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光伏发电逆变并网系统复合控制策略

2017-05-18孟军徐先勇方璐贺西汪沨

湖南大学学报·自然科学版 2017年4期

孟军+徐先勇+方璐+贺西+汪沨

摘 要:研究了一种适用于兼顾无功补偿的微网光伏并网逆变系统,提出一种单相光伏逆变器的复合控制方法.根据单相光伏逆变器的功率平衡原理,推导出光伏逆变器的直流侧二次纹波电压的大小,由此进行校正补偿消除逆变器输出的三次谐波电流.光伏单相并网逆变器的前馈基波调制信号可由其稳态数学模型得出,从而进行输出电流快速前馈控制,然后利用无差拍控制器来实现输出电流的闭环控制,从而形成了前馈+反馈的复合控制方法,可以实现单相逆变器输出电流的快速、无差跟踪.实验和仿真结果表明了本文所提出的复合控制方法能够提高光伏并网逆变器的工作性能,并改善微网的电能质量.

关键词:微网;复合控制;有功功率控制;无功功率控制;光伏发电

中图分类号:TK514 文献标志码:A

Hybrid Control Strategy of Photovoltaic Generation Inverter Grid-connected Operating System

MENG Jun1,2, XU Xianyong2, FANG Lu3, HE Xi3, WANG Feng3

(1. Business School, Central South University, Changsha 410083, China;

2.Hunan Electric Power Company, Changsha 410007, China;

3.Modern Engineering Training Center, Hunan University, Changsha 410082, China)

Abstract:A kind of micro-grid photovoltaic inverter system considering the reactive power compensation was studied, and a compound control method for photovoltaic inverter was proposed. According to the power balance principle of single-phase photovoltaic inverter, the value of dc-side second-ripple voltage was deduced. Thus, it can modify and eliminate the output third harmonic current of photovoltaic inverter. Based on the steady-state mathematical model of single-phase inverter, the feed forward fundamental modulation signal of the inverter can be calculated, and then the output current closed-loop control can be realized by using deadbeat controller. As a result, the feed forward-feedback compound control method was formed, which can achieve fast and zero-error tracking of output current. The experiment and simulation results show that the proposed compound control method can effectively improve the dynamic performance of single-phase and perfect the power quality of distribution grid.

Key words:micro grid; hybrid control strategy; active power control; reactive power control; photovoltaic generation

隨着全球能源发展战略的变化,开发和利用绿色能源已经成为世界各国关注的焦点.太阳能作为一种可持续发展的绿色能源,其开发和利用已经引起世界各国和研究机构的高度重视,能源专家和工程技术人员对其开发利用进行了大量研究.建立光伏分布式发电系统,有助于为用户提供丰富的绿色能源[1-2].同时也是实现我国节能减排和治理环境污染以及解决化石能源短缺的重要举措[3-5].

由光伏发电系统的原理和构成可知,光伏电池输出为直流电,必须通过逆变器转换为交流电才能并……

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