A Study on Flywheel Energy Storage System Mounted on Electric Vehicle

飞轮储能系统(FESS)的工作原理是将飞轮加速到高速旋转，并将系统中的能量保持为动能。通过减慢飞轮的速度，能量被转换回来。一个典型的系统由一个由真空室内的轴承悬挂的转子组成，以减少摩擦，并连接到一个组合的电机/发电机。主动磁轴承(AMB)是提高总能效所必需的。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。在这样的背景下，由于磁悬浮轴承在高速旋转时具有无接触、无摩擦等显著优点，我们一直致力于磁轴承在FESS中的应用。通常情况下，磁悬浮轴承主要应用在环境不可移动的系统中。相反，我们开发了一种飞轮车辆，采用磁力轴承和万向节机构作为储能系统。飞轮助力汽车…更多的S(主要是机械的，或机械轴承)早在很久以前就被开发出来了，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。提议的飞轮系统将消除现有电池系统的缺点，如功率密度低、充电时间长、重量重、寿命短和铅污染。飞轮的缺点是很难长时间储存能量。而且，高速旋转意味着与突发故障有关的安全性应该得到保证。考虑到这一点，碳纤维增强聚合物(CFRP)被选为飞轮的材料，因为它比钢更轻但更坚固。在车辆应用中，飞轮也充当陀螺仪主体，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。这一特性可能不利于操控特性。此外，这一性质还可以用来提高曲线的稳定性。相反，通过将飞轮安装在适当应用的万向架中，几乎可以完全消除这种影响，其中角动量是守恒的，而不会影响车辆。通过控制器实现了零偏磁轴承支承的飞轮的良好性能，显著补偿了陀螺效应。飞轮可以旋转高达300赫兹，没有任何陀螺效应。我们将FESS安装在电动汽车上，并设计了电力转换器来对能量进行充放电。提出并实现了电动汽车转弯时陀螺效应补偿的新算法。本文描述了包括操纵性和整体能效在内的实验结果，包括线控转向系统的可行性测试、采用输入整形以减小振动和陀螺影响、飞轮姿态控制的简单自适应控制方法以及能量转换系统的效率测量等户外现场实验的结果。较少

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