【作者】 张伟；

【导师】 卢锦玲；

【作者基本信息】 华北电力大学 ， 工程硕士（专业学位）， 2021， 硕士

【摘要】 面对化石能源消耗及其带来的环境污染问题,寻求并利用可替代的清洁能源已成为目前热门的研究方向。微电网能够有效利用清洁的分布式电源,然而单个微电网没有大电网支持时,将面临功率调节难度大和供电可靠性低的问题。将若干个微电网连接到临近的同一馈线上构成微网群系统,通过功率互济,能够有效改善各微电网的稳定性。光伏发电与混合储能相结合构成的微电网系统不仅可以克服光伏输出功率的间歇性与波动性问题,而且还能够解决单一储能电池的不足与局限性。因此,本文基于光伏与混合储能微电网,对光/储微网群的协调控制策略进行了分析研究。首先,研究了光伏系统的基本工作原理,利用数学模型和建模仿真分析其输出特性。然后对铅酸蓄电池、超级电容器的基本原理、模型及其连接结构进行了分析研究,搭建了含混合储能的光伏微电网系统。然后对微网群系统架构及其协调控制策略进行研究。提出了一种分层与主从控制相结合的混合控制方法,将微网群分为三层结构:单元层、微电网层及微网群层,微网群层将微电网作为控制单元,群控制器采用主从控制将各子微电网分为主从微网,各微电网系统包含单元层和微电网层控制策略。单元层光伏系统利用改进型变步长扰动观察法来实现最大功率点跟踪;提出了一种二阶低通滤波方法对混合储能单元承担的功率进行分配,并结合其荷电状态限值管理策略,合理划分混合储能工作状态,并控制光伏变换器运行在MPPT或恒压降功率模式。然后研究了微电网层双向DC/AC变换器的控制策略,使其在并网或离网状态下稳定运行。最后根据本文提出的功率管理与协调控制策略,在ulink Matlab/Sim平台上搭建仿真系统验证了光伏和储能微电网控制策略的可行性与有效性,同时可以看到混合储能系统的优势和必要性。然后以此微电网为基础,搭建光/储微网群系统仿真模型,通过不同运行工况下的仿真来验证本文提出的光/储微网群协调控制策略的可行性和有效性。更多还原

【Abstract】 Facing the problem of fossil energy consumption and environmental pollution,seeking and utilizing alternative clean energy has become a hot research direction.Microgrid can effectively use clean distributed power sources,However,when a single microgrid is not supported by distribution network,it will face the problems of difficult power regulation and low power supply reliability.Several microgrids are connected to the same feeder adjacent to each other to form a microgrid cluster system,which can effectively improve the stability of each microgrid through mutual power supply.The microgrid system composed of photovoltaic power generation and hybrid energy storage can not only overcome the intermittent and fluctuating problems of photovoltaic output power,but also solve the shortcomings and limitations of a single energy storage battery.Therefore,based on the photovoltaic and hybrid energy storage microgrid,this paper analyzes and studies the coordinated control strategy of the photovoltaic/energy storage microgrid group.First,the basic working principle of the photovoltaic system is studied,and its output characteristics are analyzed by mathematical model and modeling simulation.Then,the basic principle,model and connection topology of lead-acid battery and supercapacitor are analyzed and studied,and a photovoltaic m icrogrid system with hybrid energy storage is built.Then,the architecture and coordination control strategy of microgrid cluster system are studied.A hybrid control method combining hierarchical control with master-slave control is proposed,and the microgrid cluster is divided into three layers:unit layer,microgrid layer,and microgrid cluster layer.The microgrid cluster layer takes the microgrid as the control unit,and the cluster controller adapts master-slave control to divide each sub-microgrid into a master-slave microgrid.Each microgrid system includes unit layer and microgrid layer control strategies.The improved variable step disturbance observation method is used to achieve maximum power point tracking in the unit layer photovoltaic system;A second-order low-pass filtering method is proposed to allocate the power borne by the hybrid energy storage.Combined with the state of charge limit management strategy,the hybrid energy storage working state is reasonably divided,and the photovoltaic converter is controlled to operate in MPPT or constant voltage drop power mode.Then,the control strategy of bidirectional DC / AC converter in microgrid layer is studied to make microgrid operate stably in grid-connected or off-grid state.Finally,according to the proposed power management and coordinated control strategy,a simulation system was first built on the Matlab/Simulink platform to verify the feasibility and effectiveness of the photovoltaic and energy storage microgrid control strategy.At the same time,the advantages and necessity of the hybrid energy storage system can be seen.Then,based on the microgrid,a simulation model of photovoltaic/energy storage microgrid cluster system is built.Through the simulation of different operating conditions,the feasibility and effectiveness of the coordinated control strategy of the photovoltaic/energy storage microgrid cluster proposed in this paper is verified.更多还原