新型高效率并联谐振直流环节软开关逆变器

Novel High Efficiency Parallel Resonant DC Link Soft-Switching Inverter

为降低传统硬开关逆变器的开关损耗,提出了一种新型高效率并联谐振直流环节软开关逆变器。通过在传统硬开关逆变器的直流环节添加辅助谐振单元,使直流母线电压周期性地归零,可以实现逆变桥主开关器件的零电压开关,而且辅助开关器件也可以实现零电压开关和零电流开关。此外,辅助谐振单元中的器件都位于直流母线的并联支路上,有利于降低辅助谐振单元的损耗,从而实现逆变器效率的明显改善。对其工作原理进行分析,给出不同工作模式下的等效电路图,软开关的实现条件和控制策略。制作一个5kW的实验样机,通过实验结果验证该软开关逆变器的有效性。

A novel high efficiency parallel resonant DC link soft-switching inverter is proposed to reduce switching loss in the conventional hard-switching inverter in this paper.Auxiliary resonant unit was added to DC link of conventional inverter to make DC-bus voltage decrease to zero periodically,which realizes zero-voltage operation of all switching devices in inverter.Switching devices in the auxiliary resonant unit con also be operated under zero-voltage switching and zero-current switching.In addition,devices in the auxiliary resonant unit are in parallel with DC-bus to reduce loss of auxiliary resonant unit.Therefore,efficiency can be improved obviously.The operation principle was analyzed.The equivalent circuits at different operation modes,conditions for realization of soft-switching,and control strategy are presented.A 5kW laboratory prototype is built.Experimental results are proposed to confirm validity of soft-switching inverter presented.