Research On Cooling Of High Power Density Medium Voltage Asynchronous Motor

Medium voltage Induction Motors have been widely used and become the core drive device in mining,metallurgy,chemical industry,energy,environmental protection and other fields for their technical and economic performance.With the continuous improvement of material and manufacture,as well as the further development of fine design of motor,the power density of the medium voltage asynchronous motor is also increased,which is very useful to improve the economy of the system and the unit.But the increase of the power density of the medium voltage induction motor will increase the loss density of the motor,which will have a negative impact on the cooling.The temperature rise of the motor will be too high,affect the safe operation,and produce bad safety hidden trouble to operating system.Therefore,combined with the electromagnetic loss parameters of high power density medium voltage induction motor,the research on the cooling of the motor is of great significance for the safe operation.Taking a 1800 kW medium voltage asynchronous motor as an example,the electromagnetic parameters of the motor are calculated by magnetic circuit method,two-dimensional finite element method and three-dimensional finite element method respectively,the loss distribution of the motor is obtained,and compare the calculated results of different methods to propose a fast and efficient engineering design method and calculation process.Secondly,based on the basic principles of computational fluid dynamics(CFD)and numerical heat transfer(NHT),a three-dimensional fluid-heat coupling model is established for the study of the cooling structure of the prototype,and the loss distribution obtained from electromagnetic calculation is used as the heat source load.Combined with the operating conditions of the motor,the finite volume method is used to numerically analyze the cooling air flow characteristics and the overall heat transfer characteristics of the motor by applying reasonable boundary conditions to the established solution domain model.The flow field distribution and temperature field distribution in the solution domain are obtained,and the calculated results are compared with the experimental data to verify the correctness of the calculation method and the reasonableness of the imposed boundary conditions.