Temperature Field Analysis Of Permanent Magnet Synchronous Motor Used In Electric Vehicles

The working environment of the permanent magnet motor used in electric cars limits the cooling system design of the motor, making it complicated to calculate its temperature field. But the temperature rise computation in electric motors plays a very important role in estimating the operation reliability and lifespan of the motor, and especially in guiding the motor design. To study the problem, based on heat transfer, fluid mechanics theory and coupling field knowledge, the temperature calculation of the permanent magnet motor used in electric vehicles is analyzed in this paper, so that we can know whether the motor temperature rise meet the requirements.This paper firstly makes equivalent exchanges relatively to parts of the motor model, which simplifies the calculation in the premise of ensuring the accuracy of the temperature rise. The coefficient of heat conductivity of every parts and coefficient of the heat transfer of all boundaries in the motor is analyzed and modified. And the heat source of the motor temperature field-the loss and its distribution in the motor. On above basis we building the heat transfer analysis model and analyzing the temperature field with the finite element software, then calculate the temperature of different locations roughly with multi-slice analysis method, combined with the heat source and its distribution, we can also find the most hot point of the motor of the size most hot find, and then the three dimensional temperature distribution of the motor. At the same time, the influence of changing the cooling water flow to the motor temperature rise was analyzed.According to the coupling principle, the paper analyzes the internal fluid-solid thermal coupled field in the motor then. solve the coupled field Confirm the boundary conditions and obtain the three dimensional temperature distribution results in each part of the simulation, and then Comparing the results with the results of the finite element analysis we will find both results are consistent. The study of this paper makes a great sense to the checking of motor performance and design.