Research On Temperature Rise Of High Speed Permanent Magnet Synchronous Traction Motor

In recent years,great concern has been shown on the application of permanent magnet synchronous motor(PMSM)for high speed rail.China has manufactured and applied the PMSM traction system for high speed rail independently in 2014.The temperature rise has an important influence on motor,especially for the PMSM applied for high speed rail.Overheating may lead to demagnetization and even the loss of magnetism,which is very dangerous for high speed rail.Therefore,the thermal analysis of motor is of great importance.In this paper,thermal circuit method is adopted to calculate the temperature rise of the motor.By setting up a detailed thermal circuit model,the average temperature in both steady state and transient state is available in Simulink.At the same time,this paper analyses the temperature rise of the motor under the rated current,overload current and no-load current.Through the comparison,it can provide reference for the length of run time when the motor is overloaded.In this paper,the computational fluid dynamics(CFD)method is also used to analyse the high speed permanent magnet traction motor.By calculating the motor loss in the electromagnetic field,the corresponding heat source is obtained.In Fluent,the corresponding fluid boundary is set,and then the temperature.rise of the motor is available.In addition,this paper analyses the relationship between different cooling air flow rate and the temperature rise of the motor,which provides a reference for the selection of the wind speed in the design of the cooling system.In order to improve the thermal performance of the motor,this paper designs a zigzag ventilation duct,and determines the optimal parameters of the zigzag structure by means of the coupling of the thermal circuit method and the computational fluid dynamics(CFD)method.A 600kW,4200r/min PMSM prototype with different ventilation structure was established.The temperature results of experiment and calculation are in good agreement,verifying the effectiveness of the analysing method proposed in this paper.Besides the experiment proved that the thermal performance of the motor is improved by 15%with zigzag ventilation ducts.