Analysis And Design Of 18slot/10pole Six Phase Direct Drive Fault-tolerant Permanent Magnet Synchronous Motor For Electric Vehicle

Since the birth of the internal combustion engine vehicle more than 100 years,it has had a profound impact on modern transportation,economy and life.However,with the improvement of environmental protection awareness and the worry about the energy crisis in various countries around the world,the fuel vehicle will soon withdraw from the historical stage in the near future.The electric vehicle with the advantages of low energy consumption,low noise and no pollution is recognized as the development trend of the future automobile.The motor technology is related to the power and safety of the automobile,which is a particularly important technology in the related technologies of electric vehicle.Multi-phase fault-tolerant permanent magnet synchronous motor improves the fault-tolerant performance of the motor system,which provides the possibility for the operation under the fault condition.After analyzing the development trend and research status of drive motor and multi-phase fault-tolerant motor of electric vehicle,this paper gives and analyses the related models of multi-phase motor,which lay a foundation for further design optimization of motor.When analyzing the winding theory of fault-tolerant motor,the single-layer fractional slot concentrated winding and double-layer fractional slot concentrated winding are simulated and compared by using finite element analysis,and the reason why single-layer fractional slot concentrated winding is used for multi-phase motor is pointed out.The performance of fault-tolerant permanent magnet synchronous motors with surface mounted rotor and V-type rotor under rated operation and four different fault conditions is investigated by finite element analysis.The electromagnetic performance,loss and temperature,and fault-tolerant performance are compared and analyzed in detail.The motor with surface mounted rotor has more advantages in electromagnetic performance,the motor with V-type rotor has more advantages in loss and temperature.In terms of fault-tolerant performance,the torque lost in the fault condition of the motor with surface mounted rotor is less,the vehicle can retain more power,and the fault-tolerant ability is stronger.However,its self-inductance is lower than that of V-type rotor motor,and the proportion of phase to phase mutual inductance is higher,resulting in the phase to phase isolation performance is lower than that of V-type rotor motor.Furthermore,in order to improve the fault-tolerance performance of the motor with surface mounted rotor and reduce the proportion of phase to phase mutual-inductance,this paper studies three different stator winding arrangement schemes of multi-phase motor,and points out that the sector centralized fractional slot concentrated winding stator topology can effectively reduce the phase to phase mutual inductance.After that,the improved unequal teeth width topology is put forward,and the torque density of the new topology is further improved.The available pole-slot combination scheme of the sector centralized fractional slot concentrated winding with improved unequal teeth width topology is given.By comparing the performance characteristics of six-phase fault-tolerant motors with different pole-slot combinations,it is considered that the torque density of two coils per phase six-phase motor is maximum,which is more in line with the characteristics required by drive motor for electric vehicle.A rated speed of 900 rpm and maximum speed of 3600 rpm two coils per phase six-phase permanent magnet synchronous motor with surface mount rotor is designed by using finite element analysis software,of which the pole-slot combination is 18slot/10 pole.The influence of the motor structure parameters on its performance is analyzed and the motor is optimized based on the analysis result.The torque characteristics and the temperature distribution of permanent magnet at different rotating speeds are analyzed.The permanent magnet is optimized in blocks to reduce the eddy current loss of the permanent magnet,so as to ensure that there is no failure to permanent magnet.The efficiency map of the motor is calculated.The efficiency of the motor is over 93% at rated speed,and the highest efficiency is over 95%.The feasibility of the new scheme is verified.