两级三相式光伏并网发电系统控制策略的研究

发布时间：2018-10-11 14:08

【摘要】：能源的有效利用是人类社会文明进步的重要标志,大规模使用传统的煤炭、石油等非再生能源,不仅造成了环境的严重污染,而且致使能源的日近枯竭。太阳能是无穷无尽,源源不断的环保能源。为了缓解能源危机、减轻环境污染,大范围高效率的利用太阳能便是行之有效的措施之一。因此,世界各国纷纷把目光投向了光伏并网发电系统的研究上。首先搭建了光伏电池仿真模型,合理简化最大功率点跟踪(MPPT)算法,阐述了传统MPPT控制方法原理,并对比分析各种改进算法原理,提出一种基于电压自寻优扰动的光伏MPPT算法,仿真结果表明改进算法具有追踪速度快、准确率高的优点;然后对光伏并网逆变器的数学模型进行推导,并根据瞬时功率理论,进一步建立了两级三相式光伏逆变器拓扑结构的功率数学模型,将基于电网侧无电压传感器的直接功率控制(V-DPC)策略应用于三相光伏并网系统中,搭建MATLAB/SIMULINK并网仿真模型,仿真与实验结果验证了控制方案切实可行,并网波形好,直流电压利用率高;最后再对孤岛检测方法的原理和分类进行介绍,将基于模糊PID控制的主动移相式(APS)孤岛检测法应用到光伏并网发电系统中,仿真实验结果证明了基于模糊PID的APS孤岛检测控制策略不仅能更快的检测出孤岛,而且能够有效地减小系统正常运行时的THD。本文从如何提高光伏并网发电系统稳定性的角度出发,对两级三相式光伏并网发电系统的控制策略展开一系列研究,通过MATLAB/SIMULINK仿真环境,在仿真试验中证明该光伏并网系统的最大功率点追踪精度高,并网波形及孤岛检测技术也达到了国家规定的技术标准。
[Abstract]:The effective utilization of energy is an important symbol of the progress of human civilization. The large-scale use of traditional non-renewable energy, such as coal and petroleum, not only causes serious environmental pollution, but also results in the depletion of energy day by day. Solar energy is an endless, continuous source of environmental energy. In order to alleviate the energy crisis and reduce environmental pollution, the efficient use of solar energy is one of the effective measures. Therefore, countries all over the world have turned their attention to the research of photovoltaic grid-connected power generation system. Firstly, the photovoltaic cell simulation model is built, the maximum power point tracking (MPPT) algorithm is simplified reasonably, the principle of traditional MPPT control method is expounded, and various improved algorithms are compared and analyzed, and a photovoltaic MPPT algorithm based on voltage self-optimizing disturbance is proposed. The simulation results show that the improved algorithm has the advantages of high tracking speed and high accuracy, and then the mathematical model of photovoltaic grid-connected inverter is derived and based on the instantaneous power theory, Furthermore, the power mathematical model of the topology of two-stage three-phase photovoltaic inverter is established. The direct power control (V-DPC) strategy based on voltage sensorless is applied to the three-phase photovoltaic grid-connected system, and the simulation model of MATLAB/SIMULINK grid-connected is built. The simulation and experimental results show that the control scheme is feasible, the waveform of grid connection is good, the utilization rate of DC voltage is high. Finally, the principle and classification of islanding detection methods are introduced. The active phase shift (APS) islanding detection method based on fuzzy PID control is applied to photovoltaic grid-connected generation system. The simulation results show that the APS islanding detection control strategy based on fuzzy PID can detect the isolated islands more quickly. And it can effectively reduce the THD. when the system is running normally. In this paper, from the point of view of how to improve the stability of photovoltaic grid-connected generation system, a series of research on the control strategy of two-stage three-phase photovoltaic grid-connected generation system is carried out, and the simulation environment of MATLAB/SIMULINK is adopted. The simulation results show that the maximum power point tracking accuracy of the photovoltaic grid-connected system is high, and the grid-connected waveform and islanding detection technology also meet the national standard.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM615

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