单相光伏并网逆变器及其控制研究

发布时间：2018-04-17 12:50

本文选题：光伏并网逆变器 + 两级结构　；参考：《辽宁工业大学》2014年硕士论文

【摘要】：随着化石能源的日益匮乏，电力供应的紧张，生态环境的恶化，可再生能源的利用势在必行。太阳能作为绿色新能源得到广泛应用，光伏发电成为太阳能利用的重要方式。而光伏并网逆变器又是并网光伏发电系统的关键部件，因此对其研究显得越来越重要。本文研究了光伏并网逆变器的目的和意义，介绍国内外研究现状，给出了光伏并网的要求。研究了光伏发电系统结构和电路拓扑，比较分析各种常用变换电路的优缺点，结合本文系统中小功率的特点，采用典型的两级式非隔离结构，前级DC/DC变换器选用Boost电路，，后级DC/AC变换器采用全桥电路。重点分析了光伏电池工作原理和等效模型，得出了输出特性曲线，然后讨论了常见的MPPT控制方法，针对扰动观察法出现误判现象给出一种基于功率预测的优化改进算法。重点研究了并网控制技术，选用电流电压双闭环控制策略并用MATLAB进行了仿真。针对PI控制不能消除交流量稳态误差，给出双闭环与重复控制复合的控制策略，使光伏系统既有PI控制的快速响应特性又有重复控制优越的稳态性能，实现无静差。
[Abstract]:With the increasing shortage of fossil energy, the shortage of electricity supply and the deterioration of ecological environment, the utilization of renewable energy is imperative.Solar energy as a new green energy is widely used, photovoltaic power generation has become an important way of solar energy utilization.Photovoltaic grid-connected inverter is the key component of grid-connected photovoltaic power generation system, so it is more and more important to study it.In this paper, the purpose and significance of photovoltaic grid-connected inverter are studied, the research status at home and abroad is introduced, and the requirements of photovoltaic grid-connected inverter are given.The structure and circuit topology of photovoltaic power generation system are studied. The advantages and disadvantages of various common conversion circuits are compared and analyzed. Combined with the characteristics of small power in this paper, the typical two-stage non-isolated structure is adopted, and the Boost circuit is used in the former DC/DC converter.The full bridge circuit is used in the rear stage DC/AC converter.The working principle and equivalent model of photovoltaic cell are analyzed emphatically, the output characteristic curve is obtained, then the common MPPT control method is discussed, and an optimized and improved algorithm based on power prediction is proposed to deal with the misjudgment of disturbance observation method.The grid-connected control technology is studied emphatically. The current and voltage double closed loop control strategy is selected and simulated by MATLAB.In view of the fact that Pi control can not eliminate the steady-state error of AC quantity, a compound control strategy of double closed loop and repetitive control is proposed, which makes photovoltaic system have both the fast response characteristics of Pi control and the excellent steady-state performance of repetitive control, so that there is no static error.
【学位授予单位】：辽宁工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464;TM615

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