Analysis and Design of a Low-Complexity ZVS Buck-Boost Converter

A circuit structure and operating method for achieving a soft-switching operation of a non-inverting buck-boost converter is proposed. The converter is derived from the two-switch buck-boost converter. It achieves ZVS by replacing a diode with an active switch, driven with a gate signal complementary to the main transistors’ control signals. In this way, the inductor current can be clamped and used to achieve soft-switching transitions of all transistors in the converter. The circuit achieves ZVS by design, and the ZVS range can be adjusted by adding a capacitor parallel to a diode or switch. The converter does not need a complex control or sensor circuit for proper operation. The operating principle and converter design are described in detail. The proposed converter operation is verified using simulations and experimental results.