Research On Wide Input Active Clamp Phase-shift Full-bridge ZVS Converter

In recent years, with the wide application of power electrnic devices, DC/DC converters with wide input voltage range and high efficiency are more and more needed. In power systems, the DC/DC converter is closely related to the performance, efficiency, size, weigh, and cost. So going on the research of DC/DC converter with wide input voltage is very important. Based on one space power project, The research is mainly focused on isolated DC/DC converters with high efficiency and wide input voltage.The active clamp phase-shifted full-bridge ZVS converter is finally selected as main topology. As wide input voltage causes the problems of voltage oscilcation and peak across rectifiers, two clamping diodes are introduced to the primary side of the transformer, the active-clamp snubber circuit is introduced to the second side. Working principle and operating characteristics are analyzed. In order to improve the conversion efficiency, converter loss has been analyzed and calculated in detail. Three ways are adopted: synchronous rectifier technology, toroidal transformer with low core loss, SIC diode instead of SI diode. Establish the small-signal model and design the closed-loop compensation network, simulation results of MATLAB show that the compensation parameters can make the converter stable.Based on the theoretical analysis and calculation of the parame ters, simulation of phase-shifted full-bridge converter and active clamp phase-shifted full-bridge ZVS converter are established. The simulation results show that the proposed method can reduce voltage oscilcation and peak. An experimental prototype is built. The voltage and current waveforms and efficiency are tested. experimental tests show that in the wide input voltage range, active clamp phase-shifted full-bridge ZVS converter is more efficient and better performed. Finally, in order to expand the input voltage range, the further research and simulations are carried on. The simulation results prove the correctness of the two stage structure.