Motor/Alternator and Magnetic Bearing Design for Advanced Flywheel Energy Storage Systems

提出了发展具有成本效益的飞轮储能技术。飞轮储能是一项重要的候选技术，可应用于电动汽车，特别是混合动力汽车，以及包括不间断电源、分布式储能和发展中国家潜在的离网电力系统在内的固定应用。飞轮储能相对于其他替代方案的显著优势是其非常高的功率密度以及中等到分别高能量密度的组合。研究一种实现低成本飞轮储能系统的方案，即使用单个高强度铁磁钢结构构件，既可以作为储能转子，又可以作为适当尺寸的电机/交流发电机的集成转子。正如提案中概述的那样，这样的方案可以产生功能良好且成本有效的高功率电能存储库。研究的主要重点将放在原型硬件的设计、制造和测试上，以证明这一概念。这项工作将集中在这种集成电机/交流发电机的设计上，以及为这种应用设计合适的主动磁轴承系统。特别地，提出了一种结合自传感的主动磁轴承，其中轴承控制绕组也有效地用于传感。由于需要集成单独的专用位置传感设备，以及所需的支持硬件和电源，现有的主动磁轴承存在复杂性。结果是这些磁轴承系统的高成本和可靠性受损。

The development of cost effective flywheel energy storage technology isproposed. Flywheel energy storage is an important candidate technology for applicationin electric drive vehicles, especially in hybrid electric vehicles, and in stationaryapplications including uninterruptible power supplies, distributed energy storage, and off-grid power systems as potentially used in the developing world. The distinguishingadvantage of flywheel energy storage with respect to the alternatives is its combinationof very high power density along with its moderate to respectively high energy density.One scheme for realizing a low-cost flywheel energy storage system, to be investigated, relieson the use of a single high-strength ferromagnetic steel structural member that suffices as both the energy storage rotor and the integrated rotor of an appropriately dimensionedmotor/alternator. As outlined in the proposal, such a scheme can result in a functionaland cost effective high-power electrical energy storage reservoir. The main focus of the researchwill be on the design, fabrication, and test of prototype hardware to prove out this concept.The effort will focus on the design of this integrated motor/alternator, and on the design of a suitable active magnetic bearing system for this application. In particular, an active magnetic bearing that incorporates self-sensing where the bearing control windings are also effectively used for sensingis proposed. Existing active magnetic bearings suffer from complexity due to the need to incorporateseparate dedicated position sensing devices, along with the required support hardware and power.A consequence is in high cost and compromised reliability of these magnetic bearing systems.