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飞轮电池磁悬浮支承系统理论及应用研究
Research on Theory of Magnetic Suspension Supporting System and Application for Flywheel Battery
【作者】 汤双清;
【导师】 廖道训;
【作者基本信息】 华中科技大学 , 机械设计及理论, 2004, 博士
【摘要】 飞轮电池由于具有一系列独特的性能,已经成为电池行列一支新生的力量,并在许多方面有取代化学电池的趋势。随着新型复合材料和稀土永磁材料、电机技术、磁悬浮技术和电力电子技术的飞速发展,其应用涉及到航空航天、电动汽车、分布式发电系统、电力质量与蓄能发电、不间断电源等等领域。本文对飞轮电池系统方案、磁悬浮支承系统的理论与计算方法和飞轮电池在分布式发电中的应用等方面进行了全面、系统的研究。本文所做工作和创新主要表现在如下几个方面:提出了一种新型的磁悬浮轴承(本文称它为电动磁力轴承)。对电动磁力轴承的工作机理、转子受力、轴承刚度以及稳定性等方面进行了深入的理论研究,提出了电动磁力轴承的悬浮力、刚度、最低稳定运转转速和临界阻尼计算的理论和方法。全面系统地提出了永磁体空间磁场计算的理论与方法。分别利用永磁体的两种等效物理模型(等效磁荷模型和等效电流模型),推导出永磁体空间磁场计算的数学表达式,还对具有对称形体的永磁体推导出其轴线上磁场计算的解析式。利用有限元理论,提出了包括非均匀各向异性介质在内的永磁体空间磁场计算的理论和方法。提出了永磁磁力轴承的构形综合,发展和完善了磁力轴承悬浮力计算的理论和方法。按照拓扑学理论研究了永磁磁力轴承的构形综合,给出了几种常用的永磁轴承构形。利用并矢、矢量和张量运算理论推导出Maxwell磁场张量,发展和完善了基于Maxwell磁场张量的永磁轴承悬浮力计算的理论和方法。利用虚功原理,结合有限元理论和矢量微分运算法则,发展和完善了基于虚功原理的永磁轴承悬浮力计算的理论和方法。提出了永磁磁力轴承刚度计算的理论和方法。利用标量和矢量的微分运算法则,结合有限元理论,给出了永磁轴承刚度计算的理论和方法,同时对平面磁隙和锥面磁隙两种永磁轴承的轴承特性进行了对比分析。利用电动磁力轴承和锥面磁隙的永磁轴承,提出了用于飞轮电池转子支承的一种全新的磁悬浮支承系统方案。结合分布式发电,提出了用飞轮电池调节小型太阳能发电站输出特性的系统控制方案;分析了用正弦波脉宽调制(SPWM)原理调节电动机/发动机输入/输出电压的幅值、频率和波形的原理和方法。以民用家庭2kW负载为例,仿真了飞轮电池储能变化、电动机/发电机的功率变化以及飞轮转子的转速变化。
【Abstract】 Owing to many unique performances, flywheel battery has been becoming a new member of the battery family, and has been taking the place of the chemical battery in many aspects. Along with the fast development of new composite materials, rare earth permanent magnet, electrical machine technology, magnetic suspension technology and power electronics, its application has involved aerospace, electric vehicles, distributing power generation system, electric power quality and energy storage generation, uninterruptible power supplies (UPS), and so on. This paper goes deep into a thorough research on the system scheme of the flywheel battery, theories & calculation methods of the magnetic suspension system, and its application to the distribution generation.The primary innovations of this paper are as follows:A new-type magnetic bearing is proposed, and is called as the electromotive magnetic bearing. Its operational principle, rotor’s magnetic force, bearing’s stiffness and stability, and so on, are studied in detail. The calculation theories and methods of the suspension force, stiffness, lowest rotating speed and critical damping on the electromotive magnetic bearing are proposed. The theories and methods on the spatial magnetic field’s calculation of the permanent magnet are systemically presented. The integral formulae of the spatial magnetic field’s calculation on the permanent magnet are derived according to equivalent magnetic-charge model and equivalent electric-charge model respectively, and the analytic formulae of the spatial magnetic field’s calculation on the symmetrical permanent magnet are derived along their axes. By use of FEM, the theory and method on the spatial magnetic field’s calculation on the inhomogeneous, anisotropic medium is presented. The configuration synthesis is presented, and theory & method of suspension force’s calculation on the permanent magnetic bearing are proposed. According to topology, studies the configuration synthesis of the permanent magnetic bearing, and presents a few kinds of common configurations. Magnetic Maxwell stress tensor is derived by use of vector, dyadic and tensor operation, and the computing theory & method of the suspension force on the permanent magnetic bearing is developed and perfected according to Maxwell stress tensor. Combined with FEM and vector differential operation, the computing theory & method of the suspension force on the permanent magnetic bearing is developed and perfected according to virtual work principle. <WP=6>Theory & method of stiffness calculation on the permanent magnetic bearing are presented. By use of scalar and vector differential operation, combined with FEM, theory & method of stiffness calculation on the permanent magnetic bearing are presented. By the examples of the permanent magnetic bearing, the bearing performances with a common structure and a cone-shaped structure are analyzed respectively.A new-type magnetic suspension support system that is used to suspend the rotor of the flywheel battery is proposed, which is made up of the electromotive magnetic bearing and the permanent magnetic bearing with a cone-shaped magnetic gap. The system control scheme of the output on the solar energy power plant involving the flywheel battery is proposed, and the principle and method of SPWM used to adjust the breadth, frequency and waveform of the output/input voltage on the motor/generator are analysed. By the example of the civil house with 2kW load, simulate the energy variation of the flywheel battery, the power variation of the motor/generator and the speed variation of the rotor.
【Key words】 flywheel battery; electromotive magnetic bearing; permanent magnet bearing; stiffness; damping; finite element method;