Global Temperature Rise Prediction Of Pmsm Based On Bidirectional Hydraulic-Thermal Network Coupling

Due to the advantages of compactness,effectiveness and conveniently starting,high-voltage line-starting permanent magnet synchronous motor（LSPMSM）is widely applied with square drop torque load.However,the increasing application have brought about increasing requirements for motors such as high speed,high torque density and high power density.Therefore,the temperature rise of the motor is a serious issue,which obviously affects the performance and reliability of the motor.The accurate prediction of temperature rise is important before performing a reliable motor design.Firstly,the pressure drop balance equation of each hydraulic loop and the flow conservation equation of each hydraulic node were given based on the basic equations of fluid flow.Considering the special structural characteristics of the motor with axial and radial ventilation cooling,the global hydraulic network model of the motor was established by modeling the indentor elements and hydraulic resistances.The flow distribution of cooling air was obtained by solving the mentioned model with network matrix method.Then,the heat conservation equation of each thermal node was given based on the basic equation of heat transfer.The electromagnetic losses of LSPMSM were calculated based on the finite element analysis of electromagnetic field,which was considered as the heat source of the thermal network model.The equivalent modeling of each heat transfer component of the motor was carried out through the region division,so as to establish the whole thermal network model.The temperature rise distribution of the motor during steady operation is obtained by solving the thermal network model.Finally,the influence of air flow was taken into account in the temperature rise prediction method of motor based on the influence of Reynolds number on the flow resistance of each branch of hydraulic network and the convective heat transfer resistance of thermal network.The bidirectional hydraulic-thermal network coupling was realized by an iterative process.The prototype experimental platform was built for temperature rise experiment to verify the accuracy of the bidirectional hydraulic-thermal network coupling.