Research On The Thermal Managemengt Of High Power Density Permanent Magnet Synchronous Motor In Hev

With the progress of society, the growing of the conception of protecting environmental is pushing the rapid development on the electric vehicle, Electric vehicles took a fancy to permanent magnet synchronous motor with its high efficiency, low weight, and nowadays PMSM is widely used in electric car.Permanent magnet synchronous motor will inevitably lead to poor thermal environment, heat production or more problem due to its high power, high speed but small installation space. The high temperature of the motor will cause a hidden dangers in the electric vehicles. In order to avoid such problems, to accurately predict the internal motor under different conditions of temperature distribution to ensure the safe operation of motor stability is very important.This paper is based on a 20kW electric motor cooled permanent magnet synchronous motor firstly to calculate the various parts of the motor loss (heat) with using the combination of theoretical and experimental methods.The steady state temperature field of the permanent magnet synchronous motor is analysed by electromagnetics, heat transfer and fluid mechanics, and interdisciplinar,which is used the equivalent thermal network method to its mathematical model. At the same time, by means of simulation software, this paper provides a finite element method to calculate the motor steady-state and transient simulation temperature with a certain heat source and boundary conditions added on. Then this paper discusses the import and export of the average temperature of cooling water, the water flow rate and the shape of the motor case temperature distribution gradient, also provides the reference for the design optimization.Finally the influence of the temperature to the permanent magnet synchronous motor output efficiency is discussed and a motor test platform is built to test the temperature when the motors run at different operating points by these two mothods. The simulation results are compared, it shows that the calculated temperature field model is reasonable and correct for the temperature field analysis which provides the reference for the designed optimization.