Thrust Optimization And Temperature Field Analysis Of Submersible Linear Motor

In view of the fact that the working environment temperature of the submersible linear motor is high and the variation range is large,in order to improve the thrust of the motor,reduce the thrust fluctuation of the motor and reduce the influence of permanent magnet demagnetization on the thrust performance of the motor,the structural parameters of the motor are optimized based on the response surface method.The temperature rise characteristics of the motor are analyzed,and the results show that the stator winding temperature and the permanent magnet temperature are within the working temperature range,and the motor can operate stably.The main research content and achievements of the thesis include the following aspects:First of all,the structure of the submersible linear motor is designed to establish a finite element electromagnetic model of the motor.Finite element analysis is performed on the motor’s air gap magnetic density,no-load back EMF,cogging force,thrust,stator tooth magnetic density and other motor properties.Secondly,through finite element simulation,the influence of motor structure parameters on the thrust performance of the motor is analyzed during the normal state of the permanent magnet.Considering the high temperature working environment of the motor,through the analysis of the characteristics of the SmCo28H permanent magnet,it can be seen that the knee point of the permanent magnet demagnetization curve is 0.9Br.When the permanent magnet is demagnetized by 10%,the influence of motor structure parameters on the thrust performance of the motor is simulated.Through the analysis,it can be seen that the permanent magnet thickness,air gap width,permanent magnet width and slot width have a greater impact on the thrust performance of the motor,and changing the structural size can reduce the influence of permanent magnet demagnetization on the thrust of the motor,and also obtain the optimal value range of the main structural parameters,laying the foundation for the optimization of the structural parameters later.Then,based on the response surface method,a mathematical model of the motor thrust and thrust fluctuations,as well as the thrust change value at demagnetization,is established on the structural parameters of the motor.Through the multi-target genetic algorithm,the solution of maximizing the thrust of the motor,the minimum value of thrust fluctuation and thrust change during demagnetization is obtained,and the finite element simulation of the motor before and after optimization is performed.Compared with before optimization,the average thrust of the motor increased by 14.95% and the thrust fluctuation was reduced by 63.39% compared to before optimization.When demagnetizing,the motor thrust change decreases.Finally,Thermnet is used to establish a two-dimensional temperature field model of the motor,and the thermal parameters of the motor are analyzed and calculated,the transient and steady-state temperature fields of the motor are finite element analysis,and the windings and permanent magnet temperature of the motor slot are analyzed.The results show that the temperature of the winding and the permanent magnet are within a reasonable range,the temperature field distribution of the motor is reasonable,and the motor can operate stably for a long time.There are 38 figures,12 tables and 70 references in this paper.