【作者】 杨超南；

【导师】 张奕黄；

【作者基本信息】 北京交通大学 ， 电气工程及其自动化， 2012， 硕士

【摘要】 电动汽车用永磁电机的工作环境限制了电机的冷却系统设计,使得电机温度场的计算变得复杂,而电机的温升计算是电机的运行可靠性及寿命估计的重要依据,在指导电机设计时显得尤为重要。为研究这一问题,基于传热学、流体力学理论及耦合场相关知识,本文中对电动汽车用永磁电机的温度计算进行了分析计算,以确定电机温升是否满足要求。本文首先对电机部分模型进行了相关等效,在不影响温升结果精度的前提下简化了计算。分析了电机内的各导热体的导热系数和各边界面的散热系数并予以修正,同时研究了电机内温度场的热源——电机的损耗及其分布。在此基础上建立了电机传热学分析模型并运用有限元软件对电机的温度场进行分析,并利用多截面分析方法,推出电机各位置的大致温度,结合热源大小及其分布找出电机的最热点,进而分析电机的三维温度分布。同时,分析了冷却水流量改变对电机温升的影响。根据耦合基本原理,本文同时对电机内部的流固热耦合场进行了计算。将电机水套内的冷却流体场和电机温度场进行耦合求解,确定边界条件,并得到电机各部分的三维温度分布的仿真结果,然后将得到的结果和有限元分析结果进行对比,两者结果基本相符,对于电机的性能校核及设计分析具有一定的工程应用价值。更多还原

【Abstract】 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.更多还原