变压器辅助换流的谐振极型软开关逆变器

摘要

A resonant pole soft-switching inverter with transformer-assisted commutation was proposed to realize efficiency in the inverter .A transformer was used to assist commutation in the circuit and it avoided the bulk capacitors which divided the voltage in the DC side and there was no center tap potential varia -tion problem.It could realize zero current switching operation of auxiliary switching devices and zero volt-age switching operation of main switching devices .The voltage across devices was no more than DC power voltages.The operation principle and realization conditions of the soft-switching inverter were analyzed in detail on the basis of equivalent circuits at different operation modes in one PWM cycle .The mathematical model for auxiliary resonant circuit loss was established and the influence of resonant parameters on the loss of auxiliary circuit was discussed .A 4 kW laboratory prototype was built .Experimental results show that auxiliary switching devices and main switching devices are operated under soft -switching .The reso-nant pole inverter presented can effectively improve efficiency and reduce switching loss .%为提高逆变器的运行效率,提出了一种变压器辅助换流的谐振极型软开关逆变电路拓扑结构.该拓扑结构用高频变压器来辅助换流,没有设置串联在直流母线间的均压电容,解决了中性点电位变化问题.该逆变器的主开关和辅助开关均能完成软开关动作,并且所承受的电压都不高于直流电源电压.给出了一个开关周期内逆变器在不同工作模式下的等效电路图,详细阐述了该逆变器的工作过程,给出了软开关实现条件,并建立起了辅助电路损耗的数学模型,讨论了谐振参数对辅助电路损耗的影响.最后制作了一台4 kW的单相实验样机,实验结果表明逆变器中的开关器件都工作在软开关条件下.该有源谐振极型软开关逆变器可以有效提高效率,减小开关损耗.