单相光伏逆变器并离网控制系统设计

发布时间：2018-01-07 10:34

本文关键词：单相光伏逆变器并离网控制系统设计　出处：《温州大学》2015年硕士论文　论文类型：学位论文

【摘要】：分布光伏并网发电系统近年来发展迅速,并网逆变器作为分布式发电系统与电网的接口电路得到了广泛的应用。为保证本地敏感负载的供电可靠性,分布式并网逆变器一般具并网运行模式和离网独立运行模式,因此逆变器在两种模式之间的无缝切换,保证本地负载供电的连续性成为一大难题。本文正是针对上述难题,设计了单相光伏逆变器的并离网控制系统。(1)本文分析了国内外光伏发电的发展趋势。光伏发电作为一种新型的可再生能源,其具有的一系列特殊优势以及广泛的应用前景。阐述了并离网无缝切换概念,总结了目前国内外针对并网离切换研究的难点与热点。(2)针对单相逆变器拓扑结构,建立了逆变器并网运行模式和离网独立运行模式的数学模型,并在此基础上提出了相对应的控制策略。设计了一种改进的离散比例谐振控(DPR)制器,论证了该控制器在离散域到交流参考信号跟踪的无差性。(3)提出了针对单相并离网系统的软件闭环锁相方法与孤单检测方法。设计了一种改进的单相闭环锁相方法,论证了该锁相方法中生成的正交性号具有无差性。(4)针对逆变器在双模式之间切换时存在的各种问题,设计了一种并离网无缝切换方法,并给出了逆变器详细的切换流程。(5)针对目前各种光伏电池最大功率跟踪(MPPT)算法的优势与缺陷,提出了两级式光伏逆变系统在并离网双模式下的前后级控制策略。最后,通过实验平台测试结果分析,表明本文设计的控制系统能够实现并网逆变器并网运行模式与离网独立运行模式之间的无缝切换,保证本地负载在逆变器两种模式切换过程中的连续供电,满足设计需求。
[Abstract]:Distributed photovoltaic grid-connected generation system has been developed rapidly in recent years. Grid-connected inverter is widely used as the interface circuit between distributed generation system and power grid to ensure the reliability of local sensitive load. Distributed grid-connected inverter generally has grid-connected operation mode and off-grid independent operation mode, so the inverter switches seamlessly between the two modes. To ensure the continuity of local load power supply has become a major problem. This paper analyzes the development trend of photovoltaic power generation at home and abroad. Photovoltaic power generation as a new type of renewable energy. It has a series of special advantages and wide application prospects. This paper summarizes the difficulties and hotspots in the research of grid-connected and off-grid switching at home and abroad. Aiming at the topology of single-phase inverter, the mathematical models of grid-connected operation mode and off-grid independent operation mode are established. Based on this, a corresponding control strategy is proposed and an improved discrete proportional resonance control (DPRR) controller is designed. It is proved that there is no difference between the controller and AC reference signal tracking in discrete domain. A software closed-loop phase-locking method and a lonely detection method for single-phase parallel and off-grid systems are proposed, and an improved single-phase closed-loop phase-locking method is designed. It is demonstrated that the orthogonality number generated in this phase-locked method has no difference. (4) aiming at the problems existing in switching between two modes of inverter, a seamless switching method is designed. A detailed switching flow of the inverter. 5) aiming at the advantages and disadvantages of various MPPTs for maximum power tracking of photovoltaic cells is given. The control strategy of two-stage photovoltaic inverter system in parallel and off-grid dual-mode is proposed. Finally, the test results are analyzed by the experimental platform. It shows that the control system designed in this paper can realize seamless switching between grid-connected inverter grid-connected operation mode and off-grid independent operation mode, and ensure the continuous supply of local load in the switching process of two modes of inverter. Meet design requirements.
【学位授予单位】：温州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM464;TP273

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