Harmonic Analysis And Low Loss Design Of FSCWs PM Motors Based On Magnetic Field Modulation

The development of new energy vehicles and all-electric aircraft presents refined demands on motion control systems.As an important part of the field of motion control,permanent magnet motor has become a research hotspot to improve the stability of control systems.The fractional-slot concentrated winding permanent magnet motor is highly concerned by the field of motion control due to its high efficiency,high output torque and high fault tolerance.However,compared with the integer slot,the magnetomotive force harmonic content of the distributed winding of the fractional slot is rich,which causes problems such as vibration,noise and electromagnetic loss.Based on the principle of magnetic field modulation,the harmonic content of the magnetomotive tooth is reduced by adding the stator modulation tooth.Based on the harmonic order generated by the modulated magnetic field,the generality of the slot matching which can reduce the eddy current loss of the stator and rotor magnetic field modulation motor is summarized.Finally,the stator-rotor magnetic field modulated motor with fractional slot concentrated winding was designed and manufactured.The theoretical basis for further studying the influence of magnetic field modulation theory on the harmonics and losses of permanent magnet motor was established.The main contents of this paper are as follows:1? Taking the reduction of magnetomotive force harmonic content as the research goal,the existing methods of harmonic attenuation and low loss design are analyzed and summarized from two aspects of changing winding factor and magnetic field modulation.Some problems are raised in this section.2? Based on the analytical method,the magnetomotive force of single-phase winding and the magnetomotive force of three-phase composite winding are analyzed.The magnetomotive force harmonic content of the winding is discussed.Using the magnetic field modulation principle,the magnetomotive force permeability model is established,and the air gap flux density of the modulated magnetic field is derived.3? The method of low-tooth harmonic design is studied from the aspect of stator structure.A new stator structure capable of effectively reducing rotor eddy current loss and motor vibration noise is proposed in the stator.And use finite element to verify.4? Introduce the principle of magnetic field modulation,and analyze the magnetomotive force and magnetic flux density of the fixed rotor magnetic field modulation motor.According to the relationship between the fixed rotor number,the number of permanent magnet pole pairs and the number of winding pole pairs,the slot matching which can effectively reduce the eddy current loss of the motor is summarized and summarized.The number of fixed stator slots is selected,and a preliminary model of the stator-rotor magnetic field modulation motor of the fractional-slot concentrated winding is established.5? Determine the parameters according to the basic size requirements of the motor.Based on the finite element analysis,the motor back EMF,output torque,loss and instantaneous temperature of different slot matching are compared.6? Design the prototype and build a digital experimental platform.Select the control strategy,test the prototype,compare and analyze the experimental values and simulation values,and verify the theoretical analysis through experimental tests.