摘 要

近年来，由于世界性能源危机、人们日益增长的环保意识和政府的大力支持，光伏产业发展越来越迅速，这时就出现了光伏系统发出的电能在用户使用剩余之后并入电网的情况。本文主要针对光伏并网系统进行模拟仿真，其中采用了光伏电池的最大功率控制、锁相环环节、三相对称静止abc坐标系到两相运动坐标系dq的坐标转换、并网PQ控制、逆变器SPWM控制。

第一章简述了光伏并网系统的背景和研讨的意义，紧接着介绍了德国、日本和我国的光伏产业的发展现状和本课题使用软件PSCAD的适用范围和优势。

第二章详细解释产生光伏发电现象的原因，即固体半导体具有显著的光伏效应。之后通过公式定量的介绍了温度、光照强度对光伏电池的影响以及对光伏电池进行建模。设计电路仿真伏安特性和电压-功率曲线，通过仿真发现光伏电池的电压-功率曲线有且仅有一个最大功率点。希望光伏阵列的电能转化效率最高，提出了最大功率跟踪控制，主要论述了固定电压跟踪法和扰动观察法的原理，将方法应用在中加入直流-直流换流电路的光伏系统中，并且在软件中用不同的方法实现。

第三章讲述了光伏系统的并网控制，阐述了进行坐标转换必要性，提出将三相静止坐标系下实时变化交流量转为两相旋转坐标系下的直流量进行控制。基于电网电压定向的坐标变换是为了完成有功和无功功率的解耦的目标，使得有功功率只由电流的d轴分量控制，无功功率只由电流的q轴分量控制，有功无功就可以独立的控制。锁相环跟踪电网电压与平衡节点的角度就可以实现基于电网电压定向的坐标变换。通过基尔霍夫定律列出逆变器电压电流等式进行坐标变化，引入PI控制器，进行无静差控制。最后一步对逆变器的开关管进行SPWM控制，通过滤波器滤出谐波，然后并入电网。

第四章主要是在PSCAD中进行光伏并网系统的建模仿真以及分析，将第三章中所讲述的理论在模型仿真中实现。

第五章总结了本文所做的主要工作和理论，提出了将光伏并网系统当成负载接入配电网联络线合环，钻研分布式电源（光伏系统）接入配电网末端后对配电网合环电流的影响的瞻望。

关键词：光伏发电;光伏最大功率跟踪控制;光伏并网控制;PSCAD建模

Abstract

Recently, due to the global energy crisis, people's growing awareness of environmental protection and the government's strong support, photovoltaic industry is developing more and more quickly, then there is the situation that the photovoltaic system issued by the user after the use of, the remaining power put into grid . The purpose of this article is to discuss the simulation of photovoltaic grid-connected system, which uses the maximum power control of the photovoltaic cell, the phase-locked loop, the three-phase symmetric static abc coordinate system to the two-phase motion coordinate system dq coordinate transformation, inverter SPWM control.

The first chapter briefly narrates the background and the significance of the PV grid-connected system, and then introduces the development of photovoltaic industry in Germany, Japan and China, and the scope and advantages of using the software PSCAD.

The second chapter explains in detail the cause of the phenomenon of photovoltaic power generation, that is solid-state semiconductor has a significant photovoltaic effect. Then the paper recounts the influence of temperature and light intensity on the photovoltaic cells which are described quantitatively by the formula and models of the photovoltaic cells. The article designs the circuit which could simulate the volt-ampere characteristic and the voltage-power curve, and the simulation results show that the voltage-power curve of the photovoltaic cell has only one maximum power point. It is hoped that the energy conversion efficiency of PV arrays is the highest, and the maximum power tracking control is proposed. The principle of fixed voltage tracking method and perturbation observation method is mainly discussed. The method is applied to the photovoltaic system with DC-DC converter circuit in a different way to achieve.

The third chapter describes the grid control of the PV system, and expounds the necessity of coordinate transformation. It is proposed that the real-time change of the three-phase static coordinate system can be converted into the direct current flow in the two-phase rotating coordinate system. Based on the grid voltage orientation of the coordinate transformation is to complete the active and reactive power decoupling target, making the active power only by the current d-axis component control, reactive power only by the current q-axis component control, active and reactive can Independent control. The phase-locked loop tracks the grid voltage and the angle of the equilibrium node to achieve coordinate transformation based on grid voltage orientation. Through the Kirchhoff law listed in the inverter voltage and current equation for coordinate changes, the introduction of PI controller whose control is accurate. The last step of the system is inverter SPWM control, then filter out the harmonics of the output, and incorporation into the grid. Last but not the least, simulate of PV grid-connected system.

The fourth chapter is mainly in PSCAD in the PV grid-connected system modeling and simulation and analysis, the theory described in Chapter 3 in the model simulation to achieve.

The fifth chapter summarizes the main work and theory of this paper, and puts forward that the PV grid-connected system is regarded as a load-connected distribution network connection ring, and consider the expectation of the influence of the distributed power supply (PV system) on the distribution loop current after distribution of the end of the distribution network.

Key words: Photovoltaic power generation; Photovoltaic maximum power tracking control; PV grid-connected control; PSCAD modeling

目 录

摘 要 I

Abstract II

第1章 绪论 1

1.1 研究背景 1

1.2 国内外光伏发电产业发展现状 1

1.3 PSCAD软件介绍 2

1.4 本文主要研究内容 3

第2章 光伏电池最大功率点跟踪控制技术 4

2.1 光伏电池工作原理 4

2.2 光伏电池特性 5

2.2.1 输入输出特性 5

2.2.2 光照强度特性 5

2.2.3 温度特性 6

2.2.4 PSCAD中光伏电池等效电路 6

2.3 光伏并网系统 12

2.3.1 升压斩波电路 13

2.3.2 参数设置 14

2.4 最大功率点跟踪控制 15

2.4.1 固定电压跟踪法 16

2.4.2 固定电压跟踪法控制策略 16

2.4.3 扰动观察法 17

2.4.4 扰动观察法控制策略 18

2.5 本章小结 24

第3章 光伏系统并网控制 25

3.1 坐标变换 25

3.2 锁相环 27

3.2.1 PSCAD中锁相环 28

3.3 并网PQ控制 30

3.4 SPWM控制 33

3.5 本章小结 34

第4章 仿真分析 35

4.1 SPWM仿真实现 35

4.2 系统仿真及分析 36

4.3 本章小结 41

第5章 总结与展望 42

参考文献 43

致谢 44

第1章 绪论

1.1 研究背景

在1900到2013的113年期间，世界人口从16亿到72亿，增加了4.5倍，而能源消耗却增加了18倍。全世界石油、煤炭、天然气这些化石能源在世界能源消费结构中所占的比例合计87%以上，我国更是达到92%（2013年）。大量使用以煤炭为首的化石能源，会产生大量一氧化碳(CO)、二氧化碳()、二氧化硫()、氮的氧化物()等气体，导致大气污染、温室效应、酸雨，危害环境和侵害人体身体健康。如果不发展代替能源，按照当前的消耗情况推算，21世纪又会面临新的能源危机^[1]。

不论是日渐严重的环境污染，还是即将面临的能源危机，都制约着社会的发展，同时也在严肃的告诫人们，化石燃料并不是无限的，自然的自我恢复能力也是有限的，人类已经在慢慢意识到并逐步发展可再生能源的产业。可再生能源指的是能够永远使用的能源，源于大自然，包含太阳能、风能等，取之无禁、用之不竭，并且对环境友好。相比较于别的几种可再生清洁能源^[2]，太阳能由于突出的特征和优点，被认为非常有发展前景。太阳能既可免费利用，又无需运输，使用方便，对环境友好，是人类最轻易获得的自然资源之一。其中，作为太阳能运用的主要路径，光伏发电技术也得到了持续的发展。