Research on a Novel Soft-Switching Buck Converter Based on Energy Feedforward

In the traditional ZVT soft-switching DC-DC converters, the resonant energy transmission path is complicated and the auxiliary switches may operate in hard switching. This paper proposes an energy-feedforward ZVT soft-switching Buck converter, all the switches keep soft-switching operation, and the resonant energy is transmitted directly to the load through the forward transformer instead of returning to the source or indirectly flowing to load, which is conducive to improve the conversion efficiency. After theoretical analysis, the design process of key parameters is given, and verified through simulation. Finally, an experimental prototype is constructed with 200W output, 200kHz operating frequency. The experimental results show that soft-switching operation of all switches is maintained in load range from 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">%</sup> to rated power. Compared with the traditional hard-switching Buck, the voltage and current spike of the main switch are reduced largely, the efficiency is better in the whole test range, improved from 94.54% to 97.34% at full load.