Design And Analysis Of Fractional Slot Concentrated Winding PMSM For Electric Vehicles

Permanent magnet synchronous motor（PMSM）is widely used as traction motor due to its merits including high power density and high efficiency.Fractional slot concentrated winding permanent magnet synchronous motor has attracted many researchers due to its merits such as short end winding length and simple manufacture process.According to the design requirements of electric vehicle motors,a fractional slot concentrated winding permanent magnet motor is designed.Firstly,the related theory of fractional slot concentrated winding motor is expounded in the thesis.The single layer and double layer structure of fractional slot concentrated winding motor are compared and the winding factors of magnetic motive force（MMF）harmonics are derived.Secondly,the MMF harmonics of fractional slot concentrated winding and integral slot distributed winding are compared.Comparing the armature reaction field and demagnetization ratio distribution in permanent magnets,it is found that under the same input current and serial turns per phase,MMF harmonics of fractional slot concentrated winding motors cause higher demagnetization field.Finally,according to the design requirements and targets of the permanent magnet synchronous motor,the stator and rotor structure of the motor are designed.The peak torque,cogging torque and no-load back EMF of the motor are analyzed by finite element method.The eddy current loss and cogging torque of the permanent magnet are reduced by segmenting the permanent magnet and optimizing the magnetic circuit of the stator and rotor.Aiming at the high-speed and high-temperature operation condition,the mechanical stress and demagnetization of the permanent magnet are verified to ensure the reliability of the motor.