Design And Heat Calculation Of Low Speed High Torque Permanent Magnet Synchronous Motor

In the coal mining industry,the low speed with high torque permanent magnet motor is used to replace the traditional asynchronous motor,it can reduce noise and unnecessary energy loss,also can improve the efficiency of the transmission system.It has a wide application prospect in heavy load field such as coal mine.In order to improve the material utilization,reduce the cost of the motor and increase the torque density of the motor,there is often using high electromagnetic load,this leads to higher temperature rise of the motor,therefore,the high heat dissipation is required for the motor,the air cooling system is not enough to meet the motor's heat dissipation,therefore an efficient cooling system,it is very important for the heat dissipation of the motor.This paper designs a permanent magnet synchronous motor with low speed high torque for the mine use.At the same time,the comparison of the common cooling system based on the field quantity of the motor is given,summarize their strengths and weaknesses,and the cooling system of the motor is designed,finally,the temperature field of the motor is analyzed and calculated.First of all,design a low speed with high torque permanent magnet synchronous motor with the parameter of 355 kW,the efficiency of 90% or higher,rated speed at 90r/min,including the choice of main dimensions,the form of magnetic circuit and machine groove cooperates,and also the electromagnetic calculation software is used to analyze the electromagnetic field of the designed motor.Secondly,in view of the widely used water cooling structure: the axial structure and circumferential structure and also the multiple parallel branch cooling structure modeling,ensure the heat dissipation area are same for the three kinds of cooling structure,based on the fluid calculation software use the methods of thermal-fluid-solid coupling to analyse the three kinds of cooling structure,comparing the temperature field,velocity field and so on,analyzed the advantages and disadvantages of three kinds of cooling structure.For the conclusions from the comparison of the cooling structure above,considering the proper cooling structure for the motor,analyzing the process of the waterway design,based on the knowledge of computational fluid dynamics and heat transfer,designed the cooling system for the motor.Finally,for the cooling system that has been designed,create the three dimension model,based on the Fluent software using the finite volume method to analyse the temperature of the motor,then improving the electromagnetic scheme and cooling system of the motor.Finally,the factors that affecting the heat dissipation for the motor are studied,including the fluid flow state,the initial temperature of the water,as well as the influence of the different heat transfer coefficient of the potting of the motor.