Analytical Modeling And Analysis Of The Magnetic Field Of A Built-in Permanent Magnet Motor Considering The Saturation Of The Magnetic Isolation Bridge

Permanent magnet motors have the advantages of simple structure,reliable operation and high power density,so they are widely used in various fields including aerospace,national defense and daily life.The magnetic field is the medium of energy conversion inside the motor.The establishment of an accurate permanent magnet motor magnetic field analysis model is the prerequisite and basis for the design of high-performance motors.This paper focuses on the calculation of the magnetic field of the interior permanent magnet motor(IPM)and the reduction of the torque ripple of the motor.The magnetic field analytical modeling method of the interior permanent magnet motor and the influence of the motor rotor magnetic bridge structure on the motor torque ripple are studied.The research results obtained are as follows The interior permanent magnet motor magnetic field analysis calculation and improvement of the interior permanent magnet motor performance provide new ideas.First of all,in view of the complex structure of the rotor of the interior permanent magnet motor,it is difficult to directly model analytically in the polar coordinate system,and the problem of nonlinear magnetic saturation in the magnetic bridge region of the rotor,this paper proposes a method that can accurately consider the magnetic saturation of the magnetic bridge,and this method is based on the principle of flux invariance,and the geometric structure of the interior motor is equivalently transformed to make it easier to model in the polar coordinate system.According to the different degrees of magnetic saturation in the magnetic bridge area,the magnetic bridge subdomain and the bridge saturation overflow subdomain are established respectively,and the relative permeability values of the two subdomains are solved by the iterative permeability method.Then in order to reduce the torque ripple of the interior permanent magnet motor,this paper proposes an optimization design method for the rotor magnetic bridge structure to reduce the torque ripple of the interior permanent magnet motor.Based on the Taguchi method,the low torque ripple design of the interior permanent magnet motor is realized,and the influence of the structural parameters of the rotor bridge on the torque ripple of the motor is revealed.Finally,taking an 18 k W interior permanent magnet motor as an example,the prototype is verified by experiments using the proposed analytical modeling method.The results show that the analytical model has obtained more accurate magnetic field analytical calculation results under various conditions of no-load and load.