沈阳工业大学硕士论文电机铁耗的研究

电动机在现代工业中起着重要作用，是耗电量最多的一种电气设备．因此在能源问题日趋严重的今天，降低电机损耗，提高电机系统效率，对节约能源、控制环境污染等方面有着重要的意义．在电机中，铁心损耗作为不变损耗，占了总损耗的较大比重．特别是随着电力电子技术的发展，越来越多的电机采用逆变器进行供电，逆变器输出的谐波分量不仅会在定子铁心产生附加铁耗，同时还会在转子铁心中产生附加损耗．考虑到电机转子散热条件较为恶劣，这将会对电机的工作寿命造成影响．因此，有必要对变频异步电机的铁心损耗进一步分析，以改善工作性能．
本文首先从铁磁材料磁化机理出发，较为详细的分析了铁磁材料的磁滞损耗、涡流损耗以及异常涡流损耗的产生原因和各自的计算方法，推导了非正弦供电下电机铁耗的计算模型．然后，详细而系统的分析了变频异步电机中的时间谐波和空间谐波的产生机理，分别指出了时间谐波和空间谐波对异步电机铁心损耗的影响．接下来，利用Ansoft公司的Maxwell 2D瞬态模块建立了异步电动机的有限元模型，并且采用其自带的电路编辑器Schematic Capture设计了异步电机逆变器控制电路，构建了一个完整的变频控制系统场路耦合仿真模型．同时采用Rmxprt软件对电机进行磁路分析，计算所需电机参数作为有限元分析的输入数据．通过对仿真模型进行瞬态有限元分析，研究了调制比、开关频率等逆变器参数对电机铁心涡流损耗的影响．
另外，针对转子铁心损耗计算难以得到实验验证的现状，本文提出了一种转子铁损测试的实验方案．该方法可验证电机转子铁耗的计算，从而为提高电机设计精度和工程应用提供指导，具有较好的现实意义．

Research of Iron Losses in Induction Motor Fed by Inverter
Abstract
As is well known, induction motor plays an important role in modern industry, and is a kind of electric equipments which have the most power consumption. Therefore, it is important to improve the efficiency of induction motor not only from the viewpoint of energy saving, but also from the broad perspective of environmental. In the motors, iron losses account for a larger proportion of the total losses. In particular, with the power electronics technology development, more and more motors are supplied by power inverter. And the output harmonic component of the inverter will not only generate additional losses in the stator core, but also in the rotor core. Taking into account the cooling condition of the rotor is bad, this will have an effect on working life of the motor. Therefore, it is necessary for the iron losses of the induction motor fed by inverter to analyze further, in order to improve the working performance.
Based on the magnetization mechanism of the ferromagnetic material, the work deeply analyzes the generated reason and calculated methods of the losses in ferromagnetic material, including hysteresis losses, eddy losses and anomalous losses. The iron loss model of the motor under non-sinusoidal supply is also deduced. Furthermore, the generation mechanics of time and space harmonics in the inverter-fed induction motor is analyzed in details. The influences of both types of harmonics on the iron losses of induction motor are described. Next, the finite element model of induction motor is established by using Maxwell 2D transient module, and the inverter control circuit is also designed by its own circuit design editor. Consequently, a complete field-circuit coupled simulation model of inverter control system is presented. At the same time, Rmxprt software is adopted to analyze the magnetic circuit of the motor, in order to use the calculated results of the required electrical parameters as finite element analysis of input data. Through transient finite element analysis to the simulation model, the effect of inverter parameters, such as amplitude modulation ratio and switching frequency, on eddy current losses in induction are studied.
In addition, because it is difficult to measure the rotor iron losses, there is no appropriate experimental vertification method for the calculation method. An experimental verification method which can verify the calculation method is presented, so as to improve the accuracy of the electrical design and to provide guidance of the engineering.

Key Words：Ferromagnetic Material，Iron losses computation, Harmonic analysis，Rotor losses

目    录
摘    要    I
Abstract    II
第一章 绪论    1
1.1 引言    1
1.2 电机铁耗的研究现状和意义    2
1.3 本文研究的主要内容    4
第二章 铁磁材料及其损耗    6
2.1 铁磁材料    6
2.1.1 磁化现象    7
2.1.2 磁滞现象    8
2.1.3 居里温度与磁致伸缩    9
2.2 铁磁材料中的铁耗    9
2.2.1 磁滞损耗    10
2.2.2 涡流损耗    10
2.2.3 异常涡流损耗    13
2.3 电机铁耗计算模型    14
2.4 本章小结    15
第三章 变频异步电机中谐波问题的研究    16
3.1 异步电机的谐波分析    16
3.1.1 异步电机气隙磁场中的空间谐波    16
3.1.2 异步电机气隙磁场中的时间谐波    19
3.2 变频异步电机中的时间与空间谐波    22
3.3 谐波对异步电机铁耗的影响    24
3.3.1 时间谐波对异步电机铁耗的影响    24
3.3.2 空间谐波对异步电机铁耗的影响    25
3.4 本章小结    26
第四章 变频异步电机涡流损耗的仿真研究    27
4.1 Ansoft EM软件简介    27
4.1.1 Maxwell软件包简介    27
4.1.2 Rmxprt软件包简介    28
4.2 变频异步电机仿真模型的建立    28
4.2.1 变频异步电机的有限元模型    28
4.2.2 绕组外部控制电路    30
4.2.3 变频异步电机模型的网格剖分    33
4.3 基于时步有限元的铁耗计算方法    34
4.3.1 时步有限元理论    34
4.3.2 计算方法    37
4.4 逆变器参数对电机涡流损耗的影响    37
4.4.1 调制比对涡流损耗的影响    38
4.4.1 开关频率对涡流损耗的影响    39
4.5 本章小结    40
第五章 变频异步电机转子损耗实验研究    41
5.1 实验原理    41
5.2 实验方法    42
5.3 本章小结    46
第六章 结论    47
参考文献    48
在学研究成果    51
致    谢    52