Design And Analysis Of The Structure And Cooling System Of Double-stator Single-rotor Synchronous Motor

In recent years,the research of low-speed and high-torque Motors has been paid more and more attention in the field of motors.Rare earth permanent magnets have excellent magnetic properties,but their price is relatively high,which resulting in a higher cost than that of electric excitation motors.In order to obtain good electromagnetic performance,the geometric structure of conventional low-speed high-torque motors is mainly characterized by shorter axial length and longer radial length.The stator and rotor are mainly concentrated at the radial edge of the motor.Its internal space has not been fully utilized.This will lead to a low occupancy rate of space in the motor along the radius direction.In this paper,a new type of synchronous motor with double stator hybrid rotor structure is proposed.The motor is composed of internal and external stators and a single rotor composed of permanent magnet and magnetic barrier.Without increasing the volume of the motor,the space utilization and the output torque density of the traditional low-speed and high-torque motor are improved by making full use of the internal space of the motor.Meanwhile it reduces the use of permanent magnets and improves the performance-volume ratio of the motor.The work of this paper is as follows:Firstly,the general structure and operation principle of the synchronous motor are described.The stress field of the main parts of the new motor is analyzed by ANSYS WORKBENCH,and the force and deformation of each part of the motor are calculated under different rotational speeds.Secondly,mathematical and physical model of temperature field are established to calculate heat dissipation coefficient of the motor components.According to the difference of thermal conductivity of materials,the steady three-dimensional temperature field of the new dual-stator single rotor synchronous motor(external motor power :40 kW,internal motor power :20 kW)is calculated by finite element method.At the same time,based on the basic theory of heat transfer,the equivalent heat network method is used to establish the heat circuit calculation model of the motor.According to the heat transfer relationship of each part,the equations are listed,and the MATLAB program is compiled to calculate and solve the temperature of nodes in different positions.The results of finite element method and thermal network method are compared and analyzed.Finally,because the rotor and inner stator of a dual-stator motor are more difficult to dissipate heat naturally through the air,long-term heat accumulation can easily have a negative effect on the motor and affect the safety and service life of the motor.Therefore,the article uses air cooling and water cooling to reduce the motor temperature,and the air-cooled and water-cooled structures suitable for the synchronous motor were designed.The temperature of the spiral water channels with different cross-sectional shapes in the water-cooled structure was compared,and the effects of different cooling water speeds on the motor temperature were analyzed.