Reverse Current Elimination for Capacitor Voltage Balanced Bidirectional Resonant Converter Using a Bidirectional Switch

In this paper, we present an instantaneous reverse current elimination method for a capacitor voltage balanced bidirectional resonant converter operating in the backward operation. A conventional high step-up resonant converter with balanced capacitor voltage may suffer from a significant reverse current due to a large fluctuation of the resonant capacitor voltage in the backward operation. By adding a single bidirectional switch in the circuit, we are able to block the reverse current in the backward operation, which dramatically reduces the reverse current and current stress on the switch. A non-complementary modulation strategy for the bidirectional switch is developed to further reduce the conduction loss, which comes from the use of the bidirectional switch. As a result, the proposed bidirectional converter has high step-up/down capability, high efficiency, and balanced capacitor voltage. A 400-W converter prototype has been implemented to show the performance of the converter.