【作者】 向鑫；

【导师】 何湘宁； 李武华；

【作者基本信息】 浙江大学 ， 电力电子与电力传动， 2014， 硕士

【摘要】 随着能源危机和环境危机的日益加剧,世界各国都开始关注清洁能源的发展和可再生能源的利用,以风能和太阳能为代表的分布式能源已逐渐成为学术界和工业界的研究热点[1-2]。但由于分布式发电空间分布的广泛性和时间分布的随机性,当分布式发电渗透率逐渐升高时,现有的电力系统在结构和设计理念上都面临着很大的挑战。为解决这一实际问题,美国学者于本世纪初首先提出了微网的概念。近年来,对微网的研究已成为国内外电气工程领域的一个热点问题[3-5]。本论文基于直流架构的微网系统,主要研究用于直流微网系统的全功率风力发电控制策略、高增益光伏接入拓扑以及系统控制与能量管理机制。1.在直流微网系统风力发电单元,本论文利用反电势估算法原理,实现了基于内置观测器的永磁电机位置估测矢量控制策略。在此基础上采用风机内在功率特性MPPT策略,实现了最大风能捕获和功率管理,并利用李雅普诺夫第一定理证明了这种策略在整个工作范围内的稳定性。同时,搭建了一套5kW永磁电机实验测试平台,对此控制策略的有效性进行了实验验证。2.在直流微网系统光伏发电单元,在总结现有高增益光伏接入拓扑的基础之上,提出了一种基于耦合电感倍压结构的有源箝位Boost高增益变流器拓扑结构。利用耦合电感倍压结构引入了一个新的升压控制自由度,实现了在常规占空比条件下的高升压。同时,又利用耦合电感中的原边漏感实现了主开关管的ZVS软开通。实现了将光伏组件输出的较低直流电压高效率地提升至满足并网单元需求的直流母线电压的转换任务。在实验室制作了一台实验样机,验证了此新型变流器在光伏发电应用场合的有效性。3.根据直流微网系统的控制要求,本论文选择层次控制为整个系统的控制架构方案,并相应提出了变流器控制层,母线控制层以及调度管理层的层次控制结构。在变流器控制层中,为各变流器建立了简化模型。在母线控制层中,介绍了系统中各个单元模块的控制算法,以及根据母线电压协调各单元运行的机制,保证系统稳定运行。最后,在实验室搭建了一套直流微网测试平台,通过多组实验验证了理论分析的正确性和可靠性。更多还原

【Abstract】 With the growing energy crisis and environmental problems, many countries around the world are concerned about the development of renewable energy.The distributed energy, such as wind energy and solar energy, has become a hotspot both in academic and industrial areas.However, due to the extensiveness and randomness of distributed generation in space and time, when the penetration of distributed generation increases, the existing power system faces great challenges. To solve this problem, some American researchers proposed the concept of microgrid at the beginning of this century. In recent years, the research for microgrid has become one of the hottest topics in Electrical Engineering community. The major research of this paper forcuses on the topology and control of Wind/PV interfaces for DC Microgrid.1. In wind power generation, Back-EMF algorithm based on state observer is used to realize the sensorless FOC for PMSG. On this basis, the inherent MPPT strategy is utilized to achieve the maximum energy capture and power management. Meanwhile, the stability of this strategy over the entire operating range is proved by the first theorem of Lyapunov. Finally, a5kW platform is built and the effectiveness of the control strategy is validated.2. In PV generation, taking advantage of the existing high step-up converters, a single phase high step-up converter with improved multiplier cell is proposed. The coupled inductor voltage doubler cell is introduced and provides another control freedom to achieve large voltage conversion ratio. Besides, leakage inductance of coupled inductor is used to achieve ZVS soft switching of all the switches. This converter realizes the conversion of low PV voltage to high bus voltage which is required by the grid-connected inverter. In laboratory, a prototype is built and the effectiveness of this novle converter in photovoltaic applications is verified.3. According to the requirements of DC microgrid, this paper selects the hierarchical control schemes for the system. Furthermore, converter control level, bus regulation level and scheduling management level are proposed in this paper. In the converter control level, all the converters can be represented as a controllable current source. In the bus regulation level, all the converters have their own control algorithms. According to the variation in bus voltage, each module in DC microgrid can work in three different modes to ensure the stable operation of the system. Finally, a set of DC microgrid platform is built and a set of experimental results verify the feasibility of the theoretical analysis.更多还原