A Study on Flywheel Energy Storage System Mounted on Electric Vehicle

飞轮储能系统（FESS）的工作原理是加速飞轮高速旋转，并保持系统中的能量为动能。通过使飞轮减速，能量被转换回来。典型的系统由一个转子组成，转子由真空室内的轴承悬浮以减少摩擦，转子与组合电动机/发电机相连。主动磁轴承（AMBs）是提高总能源效率所必需的。在传统的机械轴承中，粘性阻尼与速度成正比，在高速下，会损失太多的能量。在这种背景下，我们一直专注于在FESS中使用AMB，因为它具有显著的优势，例如高速旋转时的无接触和无摩擦轴承。通常，磁性轴承大多仅用于具有固定环境的系统中。与此相反，我们开发了一种采用磁轴承和万向节机构作为储能系统的飞轮车辆。飞轮动力辅助汽车……很久以前，人们就开始研制飞轮系统（主要是机械的，或带有机械轴承的），并正在进行研究，努力使飞轮系统更小、更轻、更便宜、容量更大。提出的飞轮系统将消除现有电池系统的缺点，如低功率密度、长充电时间、重量大、寿命短和铅污染。飞轮的缺点是能量难以长时间储存。高速旋转意味着要保证爆炸事故的安全。考虑到这一点，选择碳纤维增强聚合物（CFRP）作为飞轮的材料，因为它比钢更轻，但更坚固。在车辆应用中，飞轮也充当陀螺仪体，因为角动量通常与作用在移动车辆上的力具有相似的数量级。这一特性可能对操作特性有害。此外，该特性可用于提高曲线稳定性。相反，这种影响几乎可以完全消除安装飞轮在一个适当的应用一组万向架，角动量是守恒的，而不影响车辆。通过对陀螺效应进行有效补偿的控制器，实现了零偏AMBs支撑飞轮的良好性能。飞轮可旋转高达300Hz，无任何陀螺仪效应。我们将FESS安装在电动汽车上，并设计了电力转换器对能量进行充放电。提出并实现了一种补偿电动汽车转弯时陀螺效应的新算法。本报告描述了机动性和整体能效方面的实验结果，包括线控转向系统的可行性测试、实现输入整形以降低振动和陀螺仪效应、飞轮姿态控制的简单自适应控制方法、能量转换系统的效率测量等室外现场实验结果。少

Flywheel energy storage system (FESS) works by accelerating flywheel to high speed rotation and maintaining the energy in the system as kinetic energy. The energy is converted back by slowing down the flywheel. A typical system consists of a rotor suspended by bearings inside a vacuum chamber to reduce friction, connected to a combined electric motor/generator. Active magnetic bearings (AMBs) are necessary to improve total energy efficiency. In conventional mechanical bearings, viscous damping is directly proportional to speed, and at high speed, too much energy would be lost. From this background, we have been focusing on the use of AMB in FESS due to the significant advantages such as contactless and frictionless bearings at high speed rotation. Usually, magnetic bearings are mostly used only in systems with immovable environment. Here on the contrary, we developed a vehicle with flywheel using magnetic bearing and gimbal mechanism as energy storage system.Flywheel-power assisted car … More s (mostly mechanical, or with mechanical bearings) have been developed since long time ago and in ongoing researchs in effort to make flywheel systems smaller, lighter, cheaper and have greater capacity. Proposed flywheel systems would eliminate the disadvantages of existing battery systems such as low power density, long charge times, heavy weight, short lifetimes, and lead pollution. The weakness is difficulty to store energy for a long time in flywheel. And, high speed rotation implies that the safety concerned with burst failures should be guaranteed. From this consideration, carbon fiber reinforced polymer (CFRP) is chosen as the material for the flywheel, since it is lighter and yet stronger than steel.In vehicle applications, flywheels also act as gyroscopic body, since the angular momentum is typically of a similar order of magnitude as the forces acting on the moving vehicle. This property may be detrimental to the handling characteristics. Besides, this property could be utilized to improve stability in curves. Conversely, the effect can be almost completely removed by mounting the flywheel within an appropriately applied set of gimbals, where the angular momentum is conserved without affecting the vehicles. We achieved good performance of flywheel supported by zero-bias AMBs by means of controllers which significantly compensate gyroscopic effects. The flywheel can rotate up to 300Hz without any gyroscopic effect. We mounted FESS on an electric vehicle (EV) and designed electric power converter to charge/discharge the energy. We developed and implemented new algorithm to compensate gyroscopic effect while EV is turning. This report describes experimental results including maneuverability and overall energy efficiency, including the results of outdoor field experiments such asfeasibility test of steer-by-wire system, implementation of input shaping to reduce vibration and gyroscopic effects, simple adaptive control method for flywheel attitude control, and the efficiency measurement of the energy conversion system. Less