三电平光伏并网逆变器控制方法研究

发布时间：2018-04-06 00:15

本文选题：三电平光伏并网逆变器　切入点：双闭环PI控制　出处：《浙江大学》2014年硕士论文

【摘要】：世界能源危机和环境污染使得新能源的开发利用变得至关重要。太阳能发电以其高效清洁、储量丰富、分布广泛等优点成为各国政府和科研机构的研究焦点。为了更加高效、广泛的利用光伏电能,实现光伏发电的优质、友好地并网,需要解决的关键问题是光伏并网逆变器的控制策略。传统的光伏并网逆变器主要采用dq坐标系下电压电流双闭环PI控制,但该控制方法存在的路径耦合、积分饱和、谐波抑制能力不足等问题,导致逆变器输出电能质量较差。本文着重研究三相光伏并网逆变器的控制方法,具体包括：1)介绍了光伏并网逆变系统,在深入分析电压电流双闭环PI控制策略的基础上,提出了一种新型的多矢量比例积分控制方法,改善逆变器输出电能质量；2)针对NPC三电平逆变器直流侧中点电位不平衡问题,提出一种新颖的基于扩张状态观测器和非线性PI控制器的中点电位平衡控制方法；3)搭建一套10kW的三相光伏并网发电系统样机,验证了本文所提出的方法的有效性。
[Abstract]:The world energy crisis and environmental pollution makes the development and utilization of new energy has become important. Solar power with its high efficiency and clean, abundant reserves, wide distribution and other advantages has become the research focus of governments and research institutions. In order to be more efficient, widely use of photovoltaic power energy, photovoltaic power generation to achieve high quality, friendly grid, key problems to be solved the control strategy of photovoltaic grid connected inverter.
The traditional PV grid connected inverter mainly adopts voltage and current double closed loop PI control under dq coordinate system. However, the problem of path coupling, integral saturation and harmonic suppression is not good enough, resulting in poor power quality of inverter.
The control method, this paper focuses on the research of the three-phase grid connected photovoltaic inverter includes: 1) the photovoltaic inverter system, based on a thorough analysis of the voltage and current double closed-loop PI control strategy, proposed a new multi vector proportional integral control method to improve the inverter output power quality; 2) for three NPC DC the inverter side neutral point unbalance, this paper proposes a novel neutral point potential control method of ESO and nonlinear controller based on PI; 3) to build a prototype of 10kW three-phase grid connected PV system, verify the effectiveness of the proposed method in this paper.

【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464

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