Research On The High-Frequency Output Soft-Switching Inverter

With the development of Power Electronic, AC sources of high power and high frequency have been widely used, especially in AC Distributed Power Systems. And high frequency AC bus is more and more attractive. Based on comparison of different DC/AC inverters and resonant filters, an output high-frequency sine-waveform inverter is adopted, which is composed of Phase-shifted controlled ZVS full bridge inverter and series-parallel resonant filter. With the consideration of the high power, it is implemented with input-series and output-parallel mode of several modules.Phase-shifted controlled ZVS full bridge inverter can realize ZVS for the power switches with the resonance of the leakage inductor of the transformer and the intrinsic capacitors of the power switches. So it is used widely in medium and high power applications. The operation principles of high frequency output phase-shifted controlled ZVS full bridge inverter and the realization condition of the soft switching are analyzed in detail in this dissertation. In order to achieve ZVS of all switches, series-parallel resonant filters must be designed to be inductive. Three approaches of the inductive series-parallel resonant filters are discussed. The influences of three approaches on THD of output voltage, the condition of ZVS achievement, the characteristic of the output voltage and the current value of series resonant loop are respectively discussed. And each design procedure is given in detail. With different positions of series-parallel resonant filter and transformer, the effect on performance of series-parallel resonant filter are compared.A 10kW prototype of high frequency output phase-shifted controlled ZVS full bridge inverter is built. The design procedures of the main circuit and control circuit are presented. The simulation and experimental results verify the validity of the above principle analysis and design.