光伏电源作为虚拟同步发电机运行控制方法研究

发布时间：2019-01-22 13:35

【摘要】：受可再生能源大规模并网的影响,包括光伏电源在内的分布式电源在电网中的渗透率近年来急剧增加,对电力系统稳定运行带来了严峻的挑战和考验。虚拟同步发电机控制是一种电网友好型技术,能够使分布式逆变电源表现出与同步发电机相同的运行特性,增强电网对可再生能源的接纳能力。本文结合光伏发电与虚拟同步发电机技术,研究了光伏电源作为虚拟同步发电机的运行控制方法。首先建立了包含光伏电源、储能设备的虚拟同步发电机系统拓扑结构,并对光伏阵列和超级电容器进行数学建模,将同步发电机运行特性引入到逆变器控制当中,分析了虚拟同步发电机的控制原理。其次,对已有虚拟同步发电机实现方案进行归纳,建立了虚拟同步发电机在离网/并网模式下的小信号模式,对三种控制策略的动态、静态特性进行了分析与比较,针对各策略的使用条件和控制参数选择等问题进行了讨论,研究了三种策略的开机启动性能。通过综合不同控制策略优点,对原有控制方案进行了改进。再者,基于改进后的控制方法,研究了含光伏-储能的虚拟同步发电机系统在并网模式下的协调控制策略,通过能量管理对直流/交流两侧的能量流动关系进行协调,利用超级电容器充放电补偿暂态过程中出现的不平衡功率,减小光伏输出功率突变对电网的冲击,并稳定直流母线电压;将储能设备荷电状态信息传递给虚拟同步发电机控制,以便调整系统的有功功率输出,避免荷电状态出现异常。最后,为运行于独立微网中的光伏-储能系统设计了一种能量管理控制策略,并引入了自适应下垂特性的概念,结合调整下垂斜率和平移下垂特性的方式,使光储发电系统能根据运行条件自主切换工作模式、改变功频输出和光能摄入,实现光储系统的无互联信号自治管理及对独立微网持续运行的主动支撑,避免了模式切换可能对系统稳定性造成的影响。
[Abstract]:Influenced by the large-scale grid connection of renewable energy, the permeability of distributed generation, including photovoltaic power, has increased dramatically in recent years, which has brought severe challenges and tests to the stable operation of power system. Virtual synchronous generator control is a kind of grid-friendly technology, which can make the distributed inverter generator show the same operating characteristics as synchronous generator, and enhance the power grid's ability to accept renewable energy. Combined with photovoltaic generation and virtual synchronous generator technology, the operation control method of photovoltaic power supply as virtual synchronous generator is studied in this paper. Firstly, the topology of virtual synchronous generator system including photovoltaic power supply and energy storage equipment is established, and the mathematical model of photovoltaic array and supercapacitor is established, and the operation characteristics of synchronous generator are introduced into inverter control. The control principle of virtual synchronous generator is analyzed. Secondly, the implementation scheme of virtual synchronous generator is summarized, and the small signal mode of virtual synchronous generator in off-grid / grid-connected mode is established. The dynamic and static characteristics of three control strategies are analyzed and compared. The use conditions and control parameters of each strategy are discussed, and the startup performance of three strategies is studied. By synthesizing the advantages of different control strategies, the original control scheme is improved. Furthermore, based on the improved control method, the coordinated control strategy of the virtual synchronous generator system with photovoltaic and energy storage in grid-connected mode is studied, and the energy flow relationship between DC and AC is coordinated by energy management. Using supercapacitors to compensate the unbalanced power in the transient process, the sudden change of photovoltaic output power is reduced and the DC bus voltage is stabilized. The charging state information of the energy storage equipment is transferred to the control of the virtual synchronous generator in order to adjust the active power output of the system and avoid the abnormal charging state. Finally, an energy management control strategy is designed for the photovoltaic energy storage system running in an independent microgrid, and the concept of adaptive sag characteristics is introduced. The optical storage power generation system can change the mode of operation independently according to the operating conditions, change the power and frequency output and light energy intake, realize the autonomous management of the signal without interconnection and the active support for the continuous operation of the independent microgrid. The effect of mode switching on system stability is avoided.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM341

【参考文献】