车用永磁同步电机的铁耗计算

发布时间：2018-04-09 00:30

本文选题：永磁同步电机　切入点：铁耗计算模型　出处：《上海交通大学》2014年硕士论文

【摘要】：新能源汽车的蓬勃发展促进驱动电机的发展。永磁同步电机作为新能源汽车动力系统的核心部件,其损耗大小直接影响电机的效率和温升,进而影响到汽车的续航里程和正常工作寿命。铁耗在该类电机的损耗中占较大比重,因此准确计算永磁同步电机铁耗是新能源汽车电机设计的关键。电机铁耗的产生机理很复杂,影响因素较多。各国学者们根据理论分析和实测数据提出了许多不同的铁耗算法。本文根据损耗理论借助于商用电磁场有限元分析软件Ansoft进行铁耗计算。首先阐述了铁磁材料损耗(包括磁滞、涡流以及异常损耗)的产生机理。在此基础上介绍了旋转磁密和电机制造工艺等因素对铁耗的影响。介绍了Ansoft内部的铁耗计算方法。比较了三项和两项铁耗模型在拟合磁密损耗曲线时的效果,得到了各项损耗系数。其次介绍了本文所研究的车用永磁同步电机的结构特点、电磁参数以及工作电流的求解方法。在此基础上分析了电机定转子铁耗的来源,通过空间磁动势波形的正弦波分解,推导其高次空间谐波的含量和在转子中感应出的高次时间谐波,为下文分析转子中磁密波动来源提供了依据。给出了有限元法计算永磁体涡流损耗的要点。本文进一步对铁耗计算经常被忽略的因素进行了深入的探索。一方面直接对单一硅钢片进行三维建模,通过计算硅钢片内部涡流直接求解涡流损耗。另一方面,以滤波后的实测电流作为激励,考虑高次谐波电流对电机铁耗的影响,得到了对应的计算铁耗的修正系数。为了快速求得电机在各工况下的铁耗,本文从磁密出发,用两项铁耗模型,依据不同工况下电机铁芯不同部分磁密分布的特点,简化了铁耗计算方法。提出了一种快速铁耗计算方法。该方法与有限元法计算结果比较误差很小。最后,本文分析了定子绕组铜耗和转子机械损耗,并根据实验测试结果得到了它们的计算公式,进一步获得电机运行中的各项损耗大小。在各种工况下,采用理论方法求得定子绕组铜耗和转子机械损耗后,再与理论计算基波铁耗相加得到电机总损耗。该理论计算值与实测值比较存在一定误差。通过考虑高次谐波电流对铁耗的影响,即对铁耗计算值进行修正,修正后的理论计算结果和实测值基本吻合。
[Abstract]:The vigorous development of new energy vehicle promotes the development of drive motor.Permanent magnet synchronous motor (PMSM) is the core component of the power system of new energy vehicle. Its loss directly affects the efficiency and temperature rise of the motor, and then affects the vehicle's range and normal working life.Iron consumption accounts for a large proportion of the loss of this kind of motor, so calculating the iron loss of permanent magnet synchronous motor accurately is the key to the design of new energy automobile motor.The mechanism of iron loss of motor is very complex, and there are many influencing factors.According to the theoretical analysis and measured data, many different iron loss algorithms have been proposed by scholars from various countries.Based on the loss theory, the iron loss is calculated by means of the commercial electromagnetic field finite element analysis software Ansoft.Firstly, the mechanism of ferromagnetic material loss (including hysteresis, eddy current and abnormal loss) is introduced.On this basis, the influence of rotating magnetic density and motor manufacturing technology on iron loss is introduced.The calculation method of iron consumption in Ansoft is introduced.The effects of three and two iron loss models in fitting the magnetic density loss curve are compared and the loss coefficients are obtained.Secondly, the structure characteristics, electromagnetic parameters and working current of the permanent magnet synchronous motor (PMSM) studied in this paper are introduced.On this basis, the source of iron loss of stator and rotor of motor is analyzed, and the content of high order spatial harmonic and the high order time harmonic induced in rotor are deduced by the sine wave decomposition of spatial magnetic EMF waveform.It provides the basis for analyzing the source of magnetic density fluctuation in rotor below.The main points of calculating eddy current loss of permanent magnet by finite element method are given.In this paper, the factors which are often neglected in iron consumption calculation are further explored.On the one hand, the single silicon steel sheet is directly modeled, and the eddy current loss is solved directly by calculating the eddy current inside the silicon steel sheet.On the other hand, the effect of high harmonic current on iron loss of motor is considered, and the corresponding correction coefficient of iron loss is obtained by taking the measured current after filtering as excitation.In order to find out the iron loss of the motor under different working conditions, the calculation method of iron loss is simplified by using two iron loss models and according to the characteristics of magnetic density distribution of different parts of the motor core under different working conditions.A fast calculation method for iron consumption is presented.The error of comparison between this method and the finite element method is very small.Finally, the copper loss of stator winding and the mechanical loss of rotor are analyzed, and their formulas are obtained according to the experimental results.Under various working conditions, the total loss of the motor can be obtained by adding the copper loss of the stator winding and the mechanical loss of the rotor to the theoretical calculation of the fundamental iron loss.There is a certain error between the calculated value of the theory and the measured value.By considering the influence of high harmonic current on iron consumption, the calculated iron loss value is modified, and the theoretical results are in good agreement with the measured value.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U463.6;TM341

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