Research On Operation Efficiency Optimization Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motors are widely used in hybrid vehicles,rail transit,elevators,medical equipment,petroleum industry and many other fields because of their high efficiency,high power density,high response,and easy control.The improvement of the control efficiency of permanent magnet synchronous motors can effectively reduce energy consumption,which is of vital importance to the solution of energy conservation,emission reduction and global greenhouse effect problems.Therefore,this article takes the surface-mounted permanent magnet synchronous motor as the research object,and conducts the following research on how to improve its operating efficiency.Firstly,by analyzing the loss source of permanent magnet synchronous motor(PMSM),the mathematical model of PMSM considering iron loss is established by using the method that the iron loss is equivalent to the heating on the resistance,and its effectiveness is verified by Matlab/Simulink simulation platform.Secondly,by analyzing the internal relationship between the total loss of the motor in the steady state and the stator current,it is concluded that the efficiency of the motor in the steady state changes with the direct axis current in a convex function.Next,in order to find the optimal efficiency point of the motor,on the basis of comparing the advantages and disadvantages of the two efficiency optimization methods,the fixed-step search method and the golden section search method,a golden section search efficiency optimization strategy based on back-step adaptive control is proposed and verified by simulation.It is proved that this strategy can optimize the steady-state efficiency of the motor,and solve the problem of speed and torque fluctuation caused by the change of the direct-axis current in the optimization process.Finally,in order to increase the speed of efficiency optimization and reduce the motor loss in the optimization process,a search algorithm improvement strategy based on fixed model parameters is proposed and verified by simulation.This strategy uses the suboptimal stator obtained by the model method(LMC)to determine the initial search interval of the search algorithm to make the motor quickly run to the vicinity of the optimum point and quickly converges to the optimum point of efficiency.The simulation results show that this strategy has good dynamic performance and steady-state performance,and it can effectively reduce the loss of the motor in the process of optimization.At the same time,for some specific occasions,the strategy can further improve the efficiency optimization speed.