Design and control of a bi-directional resonant DC-DC converter for automotive engine/battery hybrid power generators

In this paper a bidirectional DC-DC converter is proposed for automotive engine/battery hybrid power generators. The two-stage bidirectional converter employing a fixed-frequency series loaded resonant converter(SRC) is designed to be capable of operating under zero-current-switching(ZCS) turn on and turn off regardless of voltage and load variation, and hence its magnetic components and EMI filters can be optimized. Also, a new autonomous and seamless bidirectional voltage control method that combines two individual controllers for low voltage side control and high voltage side control by introducing a variable current limiter is proposed to provide uninterrupted power to critical AC loads and reduce the size of the DC bus capacitor. Experimental results from a 5 kW prototype are provided to validate the proposed concept.