新型混合励磁变磁通直线电机工作机理及关键技术研究

The operation principle and design method of a kind of novel hybrid excitation variable flux linear motor(HEVFLM) will be thoroughly investigated. The innovation lies in the structure of opening winding which is an integrated winding to supply with the armature current and excitation current together, and the permanent magnets are only inserted in the primary slot. It exhibits many advantages such as low cost, wide speed range, low no-load normal force and so on, which is suitable for equipments such as precise digital machine tools, wave energy generator, logistics conveyors, etc..Several novel topologies of flat single-side, flat double side and modular structures are presented with different slot/pole number combinations, winding structure and different permanent magnet materials. Their operation principles and the impact factor of end effects are analyzed. By investigating the influence of motor structure on thrust force and normal force, the optimization design is completed with the optimal objective of high thrust force density and low thrust ripple. After the coupled-field analysis model of magnetic field and temperature field is established, the eddy current loss, temperature rise and operating point of permanent magnets are calculated, and then the optimal method of structure can be proposed to avoid irreversible demagnetization. With the whole simulation model including motor and control is established,the dynamic end effect and the self-protection of fault tolerant performance at high speed due to failure of inverter is investigated. After that, the high fault-tolerant, hybrid excitation control method with regulation of thrust force ripple is proposed. Finally, the general theory of this kind of motor design is established. Two optimised motors are made and applied to actual equipments of precise digital machine tools and wave energy generator.

全面研究一类新型混合励磁变磁通直线电机（HEVFLM）工作机理与设计方法，其结构创新在于初级开绕组为集成绕组,同时输入电枢电流与励磁电流，永磁体仅位于初极槽中，具有低成本、宽调速和低空载法向力等优点，适用于精密机床、海浪发电与高速物流等设备。.提出不同极槽配合、不同绕组结构与不同永磁材料的平面单边型、平面双边型与模块化等多种新型HEVFLM拓扑结构，分析工作机理及边端效应影响因素；系统研究电机结构对推力与法向力的影响，以高推力密度和小推力波动为优化目标，采用全局优化方法完成优化设计；建立磁场温度场耦合的分析模型，计算不同工况下永磁体涡流损耗、温升与工作点，提出结构优化措施避免出现永磁体失磁；建立电机与驱动控制整体分析模型，分析动态边端效应与高速逆变器故障时自保护容错特性，提出带推力波动补偿的容错混合励磁控制策略，建立该类电机优化设计通用理论；制造2种样机并应用于精密机床与海浪发电机设备。

本项目在国内外现有初级永磁励磁型直线电机研究的基础上，将电励磁与永磁励磁通过并联磁路有机结合，提出了一类混合励磁变磁通直线电机（HEVFLM），包括槽口永磁型、游标型和聚磁式游标型三种拓扑结构及其绕组改进形式，创新性地将励磁绕组与电枢绕组结合成单套集成绕组，在开绕组结构下输入直流偏置型正弦交流电同步输入电励磁电流与电枢电流, 极大地提高了绕组的利用率和电机的推力密度。.研究内容包括建立基于较高精度的磁动势-磁导解析模型、单变量优化与全局优化的优化设计模型与混合励磁仿真模型，分析了有效推力的气隙磁场各次有效谐波、电励磁与永磁励磁对推力的贡献比例，重点对比了励磁绕组分离式与集成式结构下电机的空载特性、推力特性、损耗特性和退磁特性，研究表明采用集成绕组后相同损耗下推力密度可以得到明显提升，在槽口永磁型HEVFLM中提升约88%，游标型及聚磁式游标型HEVFLM中提升约20%。最后，加工制作了三台样机，搭建了实验平台，测试结果验证了理论分析和仿真计算的正确性。研究成果为HEVFLM的开发与应用提供了理论支持。.HEVFLM具有低成本、低法向力的特点，在先进制造、海浪发电等场合中具有很好的应用前景。