Study On Electromagnetic And Mechanical Charicteristics Of Permanent Magnet Synchronous Traction Motor For Electric Vehicle Application

Permanent magnet synchronous machines(PMSMs)have been widely used in electric vehicles for the advantages of high torque density,high efficiency and wide costant power range.However the demanding requirements for traction motor as very high operating speed and very compact volume have lead to electrical and mechanical constrains.The noise,vibration and harshness(NVH)problems of vehicles are of great concern.The study of the multi-physic characteristics of PMSMs,including the electromagnetic and structural performance,is investigated in this paper.The target traction machine chosen for this study is the one adopted in Camry 2007.The electromagnetic performance of the target motor,such as inductance characteristics,power factor,loss and efficiency in the whole operation range,is evaluated using finite element analysis method.Analytical models for estimating the air gap flux density and electromagnetic force in interior permanent magnet synchronous machine(IPMSM)with distributed windings are established.The effects of stator slots and rotor saliency are taken into consideration to ensure the validity of the model.Temporal and spatial harmonic distributions of electromagnetic force are studied separately.The electromagnetic force of Camry 2007 is evaluated using 2-D finite element analysis(FEA)and 2-D fast Fourier transformation(FFT)method.The simulation results agree well with that predicted from the analytical model.The stress analysis of Camry 2007 is established.The influence of the electromagnetic force on machine stress has been investigated.In order to optimize traction machine performance,the relationship between the width of magnetic bridge and machine electromagnetic and stress performance in Camry 2007 is studied.At last,the modal analysis of Camry 2007 is conducted.As the major contributors to noise and vibration in PMSMs is the radial electromagnetic force,the electromagnetic noise and vibration characteristics of Camry 2007 is explored.