中文摘要：

为提高逆变器的效率，提出了一种新型并联谐振直流软开关逆变器的拓扑结构，在辅助谐振电路中设置了1对反并联的晶闸管来控制谐振电流，使逆变器的直流环节电压周期性下降到零，逆变器的主开关可以在零电压条件下完成切换，同时辅助开关器件在逆变器换流过程中也实现了零电压开关或零电流开关。该逆变器在换流过程中不需要设定和负载有关的电感电流阈值，有利于降低辅助电路损耗和简化控制。对电路在1个开关周期内的各个工作模式进行了理论分析，给出了设计规则，并建立起辅助谐振电路损耗和分压电容的电压偏差量的数学模型。制作了一台5 kW的实验样机，实验结果表明逆变器的工作过程符合原理分析，所以该软开关逆变器可以有效地提高效率。

英文摘要：

A novel parallel resonant DC link soft-switching inverter was proposed to improve the efficiency of inverter. A pair of anti-parallel thyristor in the auxiliary resonant circuit was used to control resonant current so that DC link voltage of the inverter decreased to zero periodically. Zero-voltage operation of all main switching devices in inverter was realized. Auxiliary switches were also operated under zero voltage switching or zero current switching in the commutation process. Inductor current threshold relative to load was not set in the commutation process, which was beneficial to reduce the loss of auxiliary circuit and simplify control strategy. Every operation mode in a switching period was analyzed in theory. The design rule was also given. Furthermore, the mathematical models for auxiliary resonant circuit loss and voltage deviation of voltage dividing capacitors were established. A 5 kW laboratory prototype was built. Experi-mental results demonstrate that working process of the inverter accord with principle analysis. Therefore, the proposed soft-switching inverter can effectively improve efficiency.