Efficient single-phase full bridge soft-switching inverter

For the sake of high-efficiency of the inverter, a single-phase full bridge inverter is proposed. In each switching period, only one main switch and one auxiliary switch needs switch. The duration of conduction state of the auxiliary switch is constant and independent of the instantaneous value of load current. During the workflow in each switching period, the voltage across the main switch decreased to zero before the main switch was turned on. The main switch achieved zero-loss turn-on. In the workflow of one switching period, parameter design rules and theoretical loss of auxiliary circuit were discussed. In addition, the calculation of specific experimental parameters was implemented. The working principle and parameter design process of the circuit were analyzed in detail, and a 2 kW prototype was built. The experimental waveforms derived from a 2 kW prototype showed that the switches work in the state of soft-switching; the total harmonic distortion rate of output current waveform has advantages, and the output current waveform at low frequency does not have obvious distortion. The efficiency of the inverter at rated power is up to 98.4%. The experimental results prove that the inverter can work efficiently and stably at low output frequency by reducing the switching loss. © 2020, Harbin University of Science and Technology Publication. All right reserved.