A resonant inverter and its soft switching boundary conditions analysis

This paper presents a high efficiency, low voltage stress and easy to be controlled PWM soft switching three phase inverter, which using relatively small inductor and capacitor to charge and discharge the parallel capacitors of the main switches and realize the ZVS on operation, a bidirectional switch unit is used to realize the quasi-resonant and reduce the resonant losses. Both switching on and off of auxiliary switches are zero current switching. The soft-switching conditions are analyzed by state plane method and the soft-switching boundary conditions are derived. Adjusting the operation time of each working period can easily control the initial values of state variables, thus satisfy the soft switching conditions of inverter. Simulation and experimental results are proposed to verify the theoretical analysis.