零电压开关三电平Buck-Boost双向变换器

摘要

针对非隔离型三电平Buck-Boost双向变换器,提出一种零电压开通(ZVS)实现方案.该方案在不添加任何辅助元件的情况下,可使非隔离型三电平Buck-Boost变换器的所有开关管在全负载范围内实现ZVS,提高变换器的效率.此外,利用异相控制、电感电流倍频降低电感的体积,提高功率密度.首先对实现ZVS的工作过程进行分析,并且分析反向电流IR对软开关的影响;然后推导出死区时间和开关频率表达式;最后搭建实验样机,通过Buck模式和Boost模式的实验来验证该方案的正确性和有效性.%Acontrol scheme of achieving zero-voltage-switching (ZVS) for the non-isolated three-level Buck-Boost bidirectional converter is proposed is the paper. All switches can achieve ZVS in the whole load range without additional circuitry, thereby improving the power conversion efficiency. Furthermore, this scheme utilizes an out-phase control, which can double the inductor current frequency, decrease the inductor volume greatly and improve power density. Firstly, the operation principle of ZVS is analyzed. Secondly, the influence of the reverse currentIR on soft-switching during the dead-time interval is explained. Then, the expressions of dead-time and switching frequency are derived. Finally, an experiment prototype is built and tested in both Buck mode and Boost mode to verify the correctness and effectiveness of the proposed scheme.