ZVS DC/DC converter with series half-bridge legs for high voltage application

This paper presents a new DC/DC converter with series half-bridge legs for high voltage application. Two half-bridge legs connected in series and two split capacitors are used in the proposed circuit to limit the voltage stress of each active switch at one-half of input voltage. Thus, active switches with low voltage stress can be used at high DC bus application. In the proposed converter, two circuit modules are operated with an interleaved pulse-width modulation scheme to reduce the input and output ripple currents and to achieve load current sharing. In each circuit module, two resonant tanks are operated with phase-shift one-half of switching cycle such that the frequency of the input current is twice the frequency of the resonant inductor current. Based on the resonant behavior, all MOSFETs are turned on at zero voltage switching with the wide ranges of input voltage and load conditions. The rectifier diodes can be turned off at zero current switching if the switching frequency is less than the series resonant frequency. Thus, the switching losses on power semiconductors are reduced. The proposed converter can be applied for high input voltage applications such as three-phase 380-V utility system. Finally, experiments based on a laboratory prototype with 960-W rated power are provided to demonstrate the performance of proposed converter.