Research On High Torque And Cost-effective Permanent Magnet Assisted Synchronous Reluctance Motor For Electric Vehicles Based On Torque Ripple Optimization

The domestic electric vehicle industry is thriving due to policy inclination and people’s increased awareness of environmental protection.Among them,A0 and A00 class electric vehicles have good market prospects due to their low prices and convenient travel.In order to reduce their production costs and improve their Competitive advantage.Starting from the motor itself,this paper designs a permanent magnet-assisted synchronous reluctance motor with lower torque ripple and higher torque cost performance.First,take a permanent magnet synchronous motor for electric vehicles as a prototype,redesign its rotor,use neodymium iron boron and ferrite hybrid excitation,and study the torque performance of the two permanent magnets at each pole.Asymmetrical arrangement of hybrid permanent magnets with lower torque ripple is proposed.Eight parameters including the rotor rib parameters,the distance between the rotor air magnetic barrier and the weight reduction hole,the amount of three permanent magnets,and the length of the air gap are selected,and the rotor structure is parameterized and optimized.Then,according to the parameterized optimization results,an asymmetric permanent magnet-assisted synchronous reluctance motor rotor structure is proposed,which uses two types of permanent magnets for hybrid excitation.The finite element simulation of the motor using the rotor structure was carried out,and the peak torque,torque ripple,cogging torque,no-load back EMF and no-load air gap flux density were simulated.In addition to the reduced peak torque,other performance parameters are superior to the original permanent magnet synchronous motor.Finally,a 28 kW prototype with the above-mentioned rotor structure was made.An experimental platform was built using a new energy motor test bench.The external characteristics,efficiency MAP under electric state,no-load back EMF,and the temperature rise under the rated operating conditions of the motor was tested.And the cost and torque cost performance of the motor were estimated,which verified that the hybrid permanent magnet assisted synchronous reluctance motor proposed in this paper has lower torque ripple and higher torque cost performance.It is more suitable for driving motors of A0 and A00 class electric vehicles.