夹层电枢的磁场调制型永磁直线发电机解析方法及数学模型研究

Free-piston linear generator system demands excellent comprehensive performance of linear generator. But the relationships among various performance metrics of the generator are complex, so it is difficult to balance and handle them effectively. At the same time, the longitudinal end effects can cause limited application of analytical methods, inaccurate mathematical model and difficult controller design for permanent magnet (PM) linear generator. Combined windings characteristics of flux-modulated machine with that of slotless machine, this project proposes a flux-modulated PM linear generator with sandwiched armature stator. By matching design of sandwiched armature, the generator can achieve outstanding comprehensive performance. First, this project intents to analyze the influences of longitudinal end effects, and then explores revised analytical methods of magnetic field and magnetic circuit model. Based on improved analytical relationships between design parameters and electromagnetic performances, multi-objective optimization of the linear generators are discussed. Further, the researches on electromagnetic parameters analysis under different conditions are carried out, and then design criterions and operation characteristics are summarized. Finally accurate mathematical model canbe acquired and its application scopes canbe widened. The studies on accurate electromagnetic calculations, comprehensive performance optimization, and establishment of non-linear mathematical model for the novel linear generator will refine its design theory, and provide important theoretical supports for excellent control system.

自由活塞式内燃-直线发电机系统要求直线发电机具有良好的综合性能，但电机各个性能参数间存在复杂的制约关系，难以有效地平衡和处理。同时，由于端部效应的影响，永磁直线发电机还存在解析方法精度受限、数学模型不够准确及控制难度高等问题。结合磁场调制型电机与无槽电机的电枢绕组设计特点，本课题提出一种具有夹层电枢的磁场调制型永磁直线发电机，通过对夹层电枢参数的匹配设计可以实现突出的综合性能优势。本申请拟从端部效应分析入手，探索直线发电机的电磁场解析与磁路模型的修正计算方法，建立发电机的电磁关系解析模型，突破其多目标优化设计方法；开展不同工况条件下的电磁参数研究，揭示发电机在设计与运行中的规律性特征，以实现对其数学模型的准确描述和应用拓展研究。通过对新型直线发电机在电磁关系精确计算、综合性能优化及非线性数学模型构建等方面深入探究，完善其精细化设计理论，并为高性能控制器的研发提供理论支撑和依据。

基于自由活塞式内燃机-直线发电系统的应用需求，本项目针对夹层电枢结构的磁场调制型永磁直线发电机在设计及运行中的规律性特征来展开研究。在电磁关系解析模型构建方面，揭示出端部效应对气隙磁场的影响规律，建立端部磁场子域模型，形成计及端部效应的电机磁场修正计算方法。分析获得不同初、次级相对位置的磁场分布特点，采用各个运行点磁力线划分的微元方法构建动态磁网络模型，提升了复杂磁场电机的磁路模型精度。建立主要性能与结构参数之间的关系，采用田口算法和遗传算法完成电机推力密度和效率的多目标优化，并提出基于线圈温升实验的逆向设计方法，提高电机的推力密度和可靠性。揭示出电机定位力的变化规律，提出倒角及圆角型调磁块的方法以减小其定位力；揭示出工况周期内电机电感、磁链等电磁参数的变化规律，建立复合电枢结构永磁直线发电机的非线性动态仿真模型。提出采用非导磁材料的固定绑带和环氧树脂胶整体灌封的方法，完成夹层电枢的磁场调制型永磁直线发电机样机的研制，样机的静态实验测试结果表明，电机的推力随电流变化的线性度好，机电时间常数小，综合性能优势显著且设计灵活性强，在自由活塞式内燃机发电系统具有广阔的应用前景。