Research On Redesign Method Of Iron Core For Suppressing Torque Ripple Of Permanent Magnet Synchronous Motor

According to the improvement of the national energy-saving index of mechanical and electrical products,the increase of the load of permanent magnet synchronous motor and the service life of the motor,millions of motors will be eliminated in the future,resulting in great waste of resources.Motor remanufacturing can effectively solve the problem of resource reuse and raise the performance of the motor to the level of the original motor.For permanent magnet synchronous motors,torque ripple is a key factor that causes vibration and noise,which affects motor performance.Based on the characteristics of motor remanufacturing and the structure of other parts of the motor,based on the study of the causes of torque ripple caused by the motor,several cost-effective suppression methods are proposed.The work carried out is divided into the following aspects:(1)Comprehensively explained the background significance of the research,introduced the development of industrialization of permanent magnet synchronous motor for vehicles at home and abroad,analyzed the urgency of the development of motor remanufacturing industry,and the considerable development of amorphous motor,gave domestic and international research on remanufacturing and amorphous alloy applications in motors,expounded the methods of suppressing the torque ripple of permanent magnet synchronous motor proposed by scholars at home and abroad,and the advantages,disadvantages and application scope of each method were analyzed.(2)The mechanism and composition of torque ripple were analyzed,including cogging torque and ripple torque.Then,the torque ripple was analyzed by the mathematical model of the motor,and the cause of the ripple torque was obtained.For cogging torque,it is a kind of reluctance torque under no-load condition.It was analyzed by energy method,which provided a theoretical basis for redesigning the optimal design method of torque ripple of permanent magnet synchronous motor.(3)Based on the theoretical analysis and remanufacturing characteristics,the rotor core is redesigned,and a rotor redesign method based on the eccentric groove is proposed to effectively reduce the cogging torque of the permanent magnet synchronous motor for remanufacturing.In order to comprehensively optimize and reproduce the motor cogging torque and torque ripple,a progressive redesign method of single-pole inner eccentric groove,combined eccentric groove and magnetic bridge optimizationwas proposed,and the performance of remanufactured motor is improved.(4)According to the excellent performance of amorphous alloy materials with low loss,the influence of amorphous rotor on the performance of remanufactured motors was studied.The rotor of the same size made of amorphous alloy material replaces the rotor core of the used motor,and the output torque of the motor was increased.However,the cogging torque of the remanufactured motor was seriously increased,and the angle of the magnetic pole of the amorphous rotor was proposed.The external circle redesign method optimizes the torque performance and verifies the feasibility of the redesign method to reduce the cogging torque of the amorphous rotor.