Hybrid-PWM-Controlled Current-Fed Bidirectional Series Resonant Converter With Low Current Ripple and Wide Voltage Gain

A hybrid pulse width modulation (PWM) control method for the current-fed bidirectional series resonant dc/dc converter (CF-SR BDC) is proposed in this article. In this proposed hybrid PWM control, the switching frequency is fixed to be the resonant frequency to facilitate the optimized design of magnetic components. In addition, the duty cycles of both high-voltage-side and low-voltage-side switches are also, respectively, regulated for different voltage gains. Based on this method, the CF-SR BDC is characterized by wide voltage gain, low current ripple, and high efficiency, as well as achieving soft switching for all the switches over a wide range of load. The operating principles, control method, and circuit characteristics are expounded specifically. A 160-240-V input and 400-V/1-kW output prototype was built in the laboratory, and the experimental results verify the feasibility of theoretical analysis.