Research On Multi-physics Optimization Design Of Novel Seven-Phase In-wheel Motor

Compared with traditional three-phase motors,the multi-phase permanent magnet motor has the characteristics of small torque ripple,high fault-tolerant capability,high power density,high torque density and high efficiency,making it particularly suitable for low-voltage high-power,high-performance and high-reliability applications,such as aerospace,marine power propulsion,multi-electric aircraft and electric vehicles.This paper takes electric vehicles as the application target and takes the novel type of in-wheel motor with fractional slot concentrated winding(FSCW)as the research object.The following work has been done:the design of multi-phase FSCW,motor structure design,multi-physics analysis and prototype design and processing:Firstly,a unified mathematical model of multi-phase FSCW is established by using the winding function theory,and the method of reducing winding magnetomotive force(MMF)harmonics is studied and proposed,and the effectiveness of the proposed method is verified by finite element simulation.Secondly,on the basis of the original two-rotor axial flux motor,a novel structure of three-rotor composite flux seven-phase in-wheel motor is proposed.A seven-phase FSCW was designed using the stator slot shifting method,and the implementation method of toroidal FSCW was studied.An electromagnetic analytical model was established for the novel motor,and the relationship between the initial dimensions of the prototype was determined.Then,the multi-physics finite element model of the novel seven-phase in-wheel motor was established to verify and adjust the initial design,including:using the electromagnetic field model to analyze and adjust the initial magnetic network design;using the temperature field model to verify the temperature distribution of the motor under different operating conditions;the design of the stress field finite element model was used to verify the design of the silicon steel sheet magnetic bridge width at high speed;the radial force wave and the vibration mode of the motor were analyzed to avoid mechanical resonance in the operating area of the motor.According to the results of multi-physics analysis,the processing scheme of the prototype was determined,and the prototype was successfully produced.Finally,the content of the full paper research is summarized and the future prospects of the research are presented.