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

提出了高性价比飞轮储能技术的发展方向。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，以及可能在发展中国家使用的不间断电源、分布式储能和离网电力系统等静止应用中。与替代方案相比，飞轮储能的显著优势是它结合了非常高的功率密度和中等到分别高的能量密度。要研究的一种实现低成本飞轮储能系统的方案是使用单个高强度铁磁性钢结构部件，该结构部件既可以作为储能转子，也可以作为适当尺寸的电机/交流发电机的集成转子。正如提案中所概述的，这种方案可以产生一个功能齐全、成本效益高的大功率电能储能库。研究的重点将集中在样机硬件的设计、制造和测试上，以验证这一概念。努力将重点放在这种集成电机/交流发电机的设计上，并设计出适合这一应用的主动磁轴承系统。特别是，提出了一种结合了自感知的主动磁轴承，其中轴承控制绕组也被有效地用于传感。现有的主动磁悬浮轴承由于需要集成独立的专用位置检测设备以及所需的支持硬件和功率而存在复杂性，其结果是这些磁悬浮轴承系统的成本很高，可靠性也受到影响。

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.