Switching Transition Analysis in a Subresonant Half-Bridge Series Resonant Converter for High Power and High Switching Frequency Applications

In this paper a comprehensive analysis of the switching transitions of the Half-Bridge Series Resonant Converter (HB-SRC) for high power and high switching frequency applications is presented. With the goal of minimizing converter losses as well as reducing current and voltage oscillations during the switching transitions, optimal time instances for turn-on and turn-off signals of the power switches for the non-synchronous control are calculated. Comprehensive simulative investigation has been carried out to verify the feasibility of this control method. Semiconductor loss distribution is explained in detail and optimal switching transition with regards to semiconductor losses and control robustness are identified. A hardware prototype of a HB-SRC combining an output power of 250 kW and a switching frequency of 50 kHz has been developed and is used for the validation of simulation results. Finally, the robustness of the control is demonstrated experimentally for a wide range of operating power.