含混合储能微电网孤岛运行能量管理策略研究

发布时间：2018-03-09 13:48

本文选题：微电网　切入点：混合储能　出处：《湖北工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着风能、太阳能等分布式电源及其构成的微电网的广泛应用,分布式发电的间歇性、随机性的特点和负荷的波动等对微电网的电能质量和稳定性造成的影响越来越大。利用储能装置可以在一定程度上起到抑制功率波动的作用,但是单一的储能装置难以较好地同时满足功率与能量两方面的要求。利用超级电容与蓄电池组成的混合储能系统能较好实现微电网功率平衡,电能质量的改善,从而提高供电可靠性。本文以光伏微电网系统为研究对象,考虑蓄电池与超级电容的互补特性,对其微电网能量管理策略展开研究。首先,分析了光伏微电网拓扑结构,建议光伏发电单元的等效模型。分析了光伏电池的特性,对光伏电池单元采用最大功率点跟踪(MPPT)控制,以实现最大功率与变功率输出。分析了蓄电池和超级电容的工作特性及输出特性,分别建立等效模型。接着重点分析了混合储能元件变换器的设计,讨论了了双向DC/DC变换器的结构和原理,并设计的变换器的参数。为后面蓄电池和超级电容的功率分配的研究和控制做好理论准备。其次,讨论了混合储能中两种储能元件的几种连接方式,分析其优缺点,确定混合储能采用有源式接法。分析比较了各种混合储能功率分配法,滤波法是采用低通滤波器对波动功率进行分频控制,本文提出了基于荷电状态,不依赖于频率的的功率分配法。接着提出基于变换器的双极式变流器结构,蓄电池和超级电容采用不同的控制策略,分别控制系统功率的输入输出和直流母线电压。最后通过仿真验证所提功率分配方法的有效性和优越性。最后,提出了一种基于功率平衡和储能元件荷电状态(SOC)的能量管理策略。本文采用蓄电池和超级电容的构成的混合储能系统(HESS),通过分析含混合储能的微电网孤岛运行能量供求平衡的机理,并基于蓄电池和超级电容的荷电状态,根据提出的功率管理算法,提出了一种微电网孤岛运行时的能量管理策略对混合储能单元和光伏电源进行能量管理,以维持微电网孤岛运行时的能量和功率平衡,保证电能质量和负荷需求,并优化蓄电池充放电,延长其使用寿命。通过Matlab/Simulink对所提出的能量管理策略进行仿真验证,仿真结果表明本文所提出的能量管理策略在各种运行状态下,均能通过各变换器有效的控制能量流动,同时实现了系统在个运行状态的平滑切换。
[Abstract]:With the wide application of distributed power sources, such as wind and solar energy, and the microgrid, the intermittent nature of distributed power generation, The randomness and load fluctuation have more and more influence on the power quality and stability of microgrid. The energy storage device can restrain the power fluctuation to a certain extent. However, a single energy storage device can not meet the requirements of both power and energy at the same time. The hybrid energy storage system composed of super capacitor and battery can achieve the power balance and improve the power quality of the microgrid. In order to improve the reliability of power supply, this paper takes the photovoltaic microgrid system as the research object, considers the complementary characteristics of battery and super capacitor, and studies the energy management strategy of its microgrid. Firstly, the topology structure of photovoltaic microgrid is analyzed. The equivalent model of photovoltaic unit is proposed. The characteristics of photovoltaic cell are analyzed, and the maximum power point tracking MPPT control is used for photovoltaic cell unit. In order to realize the maximum power and variable power output, the operating characteristics and output characteristics of battery and super capacitor are analyzed, and the equivalent models are established respectively. Then, the design of hybrid energy storage element converter is analyzed. The structure and principle of the bidirectional DC/DC converter are discussed, and the parameters of the converter are designed. This paper discusses several connection modes of two kinds of energy storage elements in hybrid energy storage, analyzes their advantages and disadvantages, determines that the hybrid energy storage adopts active connection method, and analyzes and compares various mixed energy storage power distribution methods. In this paper, a power allocation method based on charge state and independent of frequency is proposed, and then a converter based bipolar converter structure is proposed. The battery and super capacitor adopt different control strategies to control the power input and output of the system and DC bus voltage respectively. Finally, the effectiveness and superiority of the proposed power allocation method are verified by simulation. Finally, This paper presents an energy management strategy based on power balance and the charge state of energy storage elements (SOC). In this paper, a hybrid energy storage system composed of batteries and super capacitors is used to analyze the isolated island operation energy of microgrid with mixed energy storage. The mechanism of balance between supply and demand, Based on the charging state of storage battery and super capacitor and according to the proposed power management algorithm, an energy management strategy for hybrid energy storage unit and photovoltaic power supply is proposed. In order to maintain the energy and power balance, ensure the power quality and load demand, optimize battery charge and discharge and prolong its service life, the proposed energy management strategy is simulated by Matlab/Simulink. The simulation results show that the proposed energy management strategy can effectively control the energy flow through the converters in various operating states, and the smooth switching of the system in each running state can be realized at the same time.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM727;TM53;TM912

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