Research On New Technology Of Traction System For Metro Vehicles

With the acceleration of domestic urbanization and changes of travel mode,the demand for urban transportation is increasing day by day.The subway has become the first choice for urban transportation due to its advantages of large passenger capacity and convenience.The paper does the research based on National Science and Technology Support Project of "Next Generation Metro Vehicle Technology Research and Demonstration Application".The paper carries out the research on the new technology of the subway train traction system.To be specific,the paper does the research on the control strategy of permanent magnet motor,the self-traction strategy and the energy allocation strategy of power battery in subway system.Aimed at the control strategy of permanent magnet motor of subway train,the paper carries out the research on structure of permanent magnet motor and its dynamic mathematical model in two-phase rotating coordinate system.On this basis,several common vector control methods are compared and analyzed.In this paper,the control method of the maximum torque-current ratio is used as the control method of the PM synchronous motor and the paper carries out the research on the mathematical solution of the current vector trajectory and the engineering implementation method.The protection control strategy of PM motor traction system is studied to ensure the safe operation of the trains.At last,the control strategy was verified through the experiment.For the self-traction control strategy of subway trains,this paper firstly introduces the function of the self-traction of subway trains,and its composition is analyzed as well.Then,the current topology of the self-traction system of the vehicles is studied.Based on the optimization design of power supply by using high-voltage power batteries,the strategy of self-traction topology with the power supply by power batteries is obtained,and the control logic of its implementation is discussed.As to the energy allocation strategy of power batteries of metro trains,the energy demand of metro trains is analyzed according to its different operating conditions firstly,and proper power batteries of vehicles are selected.Then,a suitable on-board DC/DC converter topology is designed,and the rule-based energy management strategy,namely the logical threshold management strategy is designed for the energy management system of metro trains.Finally,its function is proved by some simulation results.