非对称初级永磁直线电机牵引系统运行机理与控制方法研究

对于城市轨道交通直线电机牵引系统而言，直线电机在列车运行过程中气隙难以保持恒定。气隙变化导致反电动势不平衡，从而使得采用群控模式（车控模式或架控模式）的初级永磁直线电机牵引系统出现负载电流不平衡和环流等问题，进而增加牵引系统运行能耗和威胁牵引设备安全。鉴于不宜采用群控模式，为了避免采用设备占用空间最大、自身质量最重、运行能耗最多、初期采购成本和后期维护成本均最高的轴控模式，本项目突破现有牵引系统对称结构的思维定式，在综合考虑初级永磁直线电机牵引系统固有特性的基础上，创新性地提出融合车控模式与轴控模式特点的非对称初级永磁直线电机牵引系统。本项目拟对城市轨道交通非对称初级永磁直线电机牵引系统的运行机理、设计方案和控制方法等基本科学问题进行深入的理论分析和实验研究，建立较为完整的系统分析理论与设计方法，为未来永磁直线电机牵引系统在城市轨道交通领域的成功应用奠定坚实的理论基础和技术基础。

In the primary permanent-magnet linear motor (PPMLM) traction system for urban rail transit, the air-gap width of the PPMLM cannot keep unchanged during the operation of the train. The variation of the air-gap width will result in unbalanced back-electromotive-forces. As a result, unbalanced load currents and circular currents will appear in the PPMLM traction system using a group control mode (car control mode or bogie control mode). Additionally, the operation energy consumption will be increased while the safety level of the traction equipment will be reduced. Obviously, the group control mode is not suitable for the PPMLM traction system. According to the current technology, the axis control mode is the inevitable choice for the PPMLM traction system. However, the axis control mode has several significant disadvantages, such as the biggest equipment space, the heaviest equipment weight, the most operation energy consumption, the highest initial purchase cost and the highest late maintenance cost. To avoid using axis control mode, a non-symmetric PPMLM traction system is proposed for urban rail transit in this project, which breaks the traditional symmetric control structure of the traction system and considers the individual features of the PPMLM traction system. Besides, the non-symmetric PPMLM traction system combines the features of car control mode and axis control mode. For the non-symmetric PPMLM traction system, there are some key scientific problems, such as operation principles, design proposals, control methods and so on. They will be investigated by deep theoretical analysis and experimental validation in this project. Also, the complete system analysis theory and the corresponding design method will be developed. The theoretical and technological foundations will be provided for future applications of the PPMLM traction system in the field of urban rail transit.