A three phase rectifier-type high frequency link inverter without dc-link filter was proposed to improve the reliability, efficiency and power density of the train auxiliary converter. The rectified output voltage peak was efficiently reduced by using a three-level boost converter, whose voltage gain was further optimized considering loss factors and line voltages during the whole operation period. Subsequently, the input voltage feed-forward compensation control strategy was proposed. In addition, based on the different operation modes of the system adopting a six-pulse-demodulation hybrid modulation strategy, a zero current soft switching method with active clamp was proposed. Further loss analysis of the system was implemented within the whole range of input voltages and loads, and its advantage in efficiency was proved. The correctness of the theory analysis was verified by simulation and experiment results.