磁齿轮复合电机内转子涡流损耗分析与设计

发布时间：2018-09-19 15:22

【摘要】：目前,为满足新能源领域对低速大转矩电机的要求,一些学者将磁齿轮与永磁电机相结合提出一种新型“伪”直驱复合式电机。该复合式电机采用共轴式结构,通过调磁环来调制内转子永磁体产生的磁场,与外转子永磁体产生的磁场相互耦合,从而将内置式永磁电机转矩放大。为获得高转矩密度,磁齿轮复合式电机采用大量稀土永磁体,高速运行状态下永磁体中的涡流损耗较大,易使永磁体因电机内部温度过高发生不可逆退磁。因此,为提高磁齿轮复合式电机的可靠性,避免永磁体高温退磁,对复合式电机的永磁体损耗特性以及如何有效降低涡流损耗的研究具有重要的实际价值。本文对复合式电机的调制原理进行论述与验证,分析了复合式电机的转矩和涡流损耗特性,研究并总结产生恒定转矩和涡流损耗的空间谐波组成成分,并提出一种新型串联spoke内转子复合式电机结构。该新型结构考虑永磁体涡流损耗以及磁齿轮电机转矩与内置永磁电机转矩的平衡问题,使得新型串联spoke结构电机与传统表贴式电机相比具有输出转矩几乎不变、涡流损耗降低明显的优势。本文基于以上问题开展以下几个方面的研究:1.采用解析法对磁齿轮复合电机的调制原理进行分析与论述,并通过二维有限元仿真对复合式电机的调制原理进行验证。2.对磁齿轮复合式电机的调制作用原理分析,总结出产生转矩、涡流损耗的谐波成分。对内外转子永磁体涡流损耗进行计算与对比,证明涡流损耗主要集中在内转子永磁体上,为下文通过改变内转子永磁体结构减小涡流损耗、提高电机效率提供理论依据。3.从内转子磁路耦合与非耦合结构以及不同调制比两个角度出发,分别分析内转子永磁体磁路耦合与非耦合以及不同调制比对磁齿轮复合式电机转矩和涡流损耗特性的影响。基于以上两个角度电机特性的分析,进一步验证内转子永磁体结构对电机转矩和涡流损耗特性的影响。4.基于磁齿轮复合电机稀土材料用量一定的条件,创新性的提出内转子永磁体串联spoke结构,并用有限元分析软件Ansoft对所提出结构进行了二维仿真验证,且与已存在的表贴式结构样机进行对比验证,证明新型串联spoke结构在降低永磁体涡流损耗方面的优势。
[Abstract]:At present, in order to meet the requirements of low-speed and high-torque motors in the field of new energy, some scholars have proposed a new type of "pseudo-direct-drive compound motor" by combining magnetic gear with permanent magnet motor. The compound motor adopts coaxial structure and modulates the magnetic field generated by the permanent magnet of the inner rotor by adjusting the magnetic ring, which is coupled with the magnetic field generated by the permanent magnet of the outer rotor, thus amplifying the torque of the built-in permanent magnet motor. In order to obtain high torque density, a large number of rare earth permanent magnets are used in the magnetic gear composite motor. The eddy current loss in the permanent magnet under high speed operation is large, which makes the permanent magnet irreversibly demagnetization due to the excessive internal temperature of the motor. Therefore, in order to improve the reliability of magnetic gear composite motor and avoid high temperature demagnetization of permanent magnet, it is of great practical value to study the characteristics of permanent magnet loss of composite motor and how to reduce eddy current loss effectively. In this paper, the modulation principle of compound motor is discussed and verified, and the characteristics of torque and eddy current loss of composite motor are analyzed, and the spatial harmonic components that produce constant torque and eddy current loss are studied and summarized. A new structure of series spoke inner rotor composite motor is proposed. The new structure takes into account the eddy current loss of permanent magnet and the balance between the torque of the magnetic gear motor and the built-in permanent magnet motor, which makes the output torque of the new series spoke motor almost unchanged compared with the traditional surface motor. The eddy current loss reduces the obvious advantage. Based on the above questions, this paper studies the following aspects: 1. The modulation principle of magnetic gear composite motor is analyzed and discussed by analytic method, and the modulation principle of composite motor is verified by two-dimensional finite element simulation. By analyzing the modulation principle of magnetic gear composite motor, the harmonic components of torque and eddy current loss are summarized. The eddy current loss of the inner and outer rotor permanent magnet is calculated and compared. It is proved that the eddy current loss is mainly concentrated on the inner rotor permanent magnet, which provides a theoretical basis for reducing the eddy current loss and improving the motor efficiency by changing the structure of the inner rotor permanent magnet. Based on the coupling and uncoupling structure of inner rotor magnetic circuit and different modulation ratio, the effects of magnetic circuit coupling and non-coupling of inner rotor permanent magnet and different modulation ratio on torque and eddy current loss characteristics of magnetic gear composite motor are analyzed respectively. Based on the analysis of the characteristics of the motor at the above two angles, the influence of the permanent magnet structure of the inner rotor on the torque and eddy current loss characteristics of the motor is further verified. Based on a certain amount of rare earth material of magnetic gear composite motor, a series spoke structure of inner rotor permanent magnet is innovatively proposed, and the structure is verified by two-dimensional simulation with finite element analysis software Ansoft. Compared with the existing surface structure prototype, it is proved that the new series spoke structure can reduce the eddy current loss of permanent magnet.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM35

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