Research On Optimal Design Of Interior Permanent Magnet Synchronous Motor Based On Particle Swarm Optimization

Interior permanent magnet synchronous motor(IPMSM)is a radial flux permanent magnet motor with special structure of rotor components,which has the characteristics of high efficiency,high power density and strong load capacity.Compared with the common surface.mounted permanent magnet synchronous motor,the rotor components of the interior permanent magnet synchronous motor have strong mechanical stability.It can operate stably and reliably under the conditions of higher speed demand and wider speed range.Therefore,the interior permanent magnet motor has been widely used in electric vehicles,intelligent drive,aerospace military industry,industrial servo and other fields.In this paper,the electromagnetic design and simulation of the interior permanent magnet synchronous motor are mainly carried out,and an unequal thickness spindle eccentric permanent magnet pole structure is proposed to optimize the performance of the motor.According to the equivalent magnetic circuit model of the interior permanent magnet synchronous motor combined with particle swarm optimization algorithm,the cost optimization and performance improvement of the existing 5.5 k W interior permanent magnet synchronous motor are studied.(1)In order to realize the practicability of engineering application.The design method and process of interior permanent magnet synchronous motor are studied.In this paper,the common topology of the interior permanent magnet motor is given.According to the electromagnetic calculation formula of the permanent magnet motor,a series of empirical parameters are selected and combined with the equivalent magnetic circuit method.The main design parameters of the motor are obtained,and the finite element simulation model is built according to the design parameters.The values of the main design parameters are modified and adjusted according to the simulation results until the final electromagnetic design parameters meet the established requirements.(2)In order to obtain the better performance of the interior permanent magnet synchronous motor,on the basis of 12 slot 10 level traditional interior permanent magnet synchronous motor,this paper proposes a unequal thickness spindle eccentric permanent magnet pole structure.Taking the sinusoidal air gap flux density and cogging torque as the optimization objectives,the analytical model of air gap flux density of unequal thickness spindle eccentric magnetic pole structure is given.The equivalent magnetic circuit model of the internal permanent magnet synchronous motor is derived,and the Matlab script programming is written to solve the calculation.The finite element analysis software is used for simulation.The calculation and simulation results show that the unequal thickness spindle eccentric magnetic pole structure can effectively improve the sine degree of the no load air gap flux density waveform of the motor,and reduce the cogging torque.(3)In order to reduce the production cost of the motor and improve the comprehensive performance of the motor,based on a known 18.slot 6.pole 5.5 k W interior permanent magnet synchronous motor,according to the equivalent magnetic circuit model and structural characteristics of interior permanent magnet synchronous motor,this paper deduces the motor cost function and the maximum electromagnetic torque expression of the motor.The PSO algorithm with variable weight coefficient is introduced,and six structures and electromagnetic parameters,including the air gap length of the motor,the length of the stator core,the diameter of the stator winding and the turns of each slot winding,the stator slot type parameters and the width of the permanent magnet,are selected as the optimization variables.The motor efficiency,rated torque and slot full ratio are taken as the constraint conditions.The material cost and the maximum electromagnetic torque of the motor are taken as the optimization objectives,and the optimization results are compared and analyzed.The results show that under the premise that the performance of other motors meets the requirements,the optimization results show that the maximum electromagnetic torque of the motor is increased while the motor cost is reduced.(4)To verify the correctness and rationality of the optimization.The three dimensional model establishment and two dimensional drawing of the optimized 18.slot 6.pole 5.5 k W interior permanent magnet synchronous motor were completed.The prototype test platform was built,and the test results and simulation results of the prototype were comprehensively analyzed.At the same time,in order to verify that the heating of the optimized motor does not exceed the allowable range of temperature rise,the optimized parameter generated motor model was imported into Motorcad software for steady state thermal analysis under rated load to further verify the feasibility of the optimization process and the correctness of the optimization results.