大型直驱风力发电用双定子永磁无刷电机的结构创新和基础理论研究

Double-stator permanent magnet (PM) brushless machines can effectively improve the power density and power to magnet consumption ratio, and therefore, they have great potential in direct drive wind power generation. However, their research is far away from mature, compared with single-stator machines. This project focuses on finding new topologies and building fundamental theory of double-stator PM machines for wind power application..Regarding topology innovation, a new winding layout design method is firstly proposed, which considers both inner and outer stator windings together in the same phasor diagram. By using this method, some new winding layouts and pole/slot combinations are created for double-stator machine, based on the well-known single-stator windings. On the rotor side, a consequent pole structure is introduced to double-stator machine to save magnet consumption. In addition, a new method is proposed to reduce the torque ripple, which shifts the relative circumferential positions of magnet poles on the inner and outer sides of rotor. Furthermore, a new axial layout is proposed which has longer outer stator and shorter inner stator to further improve the power density..Another main focus is to create accurate analytical model of double-stator PM machines, which provides an important tool and better understanding. An accurate analytical field model is developed based on subdomain method, which has been proved very effective and accurate in single-stator machines. Then, the analytical models of basic electromagnetic performance, parasitic force, torque ripple, loss and demagnetisation are created. The developed models will be validated by experimental results..By using the developed analytical models, the influence of key design parameters on both electromagnetic performance and parasitic effects is investigated in depth for both conventional and new machine topologies. Both conventional and new topology machines are optimised and compared. Two down-scaled prototypes of typical new topologies are built and tested. This project will provide theoretical guidance of double-stator PM machine and strengthen Chinese intellectual properties in the field of double-stator PM wind power generators.

双定子永磁无刷电机可以有效提高功率密度和永磁体利用效率，在直驱风力发电领域潜力巨大，然而研究水准与单定子电机有相当差距。本课题研究直驱风力发电用双定子永磁电机的结构创新和基础理论。首先建立内外定子统一设计的创新绕组设计方法。利用此法，在单定子绕组设计基础上，研究发明双定子永磁电机的创新绕组和极槽配合。在转子侧，用软磁材料替代半数永磁体的交替极转子结构（Consequent pole），进一步提高永磁体利用效率，采用转子内外永磁磁极周向错位的方法抑制转矩波动。在轴向上，提出外定子长/内定子短的结构，进一步提高功率密度。采用子域建模方法，建立准确的双定子永磁无刷电机的电磁场解析模型，并依此建立基本电磁性能、寄生力、转矩波动、寄生损耗和退磁等解析模型。深入研究电机设计参数对电机性能和寄生负效应的影响。本课题将会为双定子永磁电机的开发应用奠定理论基础，并完善我国双定子永磁风力发电机知识产权库。

风电作为清洁能源具有良好的发展前景，拥有高转矩密度和高可靠性的风力发电机是未来主要发展趋势。本项目提出了两类新型永磁电机，即双定子永磁无刷电机和双电枢永磁电机，前者具有内外两个定子，后者具有定子电枢绕组和转子电枢绕组，充分利用了转子内部空间，均可有效提高电机转矩密度。.本课题研究了直驱风力发电用双定子永磁电机的结构创新和基础理论。首先建立内外定子统一设计的创新绕组设计方法。利用此法，在单定子绕组设计基础上，研究发明双定子永磁电机的创新绕组和极槽配合。在转子侧，用软磁材料替代半数永磁体的交替极转子结构，进一步提高永磁体利用效率，采用转子内外永磁磁极周向错位的方法抑制转矩波动。在轴向上，提出外定子长/内定子短的结构，进一步提高功率密度。采用子域建模方法，建立准确的双定子永磁无刷电机的电磁场解析模型，并依此建立基本电磁性能、寄生力、转矩波动、寄生损耗和退磁的解析模型等。深入研究电机设计参数对电机性能和寄生负效应的影响。.本课题还研究了新型双电枢永磁电机的工作机理与结构创新，提出不同定转子极数配合、励磁方式、定子结构和绕组结构的多种新型双电枢磁通切换电机。研究电机定转子相数和极数的关系，建立系统的定转子极数配合和绕组设计理论；建立电机的数学模型，全面比较新型双电枢磁通切换电机与传统磁通切换的性能，结果发现前者相比后者转矩密度提高46%，且双电枢磁通切换电机具有更好的容错性能，即使一套绕组发生故障，另一套绕组也可正常工作。.本课题为双定子永磁电机和双电枢永磁电机的优化设计提供理论基础，促进了其在风力发电领域以及航空航天领域的应用。.