【作者】 杨欢；

【导师】 赵荣祥；

【作者基本信息】 浙江大学 ， 电机与电器， 2008， 博士

【摘要】 传统化石能源紧缺、环境危机、集中式供电模式下的局限性等问题促使越来越多的人开始关注混合能源系统。区别于一般分布式供电系统,混合能源系统具有两大特点,一是通过系统内部多种微型能源与储能装置的合理配置实现优势互补,二是通过执行负荷均衡化的控制策略来实现用户侧高标准电能需求与实际电能供给的一致性。作为用于实现这些特点的两个关键部件,混合能源系统中的储能装置和并网变换器成为论文的研究重点。论文从建立一个典型混合能源系统的角度出发,对混合能源系统的结构、部件选择、部件建模、主电路设计等理论问题进行了系统的分析与总结,然后针对飞轮储能装置以及多功能并网变换器这两个关键部件,通过理论分析、仿真验证以及实验进行了深入的应用研究。首先,论文基于对储能装置各项指标的总结、比较以及混合能源系统中的具体储能要求,选择飞轮储能装置和钠硫电池储能装置作为系统中的储能环节。随后从负荷均衡化控制策略的思路出发,提出了多功能并网变换器的概念,并根据多功能并网变换器功能复合化的要求,在三相四线制电网背景下,对电容中分式、四桥臂式、三单相全桥式并网变换器的拓扑进行了深入的建模与量化对比分析,最终给出了合适的并网变换器拓扑。其次,在确定了各部件的选择和功能定位后,论文对光伏电池、钠硫电池以及飞轮储能装置的特性进行了全面的分析,建立了相关的等效电路模型、热模型、性能评价指标以及机电方程,同时给出了适合它们的电力电子接口电路,接着对并网变换器的控制模型进行了简要分析,并通过仿真分析对这些模型进行了验证。完成了混合能源系统实验样机的主回路设计。对于飞轮储能装置,论文给出了选择高强度飞轮材料、形状以及加工工艺的建议,随后对驱动高速飞轮的电机类型进行了简要的探讨,最后对飞轮储能装置中的轴承解决方案进行了重点研究。论文根据卧式和立式两种飞轮结构,提出了三极式逆变器供电的电磁径向轴承和交错式永磁轴向推力轴承这两种新型轴承。对于三极式逆变器供电的电磁径向轴承,论文通过基于等效磁路法的解析分析以及有限元仿真分析软件的验证,得到了该轴承转子的电磁力状态方程,根据该方程的解耦特点提出了基于位移PID控制与电流滞环控制的双闭环控制方法,并通过先进的场路耦合仿真技术对该种控制方法进行了验证。对于交错式永磁轴向推力轴承,论文提出基于电流片模型对该轴承的磁力进行解析建模,得到了一个便于求解的可用于单对或多对同轴磁环或者磁块阵列磁力计算的解析表达式,随后通过两维和三维有限元仿真分析软件的计算对该解析表达式进行了验证。根据该表达式,完成了交错式永磁轴向推力轴承的设计与制作,并最终通过所搭建的飞轮储能实验平台对该种推力轴承的性能进行了实验验证。由于多功能并网变换器在执行负荷均衡化策略时,具体的软硬件实现上会发生相应的变化,论文首先对多功能并网变换器的控制结构与主电路结构进行了分析,根据这些结构的特点对电流指令信号的获取、电网接口电路的设计进行深入的分析。其中针对谐波检测在具体电路实现时所遇到的硬件电路延时与硬件电路检测误差问题,分析了采用无锁相环技术对谐波检测带来的影响,并引入通用瞬时无功理论中的波形相关系数概念,分析了硬件延时对检测精度的影响,提出了一种考虑硬件延时补偿的无锁相环同步坐标变换检测法,并进行了仿真的验证。随后论文提出利用隔离变压器的漏抗与传统LC滤波器构成对高频信号抑制能力更强的LCL滤波器作为多功能并网变换器的并网接口电路,并给出了相应的设计原则。最后在前述工作基础上对多功能并网变换器的硬件电路实现与控制软件设计进行了介绍,完成了一台15kVA三单相全桥结构多功能并网变换器的制作。更多还原

【Abstract】 Due to the shortage of fossil fuel, the environmental crisis and the limitations of concentrative power generation, hybrid energy system (HES) has attracted more and more attention. HES has two remarkable features compared with normal distribution generation systems, one is the complementary advantage achieved by the rational allocation of microsources and energy storage systems, and the other is the load leveling control strategy which could make balance between the customers’ high level demand and the real power supply. As the key components to realize the two features of HES, the energy storage system and the grid-connected converter are the main research issues in this dissertation. In order to establish a typical HES prototype, some theoretical problems are analyzed and summarized in this dissertation, such as HES configuration, selection and modeling of components, main circuit design and so on. Next the flywheel energy storage system and the multifunctional grid-connected converter are further studied by theoretical analysis, simulation and experimental validation.First of all, based on the comparison and the summary on some indexes of different energy storage systems and the requirements of the HES prototype, flywheel and sodium-sulfur battery are selected as the energy storage systems in the HES prototype. Then the concept of multifunctional converter is presented according to the load leveling control strategy, and the topology selection for the multifunctional converter in three-phase four-wire power system is made. As per modeling and quantitative analysis of three-leg split-capacitor topology, four-leg topology and three single-phase full bridge topology, the appropriate topology is finally proposed.Secondly, after the components selections and their function orientation are defined, a comprehensive analysis is elaborated on the characteristics of photovoltaic battery, sodium-sulfur battery and flywheel energy storage system (FESS). According to this analysis, the equivalent circuit model, the thermal model, the evaluation indexes, the electromechanical state equation as well as the corresponding power electronic interfaces are consequently presented. The transfer function for grid-connected converter is also given. These models are verified by simulation results. Therefore the main circuit deign for HES is completed.Concerning FESS, some advices on material, shape and processing technology for high strength flywheel are given, and some different types of driving motors for high speed flywheel are discussed. In terms of the solution for the bearings in FESS, two novel bearing configurations for both vertical and horizontal flywheel are proposed. For the three-pole inverter-fed active magnetic bearing, the state equation for magnetic force on rotor is presented on the basis of equivalent magnetic circuit, and the analytical results are verified by finite element analysis (FEA) simulation. Owing to the decoupled analytical model, a control method with PID displacement control in the outer loop and hysteresis current control in the inner loop is proposed. The performance of the control method is verified by advanced simulator coupling technology. For interleaved permanent magnet thrust bearing, based on the current sheet model, a simple form analytical solution for the analysis and design of permanent magnet (PM) thrust bearing is proposed. It could be used for magnetic force calculation of single or multiple pairs PM arrays or PM rings. The accuracy of the analytical solution is verified by 2D and 3D FEA simulation. According to the analytical solution, a prototype PM thrust bearing with the proposed configuration is designed and fabricated, whose performances are experimentally validated on the FESS test platform.When load leveling control strategy is applied in multifunctional grid-connected converter, the realization in hardware and software will change accordingly. Based on the analysis of control structure feature and main circuit configuration feature in multifunctional grid-connected converter, the harmonics detection and interface circuit between converter and grid are further studied. The phase lock loop detection error and the time delay often occur in the digital control circuit for harmonics detection. In order to minimize their bad influences, the performance of the harmonics detection method without phase lock loop is discussed, and meanwhile the effect of the time delay on the reference compensation current signal is investigated based on universal instantaneous power theory. Then an improved synchronous reference frame method for harmonics and reactive currents detection is proposed in the dissertation, which applies no phase lock loop and takes the time delay into account. The simulation results have proved its accuracy and feasibility. Then a LCL filter formed by traditional LC filter and the short circuit impedance of isolation transformers is proposed, which has better filter characteristics. And some design principles for the LCL filter are also given. Last but not least, the control circuit accomplishment and the software flow chart are introduced, and the fabrication of a 15kVA three single-phase full bridge multifunctional grid-connected converter prototype is finally completed.更多还原