Research On PMSMs Traction System In EMU Train Based On Co-simulation Method

The majority of China’s high-speed railway uses the IM(induction motor)traction system which is maturer.With the increase of railway transportation capacity,the demand for energy consumption is increasing as well.In order to save energy,the efficiency needs to be improved.Thanks to the cost reduction and performance promotion of permanent magnet materials,PMSM(Permanent Magnet Synchronous Motor)traction technology becomes research hotspots.The PMSMs have the advantages of high power density,high efficiency and high power factor and has been successfully applied in high-speed railway.This paper will take some researches on PMSM traction system and its simulation.The FEM(Finite Element Method)model of PMSM is established with commercial software in this paper and the optimization about the parameters of motor will also take place according to the demands such as starting torque,efficiency and power factor.The cross coupling between d-axis and q-axis in IPM has been discussed and its impacts on the d-q model,inductance and torque of motor has been analyzed as well.Meanwhile,a vector control simulation model of PMSM from gird side to motor side has been built,which combines the constant speed control strategy of traction system.This model has also united with the FEM model of PMSM turning to a co-simulation model.Based on the co-simulation model,several analyses take place in this paper as follow:(1)A comparison between inverter supply and sinusoidal supply about the performance of PMSM has been analyzed and offers help to motor design.(2)The passing neutral section working condition has been selected to analyze the model of PMSM traction system.A control method of passing neutral section called Id-keeping control method shows a lot of advantages,especially in the DC link voltage.(3)Considering the preparation method of EMU(Electric Multiple Unit),each power unit will have four sets of PMSM to provide power.The performance of PMSM traction system in EMU train under different coordinated control methods are investigated.The mainly two control methods are compared under different working condition of EMU,which has been using in AM and FEM model.