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为提高逆变器转换效率,提出了一种主开关承受电压不高于直流电源电压的无辅助开关的谐振极逆变器.与硬开关逆变器相比,该软开关逆变器通过增加由少量无源器件组成的谐振电路,能使开关器件在开通瞬间完成零电流开通,在关断瞬间完成零电压关断.此外,该谐振极逆变器在死区时间内输出相电流可通过辅助电路续流,有利于减小低输出频率下的相电流畸变率.依据不同工作模式下的等效电路图,分析工作原理,说明了软开关实现条件,完成了辅助电路功耗的理论分析,并给出了参数设计过程.制作一台10kW的三相实验样机,实验结果表明逆变器的开关器件实现了软开关,而且输出相电流在低频下无畸变.因此,该软开关逆变器具有开关损耗低和输出电流畸变率低的优点.“,”A resonant-pole inverter,in which the main switching voltage was no more than the supply voltage and no auxiliary switch was taken out,was proposed to improve conversion efficiency of the inverter.Compared with the hard-switching inverter,the inverter could make switching devices achieve zero-current turning on at the moment of turning on and zero-voltage turning off at the moment of turning on via adding resonant circuits composed of few passive devices.In addition,freewheeling of output phase currents of the inverter could be realized via auxiliary circuits in the dead-time,which was beneficial to the reduction of the distortion ratio of the output phase current in low output frequency.The operation principle was analyzed in detail on the basis of equivalent circuits at different operation modes.The conditions for realization of soft-switching were presented.The theoretical analysis of auxiliary circuit losses was made and the design process of resonant parameters was given.A 10kW three-phase laboratory prototype had been built.Experimental results showed that switching device of the inverter could realize soft-switching and output phase currents had no distortion in low output frequency.Therefore,the proposed soft-switching inverter has the advantage of low switching losses and low distortion of output currents.