A study on the methods of operation of the connected parallel inverters network

博士留学生学位论文

并网逆变器并联运行方法研究

作者姓名 HOANG THI THU GIANG

学科专业 模式识别与智能系统

指导教师 田联房 教 授

王孝洪 副教授

所在学院 自动化科学与工程学院

论 文 提 交 日 期 2015 年 月 日

A study on the methods of operation of the

connected parallel inverters network

A Dissertation Submitted for the Degree of Doctor of Philosophy

Candidate：Hoang Thi Thu Giang

Supervisor：Prof. Tian Lian fang

South China University of Technology

Guangzhou, China

分类号：TM46 学校代号：10561

学 号 ：201212800024

华南理工大学博士学位论文

并网逆变器并联运行方法研究

作者姓名：HOANG THI THU GIANG 指导教师姓名、职称： 田联房 教授

申请学位级别： 博士 学科专业名称： 模式识别与智能系统

研究方向：电力电子控制技术与应用

论文提交日期：2015 年 月 日 论文答辩日期：2015 年 月 日

学位授予单位：华南理工大学 学位授予日期： 年 月 日

答辩委员会成员：张军、毛宗源、皮佑国、罗飞、田联房

主席：

委员：

华南理工大学

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I

摘 要

将三相逆变器并联运行，可大大提高系统的灵活性,使电源系统的体积缩小、重量

减轻，还也可大大减少开关器件的电流应力，从而提高系统的可靠性、降低成本和提高

功率密度。由于可实现冗余供电，逆变电源的并联技术可以实现 N+1 (N=1,2,3….) 冗

余并联运行方式，当系统中任一个模块由于故障而失效时，其余的 N 个模块仍然可以

继续提供 100%负载功率，可以以较小的功率冗余为代价获得容错冗余功率，大大提高

了系统的可靠性。并联冗余控制是实现高可靠性、大功率电源系统的优选方案。因此，

逆变电源并联技术在航空航天、大型计算机供电系统、通讯电源系统和银行电源系统等

对电源可靠性要求较高的领域具有广泛的应用前景。逆变电源的并联控制技术是近年来

电源领域研究的一个热点课题，具有实际应用意义。

控制并联逆变器系统通常使用传统 PID 控制器来控制电流电压。传统的 PID 控制

器设计成熟，控制效果良好，但也存在参数设计不精确，对系统参数变化敏感，其动态

性能和谐波因数往往难以达到要求等不足。分数阶 PID

控制器具有对被控对象的参数

变化具有较强的鲁棒性，其控制效果优于传统的 PID 控制器，且实现难度与传统 PID

相近等优点。本文将分数阶 PID

 控制器替代传统 PID 控制器，研究控制器的设计方

法，并对设计的控制器在相关系统中进行并得到应用和验证。

论文主要研究内容包括以下几点：

1) 分析了课题研究背景和意义，介绍了逆变器及其并联技术技术的发展应用研究

现状。

2） 分析了三相逆变器的拓扑结构、数学模型和控制方法，在此基础上进一步分析

了逆变器并联系统的模型，逆变器并联运行的机理，介绍了各种并联控制方式。

3）分析和研究了 PWM 逆变器直接电流控制方法、双闭环矢量控制原理、PWM 逆

变器的空间矢量算法；引入电流前馈控制方法，设计了 PWM 逆变器的并联系统，并进

行了系统的建模与仿真分析。

4）分析了并联逆变器系统的环流产生机理、环流抑制技术、均流控制技术以及对

输出电压的影响，介绍了常用的几种均流控制方法，在此基础上提出了最大电流自动均

流法，并进行了仿真验证。

5）介绍了分数阶基本理论，包括分数阶微积分定义、分数阶微积分性质、分数阶

微积分的积分变换，分析了分数阶系统典型环节的特性。

II

6）研究了分数阶 PID

 控制器，介绍了分数阶控制器的离散化实现方法，在此基

础上研究了三相 PWM 逆变器分数阶控制系统，设计了 FO-PID 控制器，研究了其参数

整定方法，并分析了各环节特性及其对控制性能的影响。仿真结果分析证明了基于

FO-PID 的直接电流控制能够实现预定的控制效果，网侧电流接近正弦，功率因数单位

化, 而且 FO-PID 控制器对系统参数变化不敏感, 直流侧电压能够快速稳定在给定值，

控制精确，具有更强的鲁棒性。

7）设计了 PWM 逆变器并联系统的硬件平台和软件算法，并进行了相关实验。实

验结果证明，本文设计的系统，系统运行稳定，在谐波因数、功率因数等方面可满足并

联并网系统的要求，同时可以实现冗余运行，提高了系统的安全性和可靠性。

关键词：三相并网逆变器；并联运行；环流；均流；直接电流；最大电流；分数阶 PID



III

ABSTRACT

A study on the methods of operation of the connected parallel inverters network is

significant in control not only for our country but also for China and other countries in the

world. Three phase inverters have become the main power supply systems, such as office

automation, hospital, bank, play an important role in the field of communications, defense.

Parallel inverter technology is a potential market and has great potential, can be studied

extensively and has many specialized applications. Some recent years, one phase parallel

inverter became mature, and 3-phase connected parallel inverter is gradually becoming a new

research focus of the scientific research.

Three phase inverters in parallel can provide electricity with high capacity as well as

backup power, which is an important research direction, is increasingly being recognized in

the inverter control technology. Using parallel inverter enhance the flexibility of the system,

reduce the volume, the size of the system, increasing the quality of the switching process,

improve reliability, increase power density and reduce the cost of production systems system.

Moreover, using inverters connected in parallel may perform redundant power supply,

improve the reliability of the system work. Parallel inverter technology allows pairing parallel

N + 1 modules, so during operation if one module fails, the remaining N modules will

generate sufficient load capacity of 100%, so the cost will be much cheaper than the equipped

with redundant power supply separately, but the reliability of the system is improved.Parallel

inverter control Technology is now the first choice for control systems require high

performance and high reliability. Therefore, parallel inverter technology is now widely

applied in many fields such as core: aviation, power supply for computer, communication

systems, power supply systems for banks , the system resources required to provide quality

and high reliability. Parallel inverter technology is a hot spot for the supply of energy in

recent years, this study is a significant high practical application.

Parallel inverter control system traditionally use PID controller (proportional, integral,

derivative) to control the voltage, the traditional PID controller has reached maturity, the

resulting control good, but the design parameter is not really optimal, very sensitive to the

variation of other parameters in the system, performance and features of the system is

IV

difficult to achieve an optimal level, so that the amount of highly customizable.

This thesis introduce method using fractional PID



controller to replace the traditional

PID controller design parameters for the controller fractional PID



. The controller segment

brought dramatic changes in the past controls, achieve better control that traditional PID

controller is not reached.

Study on the methods of operation of the connected parallel inverters network has been

done in following steps:

1) The first, thesis analyzes the meaning and context of the study subjects, a general

introduction to the current state of development and application of inverter technology, the

current state of technological development driver pairing in parallel inverter China and other

countries around the world.

2) Analysis of the pattern and texture of the 3-phase inverter, inverter control method of

three-phase inverter models in parallel, working principle analysis of parallel inverter,

introduces the control method common parallel inverter.

3) Analysis and method research to directly control current (DCC) PWM inverter,

control principle two close loop analysis method of space vector PWM inverter, analytical

methods feedback current control and analysis methods to directly current control to the

parallel inverter. Using matlab / simulink to setup and simulate system, simulation results

analysis.

4) Analysis of balanced current system paired parallel inverter, current limiting method

when paired parallel inverter, affecting the output voltage of the inverter parallel coupling.

Engineering controls stratospheric parallel inverter, then analyzes some of the stratospheric

control method used in parallel inverter system analysis and control methods are applied in

this thesis is the method automatically current maximum average. Performance is simulated

by Matlab / Simulink and analyze simulation results

5)Referring to the issues in the fractional control, the definition fractional, the nature of

the area fraction, analysis changing methods in fractional control, analyze the characteristics

of the stages typical volume fraction.

6) Research fractional PID



controller, introduce some approximate analytical

methods of fractional controller, then design the fractional controller for 3-phase inverter

V

system, designed adapters FO-PID controller and its features, analysis and setting the

parameters of the system, through the FO-PID control voltage is stable at a certain value, the

voltage is kept constant even even when the load changes, the grid fluctuations or other

parameters of the system change. Ensuring the performance of three-phase inverter and the

majority of the damage reduction. Simulation results and experiments have demonstrated that

the use of FO-PID control method with direct current control to achieve the results desired

control, the grid current is very close to sinusoidal, power factor is high, moreover FO-PID

controller is not sensitive to changes in the parameters of the system, the DC voltage stability

quickly at a certain value, and the sharp correction and more accurate.

7) Finally, thesis designs main power circuit and locked loop system design experiments

paired parallel inverter (including hardware and software applications), through the table

experiments , analysis of experimental results and draw conclusions: experimental results

have proved the thesis system design reasonable structure, precise control, efficient,

results-driven requirements, meet the requirements of the grid, the efficiency of the system is

improved, and has the effect of inhibiting the appearance of harmonics, grid quality is not

affected, reducing heating systems, safety is enhanced, reduced maintenance workload,

valuable practical application high structure was renovated parallel system, creating favorable

conditions for real life production, reduce waste and conserve natural resources.

Keywords: PWM rectifiers; inverters in parallel ; Direct Current Control, balanced current;

Fractional- order PID

 Controller.

VI

目 录

摘 要................................................................................................................................ I

第一章 绪 论.................................................................................................................. 1

1.1 课题研究背景和意义 ...................................................................................................... 1

1.1.1 课题研究的背景........................................................................................................ 1

1.1.2 课题研究的意义........................................................................................................ 2

1.2.逆变技术的发展和应用 .................................................................................................. 3

1.2.1 逆变技术的发展........................................................................................................ 3

1.2.2 逆变技术的应用....................................................................................................... 4

1.3 中国和其他国家并联逆变技术的现状与发展 .............................................................. 6

1.4 本文主要研究内容和工作 .............................................................................................. 8

第二章 逆变器并联系统模型与工作原理....................................................................... 11

2.1 引言 ................................................................................................................................ 11

2.2 三相逆变器的模型分析 ................................................................................................ 11

2.2.1 三相逆变器 PWM 拓扑结构................................................................................... 12

2.2.2 三相 PWM 逆变器的控制方法............................................................................... 17

2.3 并网逆变器并联系统的模型分析 ................................................................................ 18

2.3.1 逆变器并联拓扑...................................................................................................... 18

2.3.2.逆变器并联运行的原理与分析.............................................................................. 19

2.4 各种并联控制方式 ........................................................................................................ 21

2.4.1 外特性下垂并联控制法.......................................................................................... 21

2.4.2.主从并联控制法...................................................................................................... 23

2.4.3 最大电流并联控制法.............................................................................................. 25

2.5 小结 ................................................................................................................................ 26

第三章 并网 PWM 逆变器直接电流控制方法................................................................ 27

3.1 引言 ................................................................................................................................ 27

3.2 双闭环矢量控制原理与分析 ........................................................................................ 27

VII

3.2.1 直接电流控制方法.................................................................................................. 27

3.2.2 双闭环控制结构...................................................................................................... 28

3.3 PWM 逆变器的空间矢量算法....................................................................................... 31

3.4 基于电流前馈控制方法研究 ........................................................................................ 33

3.5 重复控制的 PI 控制器 ................................................................................................... 35

3.5.1 重复控制系统结构................................................................................................. 36

3.5.2 PWM 逆变器电流重复控制器设计........................................................................ 38

3.5.3 电流环 PI 控制器和重复控制器复合控制............................................................ 40

3.6 并网逆变器 PWM 并联的直接电流控制设计与研究 ................................................. 40

3.7 仿真与分析 .................................................................................................................... 44

3.8 小结 ................................................................................................................................ 49

第四章 并网逆变器并联系统的环流抑制与均流技术.................................................... 50

4.1 引言 ................................................................................................................................ 50

4.2 并联逆变器系统的环流分析 ........................................................................................ 50

4.2.1.并联系统环流的基本概念...................................................................................... 50

4.2.2 功率偏差与环流...................................................................................................... 53

4.2.3 并网逆变器并联环流抑制技术.............................................................................. 55

4.3 并联逆变器对输出电压的影响 .................................................................................... 59

4.4 并网逆变器并联均流控制技术 .................................................................................... 60

4.4.1 均流概念.................................................................................................................. 60

4.4.2 并联均流的原理...................................................................................................... 61

4.4.3 并联运行的均流方法.............................................................................................. 62

4.5 仿真结果 ........................................................................................................................ 67

4.6 小结 ................................................................................................................................ 70

第五章 分数阶 PID

控制理论研究及仿真分析 ............................................................. 71

5.1 引言 ................................................................................................................................71

5.2 分数阶微积分定义 ........................................................................................................71

5.3 分数阶微积分定义间的关系 ........................................................................................ 72

5.4 分数阶微积分性质 ........................................................................................................ 73

VIII

5.5 分数阶微积分的积分变换 ............................................................................................ 73

5.6 分数阶典型环节的特性研究 ........................................................................................ 74

5.6.1 分数阶积分环节...................................................................................................... 74

5.6.2 分数阶微分环节...................................................................................................... 76

5.6.3 分数阶微积分环节.................................................................................................. 78

5.6.4 分数阶比例积分环节.............................................................................................. 80

5.6.5 分数阶比例微分环节.............................................................................................. 82

5.6.6 分数阶 PI

D

 环节 ................................................................................................. 84

5.8 小结 ................................................................................................................................ 85

第六章 分数阶 PID

 控制器在 PWM 逆变器中的应用研究 ......................................... 86

6.1 引言 ................................................................................................................................ 86

6.2 分数阶 PI

D

 控制器 ..................................................................................................... 86

6.3 分数阶控制器的离散化实现 ........................................................................................ 88

6.3.1 直接离散化.............................................................................................................. 88

6.3.2 间接离散化.............................................................................................................. 90

6.4 基于分数阶 PI

D

 控制器研究 ..................................................................................... 90

6.4.1 三相 PWM 逆变器分数阶控制系统....................................................................... 90

6.4.2 分数阶 PID 控制器的设计 ..................................................................................... 93

6.4.3 仿真结果及分析...................................................................................................... 96

6.5 小结 .............................................................................................................................. 102

第七章 并网逆变器系统的实验研究.............................................................................103

7.1 引言 .............................................................................................................................. 103

7.2 主电路参数与锁相环设计 .......................................................................................... 103

7.2.1 交流电感值设计.................................................................................................... 103

7.2.2 直流母线电压值设计............................................................................................ 105

7.2.3 直流母线电容值的设计........................................................................................ 105

7.2.4 锁相环设计............................................................................................................ 106

7.3 PWM 逆变器并联系统的实验设计............................................................................. 108

7.3.1PWM 逆变器控制电路硬件设计........................................................................... 108

IX

7.3.2PWM 逆变器主电路设计....................................................................................... 116

7.3.3 软件设计流程........................................................................................................ 120

7.4 实验结果与分析 .......................................................................................................... 122

7.4.1 整体平台图............................................................................................................ 122

7.4.2 实验结果及波形分析 ............................................................................................... 123

7.5 小结 .............................................................................................................................. 131

结论与展望.....................................................................................................................132

8.1 全文工作总结 .............................................................................................................. 132

8.2 进一步工作展望 .......................................................................................................... 133

参考文献 ........................................................................................................................135

致 谢............................................................................................................................148

X

CONTENT

ABSTRACTS I

Chapter 1 Introduction 1

1.1 research background and significance 1

1.1.1 Background research project 1

1.1.2. Significance of research 2

1.2. The development and application of inverter technology 3

1.2.1 Development inverter technology 3

1.2.2 Application of inverter technology 4

1.3 Status and Development of China and other countries in parallel inverter technology 6

1.4. The main research and work 8

Chapter 2 Inverter parallel system model and analysis of working principle 11

2.1 Introduction 11

2.2 Model of the three-phase inverter 11

2.2.1 Three-phase PWM inverter topology 12

2.2.2 The control method of three-phase PWM inverter 17

2.3 The model of the inverter parallel system analysis 18

2.3.1 inverter parallel topology 18

2.3.2 The principle of parallel operation of the inverter and analysis 19

2.4 Various parallel control mode 21

2.4.1 Parallel droop control method 21

2.4.2 master-slave parallel control method 23

2.4.3 Maximum current parallel control method 25

2.5 Summary 26

Chapter 3 PWM inverter direct current control method 27

3.1 Introduction 27

3.2 pairs of closed-loop vector control theory and analysis 44

3.2.1 Direct Current Control Method 27

XI

3.2.2 The dual-loop control structure 28

3.3. PWM inverter space vector algorithm 31

3.4 Based on current research before feedforward control method 34

3.5 repetitive control PI controller 36

3.5.1 repetitive control system architecture 36

3.5.2 PWM inverter current repetitive controller design 38

3.5.3 current loop PI controller and the repetitive controller complex control 40

3.6 Design and Research direct current shunt PWM inverter control 40

3.7 Simulation and Analysis 44

3.8 Summary 49

Chapter 4 Switching inverters in parallel circulation are streaming technology 50

4.1 Introduction 50

4.2 Circulation analysis of parallel inverter system 50

4.2.1. The basic concept of the parallel system circulation 50

4.2.2 power deviation and Circulation 53

4.2.3 parallel inverter circulation suppression 55

4.3 Parallel influence on the output voltage of the inverter 60

4.4 Inverter Parallel flow control technology 61

4.4.1 Current concepts 61

4.4.2 Parallel flow principle 61

4.4.3 Current methods for parallel operation 62

4.5. The simulation results 68

4.6 Summary 70

Chapter 5 Fractional PID



control theory and simulation analysis 71

5.1 Introduction 71

5.2 Fractional Calculus definition 71

5.3 Fractional Calculus relationship between definitions 72

5.4 Fractional Calculus nature 73

5.5 Fractional calculus integral transformation 73