Zero-Voltage Switching PWM Three-Level Full-Bridge DC–DC Converter With Wide ZVS Load Range

This paper proposes a new zero-voltage switching (ZVS) pulse width modulation (PWM) three-level (TL) full-bridge (FB) dc-dc converter, which is composed of a TL FB converter and a TL half-bridge (HB) converter. It is well suited for high input voltage and high-power applications. The proposed topology has the following attractive features: off-state voltage on all switches in the circuit is only half of the input voltage; full input voltage is utilized on the load for the whole operating range; TL output waveform is achieved, which significantly reduces the requirements for the input and output filters; simple switching scheme can be used to control the output voltage in wide range. The converter can achieve ZVS for all power switches in wide load range and even at light load condition; furthermore, less conduction loss is added to achieve soft switching. The operation and important analysis of the proposed converter are given. Experiments are carried out to validate the proposed converter, and efficiency curves are tested and given.