Research On Flow And Heat Coupling Of Low-Speed And High Torque Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor usually runs under high load,which leads to serious heating of the motor.Therefore,it is of great significance to accurately calculate the temperature distribution of the motor and reasonably design its cooling and cooling structure to prevent the motor from overheating and improve the operating life of the motor.Aiming at the technical difficulties of high temperature rise caused by high torque density of low-speed high-torque PMSM during operation,this dissertation takes a low-speed high-torque PMSM of 160 k W and 60r/min as an example,establishes a temperature field calculation model according to the actual geometric size of the motor,and calculates the loss distribution of its components through finite element method.The heat source is applied to each part of the motor to carry out the simulation calculation of the temperature field,and the temperature distribution law and internal fluid flow characteristics of each part of the motor are obtained.Finally,for the parts with higher temperature rise,different cooling measures are taken inside the motor to optimize them.Firstly,based on the theory of fluid flow and heat transfer,a mathematical model of the motor is established.Combined with the actual size and cooling structure of the motor,a calculation model of the temperature field of the motor is established by applying reasonable basic assumptions and boundary conditions,which provides a foundation for the coupled calculation of the fluid and heat of the motor.On the basis of the loss mechanism of the components of low-speed permanent magnet motor,the loss under rated load is calculated,and the distribution of the loss of each component is obtained.Secondly,through the calculation of the temperature field of the motor,the temperature distribution law and internal fluid flow characteristics of each part of the motor are obtained,and the temperature rise trend of each part along the axial direction is analyzed in detail.It is found that the local hot spot of the motor is located at the end of the stator winding,The rationality of the method and the accuracy of the simulation results are verified.Finally,aiming at the problem of high temperature rise of permanent magnet,the influence of different sizes of wind spurs on fluid field and temperature field of motor was explored by adding cooling spurs at the end of rotor core for simulation analysis.The best size of wind spurs for cooling effect was obtained,which reduced the temperature rise of permanent magnet by 4.2K.Due to the high temperature in the stator winding end,in order to prevent them from overheating affect insulation performance,through between the casing and winding overhang potting heat conduction glue way to reduce the winding temperature rise,the simulation analysis of the different ways of potting and the influence of different types of heat conduction glue on the motor heat transfer,found a way of filling and sealing of winding scheme of heat transfer effect is best,the temperature rise decreased 7.1K,With the increase of the thermal conductivity coefficient of the thermal conductive adhesive,the heat transfer effect of the winding gradually becomes smaller.