| Permanent magnet synchronous motor(PMSM)has been widely used for its small volume,Light quality,high efficiency,flexible and varied in shape and size.With the development of industrial technology,capacity of PMSM is increasing,internal loss is also increasing,which leads to internal temperature of motor is getting higher and higher,directly affect reliable operation of motor.Therefore,it is very important that analysis and calculation of temperature field and design of cooling system.The temperature field of motors of two different cooling is analyzed by using different analysis methods of temperature field,and temperature field of PMSM with different cooling modes is analyzed accurately,choose the most suitable calculation method of temperature field for different practical conditions.Firstly,the 320 kW natural cooling PMSM is taken as an example,the loss of PMSM is analyzed and calculated by the method of formula calculation and Ansoft Maxwell software,especially the analysis and calculation of eddy current loss of permanent magnet.Based on the theory of heat transfer,the temperature field of prototype is analyzed by FEM,coupling analysis of electromagnetic field and temperature field was carried out by using ANSYS Workbench software.The importance of permanent magnet eddy current loss is verified by comparing the temperature field distribution of prototype with or without permanent magnet eddy current loss.Secondly,the temperature field of prototype is analyzed by LPTN,the nodes are arranged according to the radiating path of each part of motor,a network structure that can reflect the overall heat transfer of prototype is established,heat resistance of each node is calculated by the formula of heat conduction and thermal convection,write the program of heat balance equation by MATLAB,and calculate the temperature of each node in motor.Temperature of motor is tested,by comparing the results of FEM,LPTN and temperature rise test,we can see that the calculation results of LPTN and FEM are correct in the range of allowable error.Finally,water cooling system of 100 kW PMSM is designed.In order to solve the problem of leakage and heat dissipation in traditional cooling structure during the long term operation of motor,a new cooling structure is proposed.Calculate waterflow and velocity of motor when heat loss and heat dissipation are in equilibrium.The flow characteristics of cooling medium were analyzed by CFD,temperature field distribution of motor is obtained through the coupling analysis of fluid field and temperature field.The rationality and practicability of water cooling structure are verified by comparing temperature distribution of motor with or without cooling structure. |
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