Temperature Field Analysis Of Dual-Redundancy Permanent Magnet Synchronous Motor Based On Equivalent Thermal Network Method

This paper was based on the project of “Dual-Redundancy Permanent Magnet Synchronous Motor(DRPMSM)with low thermal coupling and none electromagnetic coupling between adjacent two phase windings” which supports by National Natural Science Foundation of China.A prototype of 56 kW was produced,analytical method and finite element method were used to analyze its electromagnetic characteristics,the equivalent thermal network method and finite element method were used to analyze its steady temperature field.After that,the equivalent thermal network method was used to analyze the factors affecting the temperature distribution of DRPMSM.The main parameters,structural characteristics,material characteristics,no-load characteristics and load characteristics of DRPMSM were comprehensively analyzed.The steady state temperature rise of DRPMSM was calculated by equivalent thermal network method.The steady equivalent thermal network model with 52 nodes of DRPMSM was established according to it’s structural characteristics.This model took into account of the isolated teeth and 2-layer-winding model,and the air gap between the stator and rotor was equivalent.The heat transfer coefficient of the end surface of stator and rotor were calculated,the thermal conduction resistance and convection heat resistance between each node in the model were calculated.The heat balance equation was established and solved by MATLAB.The steady temperature rise of the nodes of DRPMSM was obtained.The steady state temperature field of DRPMSM was simulated by finite element method.The structure model of DRPMSM was established by Pro/E,it includes the equivalent model of the components and the fluid region of the motor.Reasonable division of each part was carried out,the boundary conditions of thermal conductivity of solid part,convective heat transfer coefficient of fluid and solid surface were determined.Three dimensional steady temperature field of DRPMSM was obtained by ANSYS/Workbench simulation.The result of steady-state thermal rise was solved by MATLAB and compared with the steady-state temperature field solved by finite element method,the result of equivalent thermal network method agreed well with finite element method.Moreover,the equivalent thermal network method improves the calculation speed and shortens the design cycle of this kind of motor.The influence of wind speed on shell surface and shell material on the temperature rise of the motor was compared,which provides a theoretical basis for the design of the same kind of motor and the selection of cooling mode.