基于混合储能的光伏并网功率平抑控制研究

发布时间：2018-01-13 02:15

本文关键词：基于混合储能的光伏并网功率平抑控制研究　出处：《山东大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着化石燃料的日益减少,可再生能源发电发展迅猛,但随之而来的缺陷也暴露无遗。在众多可再生能源中,太阳能的使用范围非常广泛。但光伏发电由于受日照强度、温度等的影响,会产生较大波动的功率,所以在大规模并网技术中仍存在些许问题。本文针对光伏发电因光照强度与温度变化而导致的发电功率波动问题,提出一种储能型光伏并网发电系统,以抑制并网功率的波动。以光伏发电最大功率跟踪和并网逆变控制为基础,引入蓄电池和超级电容器组成的混合储能系统,实现对光伏发电功率削峰填谷、达到平抑功率的效果。首先,本文以单级式光伏并网逆变系统的综合控制策略为研究对象,对光伏阵列数学模型、最大功率点跟踪方法、单级式光伏并网系统拓扑结构及其数学模型等问题进行了系统深入的研究。并提出了一种变步长的最大功率点追踪(MPPT)算法,与定步长的MPPT算法相比,响应速度更快,寻优过程更精确,能够更好地避免因寻找最大功率点而产生的系统振荡。本文针对光伏并网逆变系统的控制策略,提出了采用空间矢量调制(SVPWM)的方法产生触发信号,充分利用该方法的谐波含量低、直流电压利用率高等优势,最终确定基于SVPWM控制的单级式光伏并网系统的综合控制策略。其次,本文通过比较各种储能技术的优缺点,选择了将超级电容器和蓄电池组成混合储能系统,并提出了将混合储能应用于独立光伏发电系统,以优化蓄电池的充放电过程。混合储能系统连接方式有三种,本文采用了一种有源并联方式,即通过功率变换器并联。为了实现储能系统平抑光伏输出功率波动的目标,并提高蓄电池使用寿命,本文采用了一种将并联控制器与充电控制器统一进行控制设计的方法；综合考虑独立光伏系统的容量及外界天气变化影响等因素,针对混合储能系统中的超级电容器和蓄电池两种储能元件进行容量设计,并给出了不同情况下的最优设计方法；最终对提出的混合储能系统的控制策略进行了仿真分析和实验验证。最后,提出了将超级电容器和蓄电池组成的混合储能系统应用于大规模光伏并网系统之中,并确立了基于双向DC-DC变换器的混合储能系统的控制策略。对双向DC-DC变换器设计了不同的工作模式,以改变其功率流向,实现超级电容器与蓄电池的功率流通。本文选题依托于中电普瑞科技有限公司的10kW光伏储能系统并网示范工程,在本文的最后,介绍了该系统组成设备的各项参数、控制策略及监控系统等内容,并通过实际工程数据验证了混合储能平抑光伏功率波动的正确性。
[Abstract]:With the decrease of fossil fuels, renewable energy power generation is developing rapidly, but the following defects are also exposed. In many renewable energy sources. The use of solar energy is very wide, but photovoltaic power generation will have a large fluctuation of power due to the influence of sunshine intensity and temperature. Therefore, there are still some problems in large-scale grid-connected technology. In this paper, a kind of energy storage photovoltaic grid-connected generation system is proposed to deal with the fluctuation of generation power caused by the change of light intensity and temperature. In order to restrain the fluctuation of grid-connected power, based on the maximum power tracking and grid-connected inverter control of photovoltaic generation, a hybrid energy storage system composed of batteries and supercapacitors is introduced to realize peak and valley reduction of photovoltaic power. Achieve the effect of stabilizing power. Firstly, the integrated control strategy of single-stage photovoltaic grid-connected inverter system is studied in this paper. The mathematical model of photovoltaic array and the maximum power point tracking method are studied. The topology and mathematical model of single-stage photovoltaic grid-connected system are studied in detail, and a variable step maximum power point tracking (MPPTT) algorithm is proposed. Compared with the fixed-step MPPT algorithm, the response speed is faster and the optimization process is more accurate. The system oscillation caused by finding the maximum power point can be avoided better. Aiming at the control strategy of photovoltaic grid-connected inverter system, the space vector modulation (SVPWM) method is proposed to generate the trigger signal. Based on the advantages of low harmonic content and high DC voltage utilization, the integrated control strategy of single-stage photovoltaic grid-connected system based on SVPWM control is finally determined. Secondly, by comparing the advantages and disadvantages of various energy storage technologies, a hybrid energy storage system composed of supercapacitors and batteries is selected, and a hybrid energy storage system is proposed for independent photovoltaic power generation systems. In order to optimize the charging and discharging process of the battery, there are three connection modes of the hybrid energy storage system. In this paper, an active shunt mode is used. In order to achieve the goal of suppressing the fluctuation of photovoltaic output power of the energy storage system and to improve the battery service life, the power converter is connected in parallel. In this paper, a control design method of parallel controller and charging controller is adopted. Considering the capacity of the independent photovoltaic system and the influence of the external weather, the capacity of the supercapacitor and the storage battery in the hybrid energy storage system is designed. The optimal design method under different conditions is also given. Finally, the proposed control strategy of hybrid energy storage system is simulated and verified by experiments. Finally, the hybrid energy storage system composed of supercapacitor and battery is applied to large-scale photovoltaic grid-connected system. The control strategy of hybrid energy storage system based on bi-directional DC-DC converter is established. Different operation modes are designed to change the power flow direction of the bi-directional DC-DC converter. Realize the power flow between supercapacitor and battery. This paper is based on the 10kW photovoltaic energy storage system demonstration project of CLP Prey Technology Co., Ltd., at the end of this paper. The parameters, control strategy and monitoring system of the system are introduced, and the correctness of the hybrid energy storage to suppress the photovoltaic power fluctuation is verified by the actual engineering data.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM615

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