and investigates the operating principle, soft-switching implementation characteristics, and parameter design methods of the novel passive soft-switching inverter under various operation modes. Finally, a 10 kW/16 kHz prototype is made using an IGBT as a switch, and experiments are conducted to confirm the validity of the inverter.