Developments of Control and Design strategies for Slotless Permanent Magnet Motors using High Energy Density Magnets

作为全球环境保护中的节能策略之一，电动机驱动系统的效率提高在家用电器和工业应用中得到了促进。其中，从有效利用稀土磁体的观点来看，使用最近开发的具有高能量密度的稀土磁体的无槽永磁同步电动机（无槽PMSM）受到了广泛关注。本课题的主要目的是研究高效率无槽永磁同步电机的优化设计和控制策略，在研究过程中取得了如下成果.考虑到绕组电感值对设计高效率无槽永磁同步电机的重要性，本文对第一台样机的设计策略进行了改进，提出了新的优化设计策略。根据三维有限元分析（3D-FEM）的优化设计结果，我们制作了第二个原型，并对驱动性能进行了实验评估。结果证实，第二个原型与第一个原型相比，可以实现25%的载波损耗降低.通过三维有限元分析，我们确定了这样一个事实，即绕组电感的减少和绕组电阻的增加，随着频率的增加是由于涡流损耗的表面上的Ne-Fe-B永磁体。在此基础上，提出了一种在无槽永磁同步电机设计阶段定量预测载波损耗的方法，并通过第二台样机的实验验证了该方法的有效性。

As one of strategies for saving energy in global environmental conservation, the efficiency improvements of electric motor drive systems have been promoted in home appliances and industrial applications. Among them, Slotless Permanent Magnet Synchronous Motor (slotless PMSM) using recently developed rare-earth magnets with high energy density have been received much attention from a standpoint of effective use of rare-earth magnets. An aim of this project was to develop the optimum design and control strategies for high efficiency slotless PMSM and during research period we had made achievements as follows.1. Considering that winding inductance value is important for designing high efficiency slotless PMSM, we proposed the new optimum design strategy modifying the design strategy of the first prototype. We made the second prototype according to the result of the optimum design using three-dimensional Finite Element Analysis (3D-FEM) and experimentally evaluated the drive performances. As a result, it was confirmed that the second prototype could realize the decrease in carrier loss by 25% compared to the first prototype.2. By using 3D-FEA, we identified the fact that the decrease in the winding inductance and the increase in the winding resistance for an increase in frequency are due to the eddy current loss on the surface of Ne-Fe-B permanent magnets. Based on the above investigation, we proposed a method for the quantitative prediction of the carrier loss at the design stage of slotless PMSM and confirmed the effectiveness of the proposed method by the experiments using the second prototype.