论文总字数：42406字

摘 要

16012407 刘瑶

指导教师 赵剑锋

摘要正文：当今，我国正向工业大国的目标飞速迈进，但随之而来的环境污染问题也是不容忽视的。等离子体技术被广泛应用于工业废气废水处理之中，是环境保护事业的一个里程碑。本文旨在为用于工业生产的等离子体污水处理高压电源选择一种高功率因数整流器，在多电平PWM整流技术蓬勃发展的背景下，本文讨论了一系列比较常见的三电平PFC拓扑结构，最终选择了开关器件少、开关器件电压应力低、可靠性高、无死区的三相三电平三开关boost型PWM整流器，即VIENNA整流器作为研究对象。

本文根据VIENNA整流器在dq同步旋转坐标系下的数学模型，设计了一个基于空间矢量调制的双闭环控制系统。首先，对网侧电流进行前馈解耦，通过电压外环控制输出直流电压稳定在期望值，电流内环控制网侧输入三相电流正弦化且与三相相电压同相位。然后将生成的参考电压矢量转换到两相静止坐标系中输入至PWM控制器，PWM控制器采用空间矢量调制算法为三相桥臂分配脉冲。本设计中三电平空间矢量调制算法来源于对VIENNA整流器工作原理的分析。VIENNA整流器的三个桥臂对应25个基准电压矢量，按模值不同可分为大矢量、中矢量、小矢量和零矢量。这25个矢量的顶点组成了一个正六边形，并将空间划分为了36个小区域。本文根据参考电压矢量与𝞪轴的夹角和调制比计算出参考电压矢量所在区域，遵循最近三矢量原则选定合成参考电压矢量所用的基准矢量，按照伏秒平衡原理计算出这三个基准矢量的作用时间，采用负七段式矢量合成方法确定三个基准矢量的作用顺序，进行作用时间的分配，进行目标参考矢量的合成。本文搭建SIMULINK仿真模型验证了上述控制策略，仿真结果显示电路各项指标均达到技术指标。

本文还对VIENNA整流器的中性点不平衡问题进行了分析，并通过SIMULINK仿真验证了调节正负小矢量作用时间以平衡中性点的方法的正确性。另外，作为本文创新点，本文在传统VIENNA整流器L滤波的基础上，提出了采用LCL滤波替换L滤波，对其参数进行了计算，并通过仿真对比，证明了LCL滤波整流器THD更低，整体效果更好。

关键词：多电平整流，VIENNA整流器，SVPWM，中性点平衡， LCL滤波

Abstract

Abstract： Nowadays, China is moving towards to the goal of becoming an industry country, but the problem of environmental pollution is also severe. Plasma technology is widely used in the industrial waste water and gas treatments. It is a milestone of environmental protection. The purpose of this paper is to choose a high power factor rectifier for the Plasma high voltage power supply of is waste water treatment used in industrial production, a series of common three-level PFC topologies are discussed, the final choice is Vienna rectifier, the three-phase three-level three switch boost type PFC topology, which has less switch device, lower switch device voltage stress, higher reliability, and no dead zone.

In this paper, a double closed loop control system based on SVPWM is designed according to the Vienna rectifier model in the DQ synchronous rotating coordinate system. First, the feedforward decoupling is needed. The outer voltage loop is to keep DC output voltage at a desired value, current inner loop is to make input three-phase current a sine wave and at same phase with three-phase voltage. The reference voltage vector is converted into the two-phase stationary coordinate system as the input of the PWM controller, and the space vector modulation algorithm is used in the PWM controller to arrange the pulse. The three bridge-arms of Vienna rectifier are corresponding to 25 reference voltage vector except two invalid state, they can be divided into the large vector, medium vector, small vector and zero vector for their different modulus values. They formed a hexagonal and divided the space to six large areas, and each large area could be divided into six small areas. In this paper, the reference voltage vector region is located according to the reference voltage vector angle and modulation ratio. The three vectors to compose the reference voltage vector are selected by the recent three vector principle. The action time of the three vectors are calculated in accordance with the volt second balance principle. The three basis vector sequence and the allocation of time are determined by negative seven segment vector synthesis method. Thus, the reference voltage vector is well synthesized. In this paper, the SIMULINK simulation model is built to verify the control strategy. The simulation results showed that the indicators of the circuit are all up to the technical specifications.

In this paper, the neutral point unbalance problem of Vienna rectifier are analyzed, and the method to keep neutral point balanced by adjusting the work time of positive and negative small vectors is verified by simulation. In addition, as the innovation point of this paper, LCL filter is put forward as the replacement of L filter, the parameters are calculated and it is verified that the THD of LCL filter rectifier is lower and the overall effect is better by SIMULINK results.

Key words: multilevel PWM rectifier, Vienna rectifier, SVPWM, neutral point balance, LCL filter

目录

摘要 I

Abstract II

目录 III

第一章 绪论 1

1.1课题背景及研究意义 1

1.2国内外研究现状 1

1.2.1等离子体高压电源用整流器 1

1.2.2VIENNA整流器输入电流控制策略 2

1.2.3 VIENNA整流器直流电压控制策略 2

1.2.4 VIENNA整流器调制策略 2

1.2.5 LCL滤波技术 2

1.4三相PFC拓扑结构发展 2

1.4.1三相单开关boost型 3

1.4.2三相六开关boost型 3

1.4.3二极管嵌位三电平型 4

1.4.4三相三电平三开关boost型PFC（VIENNA整流器） 4

1.5本文主要工作 5

第二章 VIENNA整流器工作原理及建模 6

2.1引言 6

2.2VIENNA整流器工作原理 6

2.2.1VIENNA整流器拓扑结构 6

2.2.2VIENNA整流器工作原理及开关状态 6

2.3VIENNA整流器建模分析 11

2.3.1三相静止坐标系下的数学模型 11

2.3.2两相静止坐标系下的数学模型 13

2.3.3同步旋转坐标系下的数学模型 14

2.4本章小结 14

第三章 前馈解耦双闭环空间矢量控制 15

3.1引言 15

3.2前馈解耦双闭环控制策略 15

3.3空间矢量调制 16

3.3.1 VIENNA整流器空间矢量平面 16

3.3.2 矢量所在区域判断 18

3.3.3 矢量作用时间计算 20

3.3.4 矢量作用顺序确定 24

3.4仿真验证 27

3.4.1 仿真结构构建 27

3.4.2 仿真结果分析 34

3.5本章小结 37

第四章 中性点平衡控制分析 38

4.1引言 38

4.2VIENNA整流器中性点不平衡原因分析 38

4.3VIENNA整流器中性点平衡控制方法 39

4.4仿真验证 40

4.5本章小结 40

第五章 LCL滤波在VIENNA整流器中的应用 41

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