| In order to overcome the disadvantage of uncontrollable magnetic field and narrow speed range of traditional permanent magnet synchronous motor(PMSM),a Mechanical Controllable Leakage Flux Permanent Magnet Motor(MCLFPMM)is proposed in this research.MCLFPMM is composed of the traditional permanent magnet motor body structure and a mechanical flux-adjusting device attached to the rotor side,which can change the airgap magnetic field by using the centrifugal force at high speed,realize the automatic adjustment of leakage flux,and effectively broaden the speed range of the motor.MCLFPMM is taken as the research object in this thesis,whose structure characteristics and operating principle are analyzed,and the coordination law between the flux-adjusting device and the motor body is deeply explored.The parameters of two rotor topologies of the motor are optimized,and the comprehensive performance of the two optimized rotor topologies is compared and analyzed to determine the optimal rotor topology.The electromagnetic characteristics,mechanical characteristics,electromagnetic vibration characteristics of the structure are fully simulated and analyzed by using finite element method,which provides some theoretical and technical support for the application of this kind of MCLFPMM in the field of electric vehicles and constant power wide speed drive motors.The main research contents of this paper are as follows:(1)The operating principle and dynamic simulation analysis of MCLFPMM.The two topologies of MCLFPMM are introduced,namely,Single-Layer Permanent Magnet Mechanical Controllable Leakage Flux Motor(SLPM-MCLFM)and Double-Layer Permanent Magnet Mechanical Controllable Leakage Flux Motor(DLPM-MCLFM).The working principle of MCLFPMM is analyzed and the mathematical model of MCLFPMM is deduced.The dynamic simulation analysis is carried out by ADAMS software,and the change law between the self-rotation angle of the permanent magnet of MCLFPMM and speed is obtained,which verifies the validity of the design of the flux-adjusting device.(2)Two rotor topologies of MCLFPMM are optimized.With high output torque,low torque ripple and cogging torque as the objectives,the multi-objective optimization analysis of the rotor structure parameters of SLPM-MCLFM and DLPM-MCLFM are carried out by comprehensive sensitivity analysis method,response surface optimization method and continuous nonlinear programming method,and the optimal rotor structure parameters are obtained.The comprehensive performance of the optimized SLPM-MCLFM and DLPMMCLFM is compared,and the SLPM-MCLFM is determined to be the optimal rotor topology for the flux-adjusting device.(3)The electromagnetic and mechanical properties of SLPM-MCLFM are compared and analyzed.The electromagnetic properties of traditional motor and SLPM-MCLFM are compared and analyzed based on the finite element method.The simulation results show that SLPM-MCLFM has better flux-weakening ability,wider speed range and lower irreversible demagnetization risk of permanent magnet.In addition,the mechanical strength of SLPMMCLFM and the traditional motor at highest speed is verified,and the stress and deformation of the two motors at different speeds are obtained.(4)The simulation analysis of electromagnetic vibration characteristics is carried out.Three-dimensional modal simulation models of different stator systems of motor are constructed,and the influence of the related components of the stator system on the natural frequency of the motor structure is studied.Based on the electromagnetic vibration analysis mechanism,the spatial distribution and spectrum characteristics of the radial electromagnetic force wave of SLPM-MCLFM and traditional motor under different operating conditions are simulated and analyzed;the radial electromagnetic force obtained from electromagnetic field is coupled to structural field for harmonic response analysis.The vibration acceleration spectrum characteristics of SLPM-MCLFM and traditional motor under different operating conditions are obtained. |
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