Smooth Reversal of Power Transfer Direction for ZVS Bidirectional Four-Switch Buck-Boost Converter

Bidirectional dc-dc converters have found wide applications in renewable energy generation systems, residential energy storage systems, and electric vehicles. The four-switch buck-boost (FSBB) converter features low voltage stress on power switches, positive output, and bidirectional power transfer. In this article, the combined pulse width modulation (PWM) and phase-shift control is adopted for the FSBB converter to realize zero-voltage-switching (ZVS) for all the power switches in both forward and reverse power transfer operation. Then, the control methods for achieving smooth reversal of power transfer within one switching cycle are proposed, avoiding excessive current overshoot. Finally, a prototype of the bidirectional FSBB converter with an output power ranging from −5 to 5 kW is built and tested in the lab, and the experimental results are provided to verify the effectiveness of the control methods.