大型并网光伏电站主动谐波抑制方法研究

发布时间：2018-03-18 16:05

本文选题：大型并网光伏电站　切入点：并网逆变器　出处：《沈阳工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：大型并网光伏电站具有集中利用太阳能的优势,有利于扩大光伏发电规模,成为近年来新能源发电的重点规划和建设目标。随着大型光伏电站并网容量的加大,大多数国家都建立了严格的并网标准来确保电网安全,故为确保光伏电站的安全稳定运行,研究光伏电站并网电能质量就显得尤为重要。本文在开展光伏并网逆变器基础研究时,在其理论分析和仿真的基础上,对大型并网光伏电站谐波检测方法和谐波抑制策略开展了研究,具体内容如下:(1)并网逆变器谐波机理研究本文以常用三相光伏并网逆变器作为研究对象,对其基本结构和工作原理进行了分析,在此基础上,分析了并网光伏电站两种常用并网控制策略,并验证了该并网控制方法对电网背景谐波的扰动抑制效果可靠性不高;最后,针对SPWM调制模式下的逆变器输出谐波影响因素进行了研究,并总结其输出谐波分布概率。(2)谐波电流检测方法研究本文基于现阶段最具代表性的瞬时无功谐波检测法和傅里叶谐波检测方法,对其检测原理和适用范围进行了分析研究,针对傅里叶变换实时性较差、瞬时无功功率检测动态响应差和检测范围较小的缺陷,本文研究了人工神经网络(ANN)模型下的自适应谐波检测算法,对其基本检测原理与数学模型进行了分析,仿真结果验证,该方法具有较好的实时性和动态性,并能检测出任意指定次数谐波。(3)并网光伏电站谐波抑制方法研究本文为提高光伏电站并网电能质量,减小并网电流谐波含量,基于闭环系统传递函数的输出阻抗特性,深入分析了电网电压前馈控制、多谐振控制的谐波抑制机理及抑制效果;在此基础上,研究了基于电网电压前馈和多谐振控制相结合的组合谐波抑制方法;理论分析和仿真结果,均验证了组合谐波抑制策略的谐波抑制效果远比现有谐波抑制策略能更好地改善光伏电站并网电能质量。
[Abstract]:Large-scale grid-connected photovoltaic power plants have the advantages of concentrated utilization of solar energy, which is conducive to expand the scale of photovoltaic power generation and become the key planning and construction target of new energy generation in recent years. With the increase of grid-connected capacity of large-scale photovoltaic power plants, Most countries have established strict grid-connected standards to ensure grid safety, so to ensure the safe and stable operation of photovoltaic power plants, It is particularly important to study the grid-connected power quality of photovoltaic power plants. In this paper, the theoretical analysis and simulation of photovoltaic grid-connected inverters are carried out. The harmonic detection method and harmonic suppression strategy of large-scale grid-connected photovoltaic power station are studied. The main contents are as follows: 1) the harmonic mechanism of grid-connected inverter is studied in this paper, the commonly used three-phase photovoltaic grid-connected inverter is taken as the research object. Based on the analysis of its basic structure and working principle, two common grid-connected control strategies of grid-connected photovoltaic power station are analyzed, and the reliability of the grid-connected control method to restrain the background harmonic disturbance is not high. The factors affecting the output harmonics of the inverter in SPWM modulation mode are studied. In this paper, based on the most representative instantaneous reactive harmonic detection method and Fourier harmonic detection method, the detection principle and applicable range are analyzed and studied. Aiming at the shortcomings of poor real-time performance of Fourier transform, poor dynamic response of instantaneous reactive power detection and small detection range, an adaptive harmonic detection algorithm based on artificial neural network (Ann) model is studied in this paper. The basic detection principle and mathematical model are analyzed, and the simulation results show that the method has good real-time and dynamic characteristics. The harmonic suppression method of grid-connected photovoltaic power station is studied in this paper. In order to improve the power quality of grid-connected photovoltaic power station and reduce the harmonic content of grid-connected current, the output impedance characteristic based on the transfer function of closed-loop system is studied. The harmonic suppression mechanism and effect of voltage feedforward control and multi-resonance control are deeply analyzed, and the combined harmonic suppression method based on the combination of voltage feedforward and multi-resonance control is studied. The theoretical analysis and simulation results show that the harmonic suppression effect of the combined harmonic suppression strategy is much better than that of the existing harmonic suppression strategy.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM615

【参考文献】