新型定子聚磁式永磁记忆电机研究

Variable flux memory machines (VFMMs) are widely recognized as a breakthrough of conventional permanent magnet (PM) machines, which are genuine adjustable-flux PM machines. VFMMs utilize either stator armature windings or additional DC coils to energize remagnetizing/demagnetizing current pulses to vary the magnetization state (MS) of low coercive force (LCF) magnets, and the corresponding MS can be memorized. Therefore, the flexible air-gap flux control can be achieved with negligible excitation loss. As a new concept of PM machine, VFMM is promising for many industrial applications such as automotive, wind power generation and domestic appliances, etc..Based on the winding pattern supplying current pulse, the existing VFMMs can be categorized into AC- and DC-magnetized types. The former type has the simple structure. However, the online magnetization control is relatively sophiscated due to the integration of power and magnetization functions in the armature winding; on the other hand, the latter type can expediently realize online magnetization control. Nevertheless, the relatively complicated stator structure and low torque density are the major concerns for those DC-magnetized VFMMs..This project innovatively proposes a novel stator flux-concentrating permanent magnet memory machine (SFCPM-MM), which not only inherits the advantages of simple structure and high reliability in doubly salient reluctance machines, but also benefits from easy magnetization control in DC-magnetized VFMM. Meanwhile, the stator PM flux-concentration is expected to resolve the demerits of low torque density in conventional DC-magnetized VFMMs. The main research contents include: (1) explore the feasible advanced topologies featuring high efficiency and wide-speed-range, study the electro-mechanical energy conversion mechanism by analytical model; (2) research the flux regulation physics of this type of machine, investigate the variation pattern of PM magnetization states under different operating conditions; (3) summarize the rapid calculation technique for machine parameters and electromagnetic characteristics, generalize a multi-objective electromagnetic design methodology; (4) explore the PM synchronous and doubly salient wound field dual mode operations, research the coordinated strategy between dual mode operation, online flux regulation and drive control in order to achieve high efficiency and wide-speed-range operation. .This project aims to not only enrich the connotation of VFMM, but also lay a solid foundation for the engineering application of the proposed SFCPM-MM in the wide-speed-range industry sectors.

记忆电机是对传统永磁电机的突破，它通过改变永磁磁化水平来调控气隙磁通，几乎无励磁损耗，因而被称为真正意义上的宽调速永磁电机。本项目创造性地提出了一种定子聚磁式永磁记忆电机，既继承了双凸极磁阻电机结构简单和高可靠性的优势，又能发挥直流调磁记忆电机调磁控制简单的特点，且具有定子聚磁能力，有望解决传统记忆电机的转矩密度低的问题。主要研究内容包括：（1）探索该类电机适于高效宽调速的先进拓扑结构，基于解析模型深入分析其机电能量转换原理；（2）研究该类电机的调磁机理，掌握不同运行工况下永磁磁化特性的变化规律；（3）总结此类电机的参数和性能的快速计算技术，掌握一套多目标电磁设计方法；（4）探寻该电机永磁同步和双凸极电励磁双模式运行，研究双模式与调磁驱动协调控制策略，以实现系统高效宽调速运行。本项目的开展不仅可以丰富记忆电机的内涵和形式，也将为该类电机在宽调速领域的工程应用奠定理论与技术基础。

本项目按研究计划进行实施，达到了预期的研究目标。通过对新型直流调磁型记忆电机理论及其在线调磁技术的深入研究，将双凸极结构与记忆电机概念巧妙地相结合，提出了多种适合于电动汽车、高速机床和飞轮储能等宽调速领域的新型直流调磁型记忆电机。根据不同永磁位置，可以分为定子表嵌式/内置式（聚磁型）永磁记忆电机，旨在实现反电动势正弦及调磁控制简单，解决传统直流调磁型记忆电机定子结构比较复杂的问题，进一步提高转矩密度，满足宽速高效运行、可靠性高和低成本的要求。项目执行期间，负责人以第一作者在国内外主流学术期刊和国际学术会议上发表了多篇学术论文，获授权专利9件，也斩获了国际顶级会议最佳论文奖等重要奖项。研究成果引起了国内某车企的关注，已与我校开展科研合作，共同开发适用于电动汽车的记忆电机驱动系统。