Capacitor Voltage Self-balancing DC/DC Converter for EMU High-frequency Auxiliary Power Supply
High-frequency auxiliary power supply(HFAPS)has the advantages of high power density and high conver-sion efficiency,which is an important way to save train space,optimize train environment,and reduce power consump-tion.This paper proposed a DC/DC converter that contains a voltage self-balancing resonant converter(VSBRC)and an isolated DC/DC converter.The proposed topology can achieve reduction and equalization of the input DC voltage by u-sing VSBRC,which can help reduce the switch voltage stress and the number of rear-stage isolated DC/DC converters.Meanwhile,all the switches in VSBRC can achieve zero-current switching to reduce the switching losses of the convert-ers.In addition,VSBRC causes the voltage of the input serial capacitors to balance automatically without the need to use additional voltage balancing control strategy.Compared with the existing HFAPS,the proposed topology can reduce the number of switches and transformers,improve efficiency and reduce control complexity.In this paper,with the analysis of the working principle,control method,and voltage self-balancing characteristics,the corresponding parameter design method was put forward.Finally,a 6 kW prototype was built to verify the feasibility of the proposed topology by conduc-ting voltage balance,dynamic switching,and soft-switching experiment.
high-frequency auxiliary power supplycapacitor voltage self-balancing converterzero-current switchingcontrol strategyparameter design
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