| Permanent magnet synchronous motor(PMSM)is widely used in electronic information,rail transit,communication technology,aerospace,transportation and other fields because of its simple structure,high efficiency,high power factor and other advantages.Due to the variable frequency starting of the PMSM and the variety of application environments,it will bring a series of problems such as difficult heat dissipation,reduced efficiency,and reduced stability.Therefore,it is urgent to improve the output performance of the motor.In order to improve the output performance of the motor,to ensure the high-efficiency and stable operation of the motor,in this paper,taking the PMSM as the research object,respectively from the two aspects of electromagnetic field and temperature field of the motor are studied.The influences of armature winding number of turns and armature winding distribution mode,the inverter output voltage harmonic and its coupling,and the sleeve electromagnetic characteristics on the performance of PMSM are studied,by using the electromagnetic field and temperature field finite element method(FEM),decoupling analysis method and experimental method.Firstly,in order to comprehensively analyze the influences of the inverter output voltage harmonic on the PMSM,the electromagnetic performances of PMSM are studied,when the different harmonics orders,amplitudes,and phase angles are contained in voltage.The influence degree of the voltage harmonic on the electromagnetic field of the motor is determined,and the variation mechanism of the performance parameters of the motor is revealed.In addition,in order to further study the influence of harmonic voltage coupling on the torque ripple of the motor,the variation of harmonic voltage coupling on the torque ripple is obtained by using harmonic voltage coupling analysis.Finally,based on the theory of negative synergetic effect,the influence mechanism of different harmonic voltage coupling on the torque ripple of PMSM is revealed.A method to reduce the torque ripple of the PMSM is proposed,which provides a reference for the optimal design of PMSM under inverter power supply.Secondly,the application of semi-ferromagnetic sleeve in PMSM is studied.Taking the no-load electromotive force(EMF)as the research object,the optimal sleeve permeability of PMSM is determined by using the FEM,and the correctness is verified by using the analytical algorithm.In the analytical calculation process,in order to solve the calculation problem of the no-load leakage flux coefficient caused by the complex distribution of the pole-to-pole leakage flux,an iterative calculation method is proposed,and the electromagnetic field distribution of the motor is more accurately determined.Based on the optimization sleeve permeability,the variation of the eddy current loss with different sleeve conductivity is analyzed,and the optimal conductivity value could be determined.Finally,the variations of the current and power factor before and after optimization are compared and analyzed,and the influence of the sleeve electromagnetic characteristics on the motor performance is analyzed.The motor performance after optimization could be consistent with that of before optimization by reducing the thickness of the permanent magnet,and it also provides a theoretical basis for the optimization analysis of energy and material saving of the PMSM.Finally,aiming at the special requirements of PMSM performance caused by the diversity of applications,the structural parameters that affect the electromagnetic performance of PMSM are optimized.The variation of armature winding number of turns and armature winding distribution mode on motor performance such as armature current,torque ripple,losses,and temperature rise is determined,and the influence mechanism is revealed,which provides a theoretical basis for the design of structural design of PMSM. |
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