【作者】 汤平华；

【导师】 李铁才；

【作者基本信息】 哈尔滨工业大学 ， 电机与电器， 2010， 博士

【摘要】 飞轮储能系统是一种新型的机电能量转换与存储装置,具有使用寿命长、转换效率高、适应性强以及无污染等优点,在航空航天、分布式发电、电力调峰以及电动汽车等领域有着广泛的应用前景。飞轮储能技术是一种多学科交叉的高科技新技术,涉及磁悬浮、高速电机、真空处理、电力电子以及复合材料等技术,被认为是未来最有应用价值的能量存储方式之一,其研究内容非常丰富。本文的研究课题来源于深圳市重点科技研究项目——分布式自主能源系统前期研究,主要包括磁悬浮轴承、飞轮储能用电动机/发电机(本文定义为飞轮储能电机)以及飞轮储能电机驱动系统控制三个方面的研究内容。磁悬浮轴承能够解决传统轴承磨损、润滑等方面的问题,是飞轮储能系统的关键技术。本课题采用由轴向永磁磁悬浮轴承与径向无源电动磁悬浮轴承组成的全被动磁悬浮轴承结构,永磁磁悬浮轴承用于支撑飞轮质量,无源电动磁悬浮轴承用于保持飞轮径向稳定。无源电动磁悬浮轴承在直线运动应用场合的研究获得了很多可喜成果,但在旋转运动尚处于起步阶段,是飞轮储能领域的研究难点。本文提出新型的径向无源电动磁悬浮轴承结构:定子采用相斥磁场结构,转子采用单层或双层8字形线圈结构。然后利用解析法和有限元仿真分析法对相斥磁场特性、8字形线圈受力、转子受力、以及轴承损耗等进行研究。为验证径向轴承的理论分析和仿真研究的正确性,设计一个径向轴承样机及测试平台进行实验研究,使转子高速稳定旋转、可以方便观察轴承定子的运动状态、并测得定子的偏移量和受力关系。飞轮储能电机实现电能与机械能的相互转换,是飞轮储能系统的关键部件。为提高能量的转换效率和系统的集成度等性能,提出选用无铁心永磁方波无刷飞轮电机作为能量转换的电动机/发电机。该种电机无定子铁损和转子铜损,使电机空载运行时主要损耗为绕组的涡流损耗、负载运行时主要损耗为绕组涡流损耗与转子涡流损耗。为减小绕组涡流损耗,建立其理论估算模型,并对一台样机进行绕组涡流损耗估算,再利用自由停机的实验方法验证估算模型的有效性。分析确定转子涡流损耗的来源为电枢反应,并提出内、外等效电流层求解电枢反应场的方法;为减小转子损耗,保证电机负载时高效运行,详细分析了空间谐波和时间谐波产生损耗的原理,并提出改变风损的实验方法对转子损耗进行分离,实验结果与有限元仿真计算结果进行比较,验证实验方法的有效性,同时验证有限元计算结果的可靠性。无铁心永磁方波无刷飞轮电机具有小电感的特点,会造成升速过程中稳态电流波动大的问题,而且采用方波控制时,存在换相电流波动,增加了充电过程的控制难度;为减小充电时电机稳态电流波动大的问题,提出方波倍频PWM控制与母线电压调节控制相结合的方法,并利用Matlab系统仿真和实验研究验证控制方法的可行性。为减小电机的换相电流波动,提出利用新型三相逆变器和母线电流检测方法,获得全范围内完整的电流信息,实现高质量的电流反馈控制。系统放电时,随着转速的降低输出电势越低,造成驱动系统放电控制的难度增大。为保证系统放电的安全性,利用Boost电路先升压再逆变输出的方法,并用Matlab仿真验证该方法的有效性。最后,设计实现一个基于TMS320F2812 DSP的飞轮储能电机驱动系统的数字控制最小系统。重点介绍了系统的硬件设计和软件设计,以满足飞轮储能系统的控制要求;并且利用该最小系统对飞轮储能系统样机进行了实验研究,实验结果与仿真结果进行对照,验证控制方案的实用性。更多还原

【Abstract】 Flywheel energy storage system is a kind of novel electromechanical energy conversion device with several advantages, including long-life, high efficiency, strong adaptablility and no pollution etc. There is extensive application foreground in mang fields, such as aerospace, distributed electricity generation, electric power peak adjustion, and electromotion vehicle so on. Flywheel energy storage technology is a kind of cross technology with several high and new technology, including magnetic suspension technology, high speed electric machine technology, vacuum technology, power electronics technology and composite material technology etc., and it is deemed to be one of the most valuable energy storage technology, so, the relative study content is very abundant. The research task of this paper comes from the Key Science and Technology Research Project of Shenzhen City Government——Early Research of Distributed Self-determination Energy System, and the main study contents of this paper include three parts: magnetic suspension bearing, motor/generator for flywheel energy storage(flywheel electric machine for energy storage) and control of flywheel electric machine drive system for energy storage.Magnetic suspension bearing technology is one of the key technologies of flywheel energy storage. This project proposes full passive magnetic suspension bearing structure which consisits of axial permanent-magnet suspension bearing and radial passive electromotive magnetic suspension bearing to remove abrasion and lubrication of traditional bearing. Axial permanent-magnet bearing is used to support the mass of flywheel rotor, radial passive electromotive magnetic bearing is used to keep radial stable suspension of flywheel. There are many delightful research achievements of passive electromotive magnetic bearing in linear-motion occasion, but the research of passive electromotive magnetic bearing is in initial starting stage in rotating occasion, and it is a difficult point of magnetic bearing field. This paper proposes a new stucture of passive electromotive magnetic bearing which inclues two parts: stator supplys repulsive magnetic field, and rotor selects single-layer 8-shape coil structure or double-layer 8-shape coil structure. And then several contents which include characteristics of repulsive magnetic field, force of 8-shape coil, force of rotor, and stabilization of bearing etc., are studied with theoretical analysis scheme and finite element analysis(FEA) scheme. Finally, a prototype and a test device for radial passive electromotive magnetic bearing is designed to validate theory analysis and simulation study; this device can assemble rotor to implement high speed rotation, conveniently observe movement process of stator, and measure the relative data between departure length and force of stator.Flywheel electric machine for energy storage which is the carrier of energy between electrical energy and mechanical energy is another key part of flywheel energy storage. Ironless permanent magnet square-wave flywheel electric machine is selected in this paper to improve some characteristics of energy storage system, such as efficiency, integration level etc. This type of electric machine has no copper loss of rotor and no iron loss of stator, so, the main loss is winding eddy loss without load, and the main loss includes winding loss and rotor eddy loss with full load. Theory estimation calculation model is modeled to reduce winding eddy loss, and the winding eddy loss of a prototype is estimated with the proposed model, finally validated by experiment of free halt. The rotor eddy loss maily comes from armature reaction, and the field resolution scheme is proposed using equivalent current layer which includes inner layer and outer layer to get the distribution of armature reaction field; to reduce rotor eddy loss and obtain high efficiency, the principle of loss caused by space harmonics and time harmonics is analyzed in detail, then, a experimental scheme to measure rotor eddy loss by changing windage loss is propsed, and the experiment results compare with FEA calculation results to validate the proposed experiment scheme, furthermore, the reliability of FEA calculation is also demonstrated.During the charge period, ironless permanent magnet square-wave brushless electric machine is difficult to drive because the little phase-inductance causes large steady-state current ripple with PWM control scheme; furthermore, large phase-conversion current ripple will be produced while the motor/generator is driven by square-wave control scheme. So, the large steady-state current ripple and large phase-conversion current ripple will increase the control difficulty. This paper proposes a novel control scheme including double-frequency PWM(pulse width modulation) square-wave control and DC voltage adjustion to reduce steady-state current ripple, and the proposed scheme is validated by Matlab simulation and experiment. Then, novel three-phase inverter and bus current detecting shceme which are to obtain all current information are proposed to reduce phase-conversion current ripple of square-wave motor, and the proposed scheme is also validated by Matlab simulation and experiment. During the discharge period, the output voltage decreases with the speed of electric machine, which increases the control difficulty for discharge. So, a converter for discharge which includes a Boost circuit and a single-phase inverter circuit is presented to obtain stable and safety output, and the proposed scheme is also validated by Matlab simulation.Finally, a digital minimum drive system for electric machine drive of flywheel energy storage based on TMS320F2812 DSP is designed. To satisfy control requirement of flywheel energy storage system, this paper mainly introduces hardware design and software design, and experimental research of flywheel energy storage system prototype is implemented with the minimum system, then experimental results compare with simulation results to validate practicability of system control scheme.更多还原