密级：内部高速电主轴永磁同步电机永
磁体涡流损耗计算研究
The calculation and analysis of
high-speed spindle permanent magnet motor eddy current losses in the permanent magnet
学院：电气工程学院
专业班级：电气工程及其自动化0903班
学号：
学生姓名：
指导教师：（副教授）
2013 年 6 月
摘要
永磁同步电机是由永磁体建立励磁磁场的同步电机，电机结构较为简单，降低了加工和装配费用，提高了电机运行的可靠性；又因无需励磁电流，省去了励磁损耗，提高了电机的效率和功率密度。当外磁场发生变化时，永磁体就会产生涡流导致发热。因此，很有必要对转子永磁体内的涡流进行计算和分析，并采取相应的解决办法。
本文主要运用了有限元软件对高速电主轴永磁电机永磁体的涡流损耗进行分析，以得到永磁体涡流损耗的大小和分布规律，并研究永磁体涡流损耗的影响因素，从而为减小永磁体涡流损耗提供依据。
首先建立高速电主轴永磁电机有限元模型，对模型进行激励源加载和剖分，为涡流损耗的分析奠定基础；然后采用上述模型，计算得到永磁体内涡流损耗的大小和分布；分析正弦波供电和变频器供电下永磁体涡流损耗的特点；最后着重研究不同极槽数、转子磁路结构对永磁体涡流损耗的影响，提出减小涡流损耗的措施，为提高电机性能奠定基础。
针对永磁同步电机自身的特点，通过二维电磁场有限元方法分别求解了空载时和负载时电机永磁体内的涡流。采用了瞬态分析，根据瞬态计算出的数据绘出了涡流损耗波形，并得出永磁体内的涡流损耗分布图。最后通过分析波形得出了影响永磁体内涡流的因素以及应采取的措施。
关键词：永磁同步电机；永磁体；涡流损耗；有限元法
I
Abstract
Because of the magnetic field which is built by permanent magnet, permanent magnet synchronous motor (PMSM) has simplified structure and low cost for its machining and installation. Besides, the operational reliability has also been improved. Benefiting from the absence of the exciting current and the excitation loss, the efficiency and the power density have increased.. The eddy current induced in permanent magnet often lead to heat when the external magnetic field is time-varying. So it is necessary to calculate and analyze the eddy current in rotor and to find solutions.
The paper mainly uses the finite element analysis software to analyze high-speed spindle permanent magnet motor eddy current losses in the permanent magnet , so that to get the value and distribution of it. The same time it can study the factors of eddy current loss in the permanent magnet , so as to provide the basis for reducing the eddy current loss.
Firstly, finite element model of the high-speed spindle permanent magnet motor is founded , and the model would be load the excitation source and split , all are laying the foundation for the analysis of eddy current loss ; Then using the above model ,to calculate the value and distribution of eddy current loss in the permanent magnet; characteristics of eddy current loss the permanent magnet under the sine wave power and inverter power is analyzed later; finally focusing on different poles number of slots, the structure of rotor magnetic circuit affect the eddy current loss in the permanent magnet , and take the measures to reduce eddy current loss , to lay the foundation for improving motor performance.
Based on the actual structure of disc type permanent magnet synchronous machines, the magnet field of the machine and the eddy current in the rotor are solved by two-dimensional finite element method (FEM). The calculation is carried out under the condition of load and no-load, respectively. It includes the eddy current caused by the teeth of the stator and the different eddy currents under different running speed conditions. After solution, the magnetic vector potential waveforms
II
