应用于城轨交通大功率直线感应电机牵引系统基础理论和关键技术研究

Linear induction machine(LIM) used in urban railway transportation is of power superiority and high efficiency, while the electromagnetic design and control strategy are difficult. The magnetic circuit breaking, eddy current, large air gap and pulse width modulation lead to the complexity of equivalent circuit, obvious variation of parameters, difficulty of control and low operation efficiency. Conventional approaches are devoted by the suppose of sinusoidal excitation and exponential decay of mutual inductance. Therefore, the research results differ greatly from actual operating performances. This proposal proposes the method of field-circuit coupling. With adequate consideration on the influence of structure, T-model equivalent circuits under sinusoidal and non-sinusoidal excitations can be derived, respectively. Moreover, the change trend of mutual inductance and secondary resistance are investigated. The influence of harmonics on iron loss and torque is analyzed comprehensively. Besides, a method of electromagnetic design under non-sinusoidal excitation is applied. Furthermore, one novel equivalent d-q model is deduced, as well as relative novel field-oriented and parameter identification methods. On the base of new dynamic models,the magnitude and angle of flux are calculated accurately to improve the control accuracy of drive performance. Considering the iron loss and the change of inductance parameters, rapid convergence efficiency optimization strategies are established to improve the efficiency on different operating conditions. Theoretical investigation that combines traction system with simulation modeling is carefully made. The influence of external disturbance and the change of internal parameters on the LIM electromagnetic and drive traits are analyzed deeply, and the dynamic characteristics of non-sinusoidal excitation motor are acquired. Relevant achievements are of extreme importance, and will provide great theoretical support for the development of LIM traction system.

城轨交通直线感应电机动力强劲，功率发挥充分，对电磁设计和控制策略要求很高。因磁路开断、涡流、大气隙、脉宽调制等影响，电机存在等效模型难、参数变化大、控制难度高、运行效率低等问题。传统方法以正弦激励源和假设互感呈指数衰减为前提，研究结果难准确反应电机实际运行特性。本申请拟用场路结合法，充分考虑电机结构影响，先后推导正弦和非正弦激励源下T型等效电路。研究互感、次级电阻等变化规律，分析谐波对铁耗、力矩等指标影响，掌握非正弦激励源下电磁设计方法。进一步推导新型dq轴等效模型，研究磁场定向和参数辨识新方法，准确计算磁链幅值和角度，提高牵引性能。考虑铁损和电感变化，建立快速收敛效率优化策略，提高不同工况下电机工作效率。研究牵引系统联合仿真建模理论，分析外部干扰和内部参数变化对电机电磁和驱动特性影响，准确掌握非正弦激励下电机动态特性。相关成果将为直线牵引系统提供理论支撑，具有重要研究意义。

城轨交通直线感应电机（LIM）因受磁路开断、初次级宽度不等、大气隙等影响，存在参数耦合严重且变化剧烈、等效模型复杂、控制难度大、运行效率低等问题。为此，本项目从LIM物理模型出发，采用场路结合法，分别推导了LIM正弦与非正弦激励下的等效T型电路，提炼出LIM互感、次级电阻等关键参数变化趋势和稳态特性分析方法，并总结了LIM电磁优化设计方法。.基于等效T型电路，本项目推导了新型LIM d-q轴等效电路，大大降低LIM动态控制的复杂度。基于此d-q轴等效电路，本课题实现了LIM次级磁场定向控制，解决了传统控制方法中存在的推力衰减问题，提升了LIM动态响应速度。.在次级磁场定向控制基础上，本项目详细分析了LIM铜耗、铁耗，逆变器导通、开关损耗，建立了LIM驱动系统损耗模型，推导了不同运行工况下的最优磁链水平，显著降低了LIM驱动系统各部分损耗，有效提升了其运行效率。该方法收敛速度快、计算量小，并可直接应用于其它感应电机驱动系统。.为降低LIM运行过程中参数变化对控制性能的影响，本项目提出了一种含约束问题的模型预测控制方法，不仅充分考虑了参数变化信息，还将电压、电流约束包含进来。此方法可快速处理含电压、电流约束条件的求解过程，有效降低LIM输出推力波动，降低变频器开关频率和损耗。.此外，本项目还提出了一种基于扩张状态观测器的无速度传感器控制方法，将LIM电磁模型与机械模型结合起来，提炼出新的LIM速度控制器设计方法。该算法可同时观测LIM运行速度与负载，有效提升了LIM速度观测精度与速度跟踪性能，增强了对负载扰动变化的抑制能力。.基于相关研究，本项目共发表19篇SCI期刊文章、26篇会议文章，其中2篇获会议“最佳论文奖”；获授权专利11项，受理专利39项。相关研究成果均为世界前沿技术，将为城轨交通LIM牵引系统提供有力的理论与实践支撑，创造可观的社会经济价值。