级联+H+桥型+SVG+功率单元设计及控制策略研究

哈尔滨工业大学工学硕士学位论文
Baidu Nhomakorabea
摘
要
随着人们对电能质量要求的不断提高，柔性交流输电系统（ FACTS）近年 来发展迅速。SVG 作为其中的重要一员，控制性能优越，补偿效果佳，能有效 抑制电压波动与闪变，消除谐波，已经成为 FACTS 装置的研究方向与热点。 本文的研究对象是级联 H 桥型 SVG，与多重化变压器的结构相比，它避免 了价格昂贵、体积大、损耗大以及变压器的铁磁非线性等缺点，同时与其他多 电平结构相比，级联 H 桥型 SVG 的结构简单、所需元器件少、易于实现模块 化设计。本文首先分析了 SVG 的无功补偿原理，然后对常用的两种调制策略进 行仿真分析，最后采用单级倍频 CPS-SPWM 的调制方法，使用一对反相的正弦 调制波与三角载波进行比较，可以使等效开关频率提高 2 N 倍，控制策略包括直 流侧电容电压控制和交流侧控制，直流侧采用有功电压矢量叠加的控制方法， 维持直流电容电压为恒值；交流侧则采用状态反馈解耦控制，能够实现有功电 流和无功电流的完全解耦。仿真结果表明本文所采用的调制策略和控制策略具 有响应快、补偿效果好、直流侧电容电压保持平衡的优点。 其次，对级联 SVG 的功率单元进行了设计。根据功率单元要实现的具体功 能，设计了 IGBT 驱动电路、信号采样电路、开关电源电路、光纤接口电路和 FPGA 的 SPWM 产生电路，同时还分析了主电路的损耗，并设计了散热环节。 最后，通过实验对功率单元的电路功能进行调试。结果表明各部分组成电 路工作正常、 性能良好， 证明本文所设计的功率单元基本达到要求， 为级联 SVG 装置的完成打下了坚实基础。 关键词：级联 H 桥；SVG；单极倍频 CPS-SPWM；状态反馈解耦控制；电容电 压平衡控制；功率单元
硕士学位论文
级联 H 桥型 SVG 功率单元设计 及控制策略研究
THE DESIGN OF POWER CELL OF CASCADED H BRIDGE SVG AND RESEARCH ON CONTROL STRATEGY
苏 健
哈尔滨工业大学 2012 年 7 月
国内图书分类号： TM714 国际图书分类号： 621.3
Candidate: Supervisor: Academic Degree Applied for: Specialty: Affiliation: Date of Defence: Degree-Conferring-Institution:
Su Jian Associate Prof. Guo Haifeng Master of Engineering Power Electronics and Power Drives Dept. of Electrical Engineering July, 2012 Harbin Institute of Technology
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哈尔滨工业大学工学硕士学位论文
目
摘
录
要 ....................................................................................................................... I 论 ......................................................................................................... 1
Abstract .................................................................................................................... II 第1章 绪 1.1 课题背景、研究目的和意义 ......................................................................... 1 1.2 无功补偿装置的发展概况 ............................................................................. 2 1.2.1 晶闸管控制电抗器 (TCR) ........................................................................ 2 1.2.2 晶闸管投切电容器 (TSC) ........................................................................ 2 1.2.3 静止无功发生器 (SVG) ........................................................................... 3 1.3 SVG 的研究现状 ............................................................................................. 5 1.3.1 SVG 拓扑结构的研究现状 ...................................................................... 5 1.3.2 多电平逆变器调制策略的研究现状 ....................................................... 7 1.3.3 SVG 控制策略的研究现状 ...................................................................... 8 1.4 本文的主要研究内容 ..................................................................................... 9 第 2 章 SVG 的基本原理与调制策略分析 ........................................................... 10 2.1 SVG 的基本原理 ........................................................................................... 10 2.2 SVG 的主电路结构 ....................................................................................... 11 2.3 调制策略分析 ............................................................................................... 12 2.3.1 CPS-SPWM 分析 .................................................................................... 12 2.3.2 CPS-SPWM 仿真验证 ............................................................................ 14 2.4 本章小结 ...................................................................................................... 16 第 3 章 SVG 控制策略研究及仿真分析 ............................................................... 17 3.1 SVG 的数学模型 ........................................................................................... 17 3.1.1 基于 abc 坐标系的数学模型 ................................................................. 17 3.1.2 基于 dq0 坐标系的数学模型 ................................................................ 19 3.2 SVG 的控制策略 ........................................................................................... 21 3.2.1 直流侧电容电压控制 ............................................................................ 21 3.2.2 交流侧控制 ............................................................................................ 25 3.3 SVG 的仿真分析 ........................................................................................... 27 3.3.1 开环仿真分析 ........................................................................................ 28 3.3.2 闭环仿真分析 ........................................................................................ 30
Classified Index： TM714 U.D.C.: 621.3
Dissertation for the Master Degree in Engineering THE DESIGN OF POWER CELL OF CASCADED H BRIDGE SVG AND RESEARCH ON CONTROL STRATEGY
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哈尔滨工业大学工学硕士学位论文
Abstract
With the raised requirement of electric power quality, flexible AC transmission system has been rapidly developed in recent years. As one of the important member in it, SVG has already become a hot research topic and direction of FACTS equipments because of its superior control performance and good compensation effect. It can effectively suppress voltage fluctuation, and reduce harmonics. This paper analyzed the cascaded H-bridge SVG which avoids the high cost, huge volume, high loss and transformer ferromagnetic nonlinear caused by multiple of transformer structure and has series of advantages of simple structure, less devices, easy to achive modular design and packaging compared with other multilevel structure. This paper analyzed the basic compensation principle of SVG firstly, then compared and analyzed the two commonly used modulation strategies, finally, chose the unipolar of double frequence CPS-SPWM mode. It will raise the equivalent switching frequency 2N times, with using a pair of inverting modulation wave to compare with the triangle carrier wave. Control strategies include DC side capacitor voltage control and AC side control, active voltage vector superposition control algorithm was applied to DC side to balance the capacitor voltage; the AC side was controlled by state feedback decoupled control, which can achieve decoupling completely of active and reactive power. Simulation result showed that the above methods can achieve fast dynamic response, provide better effect of reactive power compensation, maintain the balance of DC capacitor voltage. Secondly, completed the design of power cell, which in the cascaded SVG. According to the specific functions, which to be achieved in the power cell, this paper designed the driving circuit of IGBT, signal sampling circuit, power supply circuit, optical fiber interface circuit and the SPWM producing circuit of FPGA. Also, analyzed loss and heat dissipation of the main circuit. At last, debugging the functions of the power cell through the experiment. and the result were successful. The power cell designed in this paper is correct. All of these laid a solid foundation for cascaded SVG. Keywords: cascaded H-bridges, SVG, unipolar dual-frequency CPS-SPWM, state feed-back decoupled control, capacitor voltage balancing control, power cell
学校代码： 10213 密级：公开
工学硕士学位论文
级联 H 桥型 SVG 功率单元设计 及控制策略研究
硕 士 研 究 生 ：苏 健 导 师 ：国海峰 副教授
申 请 学 位 ：工学硕士 学 科 ：电力电子与电力传动
所 在 单 位 ：电气工程系 答 辩 日 期 ： 2012 年 7 月 授予学位单位 ：哈尔滨工业大学