Research Of 4-arms Phase-shift Series Resonant DC/DC Converter

With a wider application of high-voltage DC power supply, the research of phase-shifted full-bridge converter with high-voltage output is more and more important. This paper just based on this.There is output filter inductor in phase-shifted full-bridge converter, the presence of this inductor, not only led to the problem of duty-loss, but seriously, it increases the voltage stress of the high-frequency high-voltage transformer, this is not conducive to the design and realization of the transformer, so the traditional phase-shifted full-bridge circuit is not suitable for high-voltage output occasions. High voltage DC power supply always only use capacitor as filter, it is the way that phase-shifted series resonant converter takes. Because of no output filter inductor, the converter is not only applicable to high-voltage output, but also solved the problem of duty-loss. However, it is also because there is no output filter inductor to hold the circuit of the load, the rang of the load for ZVS is very narrow, which significantly limits its application.So as to solve this problem, this paper proposed a new topology. By adding a pair of auxiliary arms, the four-arm phase-shifted series resonant converter is constituted. When the load circuit is not enough, the auxiliary arms provide current to make sure the main bridge is ZVS, and so as the auxiliary arms.Due to the involvement of auxiliary current, the conditions for main bridge to achieve ZVS are no longer limited by the load, it can be always ZVS. This greatly expanded the application of the converter. In principle, the auxiliary current can be regulated according to the needs, big auxiliary current is provided when load is light, small when load is height. And also the regulation for advanced-arm and lag-arm is independent. This regulating way can optimize the circuit, reduce the loss and improve the efficiency.In this paper, the functions of the four-arm phase-shifted series resonant converter are analyzed and resolved, and also be proved in simulation and experiment.