High-speed Bearingless Switched Reluctance Motor Design And Vibration Damping Analysis

In the background of China’s carbon peak and carbon neutral,the development of electric motors has paid more attention to high efficiency and energy saving.Bearingless Switched Reluctance Motors(BSRM)are widely used in flywheel energy storage,aerospace and other high-speed fields with the advantages of low loss and fast speed.However,the unique convex pole structure of BSRM causes large torque pulsation in the motor,which not only reduces the continuous operation performance of the motor,but also shortens its high-speed operation life.To solve these problems,a high-speed12/8-pole double-winding BSRM is designed in this paper,and the details of this work are as follows:Firstly,the main structure and working principle of BSRM are analyzed,and the mathematical model of torque and suspension force of BSRM is established by using the virtual displacement method.Based on the structural characteristics of BSRM,the design formula of basic dimensional parameters is derived,and the initial structural dimensions of BSRM are calculated by combining the previous design experience,which lays the foundation for the subsequent analysis of structural optimization and vibration and noise characteristics of the motor.Secondly,by analyzing the suspension characteristics and torque characteristics of the motor,it is verified that the motor has good operating performance.In order to optimize the torque performance of the high-speed bearingless switched reluctance motor and solve the problem of large torque pulsation caused by the biconvex pole motor structure,a stator helical tooth structure that can reduce torque pulsation during phase change is proposed based on the mathematical model of torque and levitation force.A12/8-pole double-winding BSRM with a helical tooth structure is used as the research object,and a general solution formula for the slope range of the tooth end of the stator helical tooth is derived.The motor performance before and after optimization is analyzed to verify the effectiveness of the method.Finally,the radial electromagnetic force analysis of the optimized helical tooth structure BSRM is carried out to provide analysis data for vibration simulation.And then,import the 3D model of BSRM stator with oblique tooth structure in Workbench field,analyze the vibration mode and inherent frequency of the motor,use the method of magnetic-solid weak coupling to load the radial force analysis results in Maxwell to the stator teeth in the vibration field,perform harmonic response analysis on the vibration displacement and vibration acceleration of the motor,and then load the vibration analysis results as excitation to the noise field,analyze the sound pressure cloud of the motor at different frequencies and the sound pressure level cloud.Finally,in order to optimize the vibration and noise characteristics of the motor and reduce the radial electromagnetic force inducing the vibration of the generator,the influence of the motor structure parameters on the radial suspension force and the radial electromagnetic force are analyzed separately,and the stator outer diameter,rotor inner diameter,rotor yoke thickness and rotor pole arc are taken as the parameters to be optimized.On this basis,the expression of the radial electromagnetic force function is fitted by the data analysis software SPSS,and the optimal structural parameters are obtained based on the Particle Swarm Optimization(PSO)algorithm.The simulation of the optimized oblique tooth BSRM is carried out to compare the vibration and noise performance and suspension force of the motor before and after the optimization,which proves the feasibility of the proposed optimization scheme.