Optimization And Design Of Surface Bearingless Permanent Magnet Motor

With the continuous improvement of industrial capacity,electric motors as the heart of various mechanical equipment,have received wide attention.Compared with the traditional permanent magnet motor,the bearingless permanent magnet motor has the characteristics of frictionless,small size,compact structure,high power density.Because of its superior features,it has a very broad application prospect in the fields of medical equipment,aerospace and flywheel energy storage.In this paper,a surface bearingless permanent magnet motor is optimally designed.Compared with conventional permanent magnet motors,bearingless permanent magnet motors need to improve the suspension performance in addition to the torque performance,so the torque and suspension parameters need to be considered in the design process.In this paper,Taguchi method and response surface method combined with genetic algorithm for multi-objective optimization are used to optimize the motor structure.The work contents and achievements of this paper are as follows:1.An analysis of the bearingless permanent magnet motor’s operating mechanism is followed by the completion of the surface bearingless permanent magnet motor’s initial design scheme in accordance with the motor structure design formulas and experience,as well as the motor’s rated parameters and characteristics.A twodimensional electromagnetic field simulation model is created using finite element software in accordance with the surface bearingless permanent magnet motor’s initial design plan.The air gap magnetic density,magnetic density distribution,and magnetic force line distribution of the motor are examined based on the simulation findings to confirm the validity of the motor’s original design plan.2.The multi-objective optimization design of the motor structure parameters is initially implemented by Taguchi method in order to enhance the torque and suspension performance of the surface bearingless permanent magnet motor.Air gap length,permanent magnet thickness,pole arc coefficient,and slot breadth of motor are used as optimization factors because they have a significant impact on the torque and suspension performance.The motor torque,suspension force and suspension pulsation are effectively improved compared with the initial design scheme after optimization by Taguchi method.The feasibility of Taguchi method optimization is verified by simulation experiments.3.Taguchi method design experiment method has the characteristics of short design cycle,low experimental cost and high applicability,but there is a certain limitation for the range of optimized parameters.In order to further enhance the performance of the surface bearingless permanent magnet motor,the In this paper,the worldwide range of the motor structure parameters is optimized by using the response surface technique in conjunction with the genetic algorithm for multi-objective optimization.Four optimization variables,namely air gap length,permanent magnet thickness,pole arc coefficient and slot width,are simulated in the finite element software for torque and suspension performance according to the experimental design table,and a response surface model containing three optimization objectives and four optimization objectives is established according to the experimental results.The optimum design solution was obtained by comparing the optimal findings of the response surface-multi-objective genetic algorithm optimization with those of the Taguchi method optimization and the initial design solution.