Design And Research On Railway Passenger Train Charger With Digital Control

The power supply technology of railway passenger train is the basic guarantee for safely and comfortable operation.After continuous development,the locomotive power supply of DC600V voltage grade has become the main power supply mode of railway passenger train in China.DC600V/DC110V charger of the train mainly used for charging the battery on the train,but also for the lighting,control system and other DC110V device,it is an indispensable power supply device for modern passenger train,the performance of the charger directly determines the ride comfort and running stability of the train.Therefore,the research on the train charger is of great significance to the development of the electrification of the train.The paper according to the parameters of the charger,a digital control type charger is designed.Firstly,this paper according to the design requirements of the charger,the topology of the charger is selected,and the working principle of the topolopy is introduced.As the power of the charger is larger,and in order to achieve high conversion efficiency,this paper chooses the phase-shifted full-bridge soft-switching converter as the main circuit topology.Among them,the secondary rectifier topology is selected by the full-wave rectifier circuit,and the DC-DC transform topology adopts the lagging bridge arm series diode phase-shifted full-bridge ZVZCS converter.Secondly,according to the parameters of the charger,the main circuit components were calculated and selected,and the hardware circuit of signal sampling,isolation drive,hardware protection and auxiliary power module in control system of the charger were designed and described.Thirdly,the paper is based on the concept of effective duty cycle,a small-signal model of phase-shifted full-bridge ZVZCS converter is established on the small-signal model of Buck converter,and the related transfer function is deduced.As the charger needs to work in constant voltage output and current limiting charge mode of operation,this paper uses two kinds of output single closed-loop control strategy,and the PI regulator parameters of these two modes are designed by using SISOTOOL in the MATLAB.The component parameters of the main circuit and the stability of the two closed-loop control mode are verified by the closed-loop simulation model built in the PSIM,and the correctness of the design scheme is preliminary proof.Finally,this paper chooses TMS320F28335 chip to realize the digital control system of the charger.The realization scheme of the charger software system is given,and the physical test is carried out on the assembled charger prototype.The test results show that the charger designed in this paper can realize the soft switch of ZVZCS,and the efficiency can reach 93%under rated load,the closed-loop regulation performance of the two control modes of charger can meet the requirements.