Instantaneous Reactive Power Reduction of Ripple-Free Resonant Buck Converter Using Bidirectional Switch

Abstract

This paper presents an instantaneous reactive power reduction method for rippleless resonant bidirectional converter in backward operation. The method is applied to improve an existing converter topology that features high step-up/down capability, high efficiency and zero input ripple. The original topology suffers from significant reverse current when transferring power backwards under synchronous rectification. 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 circulating 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. A 600-W converter prototype has been implemented to show the performance of the converter.