Low Harmonic Design And Electromagnetic Performance Analysis Of Flux Reversal Permanent Magnet Motor

Electric vehicles have the advantages of low noise,no pollution,and high energy efficiency,so they are highly favored by the automotive industry and the public.As a key component of the vehicle’s power system,the driving motor has a significant impact on the vehicle performance.Flux reversal permanent magnet(FRPM)motor maintains the advantages of traditional stator permanent magnet motors,such as easy cooling,simple rotor structure and fast acceleration and deceleration response.However,the FRPM motor usually uses fractional slot concentrated windings,which leads to problems such as complex armature magnetic field harmonics,large torque ripple,low efficiency and power factor.Based on the principle of magnetic field modulation,this paper introduces a low-harmonic design method,proposes a low-harmonic flux reverse permanent magnet(LH-FRPM)motor,and provides a theoretical basis for low-harmonic design.The core idea of low-harmonic design is to calculate and analyze the number of pole pairs,rotation speed and steering of the permanent magnetic field and armature magnetic field from the perspective of magnetic field modulation,and then make judgments on the working harmonics and invalid harmonics.By introducing two sets of new three-phase windings,the special combination design of the position space angle,the current time angle and the rotor modulation angle between the two sets of new three-phase windings is used to effectively reduce the invalid harmonics of the armature magnetic field.Firstly,the paper analyzes the motor topology,operating principles and feasible slot-pole combinations,and derives the power output equation.Secondly,the main structural dimensions of the motors were parametrically modeled,the optimal design parameters were obtained,and the motor materials and winding design methods were determined.Then,the finite element method is used to analyze and compare the electromagnetic performance of the two motors in detail.Combining iron loss,permanent magnet eddy current loss and winding copper loss,calculate and compare the efficiency of the two motors.Finally,the related simulation analysis of the motors temperature field is completed.The research shows that the low-harmonic design effectively reduces the torque ripple of the motor,reduces the core loss and permanent magnet eddy current loss,improves the operating efficiency and power factor,and helps to reduce the motor vibration and noise,and suppress the motor temperature rise.