中文摘要：

为提高逆变器的变换效率，提出了一种具有并联谐振直流环节的新型软开关电压源逆变器的拓扑结构。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，实现逆变桥开关器件在零电压条件下完成切换，而且辅助开关器件也可以实现零电压开关或零电流开关。此外，电路中避免了使用大电容，没有中性点电位的变化问题。文中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。制作一个5kW的实验样机，实验结果表明该并联谐振直流环节软开关逆变器的主开关实现了零电压开关，在额定输出功率下，相比于硬开关逆变器，效率提高了3％。

英文摘要：

This paper proposes a novel soft-switching voltage source inverter with parallel resonant DC link to improve effi-ciency of inverter .We added auxiliary resonant unit to DC link of conventional inverter to make DC-bus voltage decreased to zero periodically ,which realized zero-voltage operation of all switching devices in inverter .Furthermore ,we also operated auxiliary switches under zero voltage switching or zero current switching .In addition ,we avoided the bulk capacitor in the circuit and there was no center tap potential variation problem .We analyzed the operation principle and presented the equivalent circuits at different operation modes .We had built a 5kW laboratory prototype .Experimental results show that we can operate main switching devices under zero voltage and enhance the efficiency by 3% under rating power ,compared with hard-switching inverter .