A Novel Soft Switching Bidirectional DC–DC Converter Using Magnetic and Capacitive Hybrid Power Transfer

This paper proposes a new bidirectional dc-dc converter capable of improving the convenience and modularity of the dc power grid system. By the unique operation of the $LC$ resonant transformer, the proposed converter achieves bidirectional power control with only two switches. Also, the resonant transformer drives the soft switching turn-on and turn-off over a wide power range. Hence, the circuit has high potential to downsize the converter by exploiting high frequency and simplicity. This paper provides the operating principle and the experimental verification of the proposed circuit. A prototype was fabricated by using a simple and high-density printed circuit board ($\geq$ 10 W/cc). It is verified that the circuit resonant operation successfully drives bidirectional power control with high efficiency ($\geq$92%). An application example is also provided for dc grid system integration.