软开关技术在变频器中的应用

文档编号:JD300       文档字数:31061,页数:65

摘 要：21世纪的电力电子产品应该是无公害或低公害的“绿色” 产品。因此如何在变频应用领域实现这一目标具有十分重要的现实意义。本研究课题的目标是三相软开关变频器DC直流环节的并联谐振，实现逆变桥上每个功率开关器件以零电压方式开通，达到软开关的目的。并以TI公司的TMS320LF2407型DSP为核心构成整个系统的控制电路，进行异步电机新型控制策略的研究。
文档首先阐述了SAPWM模式的原理以及DC—AC逆变器中的软开关谐振变换技术，重点讨论了本研究的软开关拓扑结构及其控制策略，并对其工作过程中的9个模式作了详细的数学解析。本研究的实验装置包括主电路和控制电路。主电路采用IMP模块来实现DC—AC逆变；控制电路是以TMS320LF2407 DSP评估板为核心扩展出的印刷线路板，主要生成各种触发信号、保护信号以及实现变频器的部分功能。在逆变器正常工作的基础上对中间谐振环节，即零电压开关电路进行了初步的实验测试，讨论了相关参数的设定及其对于谐振的影响，为进一步开发高性能三相软开关双PWM变频器打下了基础。
关键字：变频器；并联谐振直流环节；PWM技术；DSP；软开关技术

Abstract：In the 21st century，the power electronic products ought be“green”，whose pollution to environment is none or very low. So, it is very important significance about how to achieve this target in inverter application field. The aim of this research is to use DC link parallel resonance three---phase soft---switching technique to realize in inverter. In addition, with selecting TI Company’s DSP TMS320LF2407 as controller, the new strategy toward induction motor is studied.
In this thesis SAPWM theory and the soft---switching technology in DC---AC inverter are first described. As the key of this thesis, the soft---switching topology proposed by this project is discussed in detail, including the mathematics analysis on its working principles which can be divided into 9 modes. Two part of the hardware used in the experiment are main circuit and the control circuit. IPM is the kernel of the main circuit. The control circuit is composed of the PCB grounded on TMS320LF2407 DSP and its evaluation module.
The ZVS circuit in the inverter is preliminarily tested in experiment and the influence of the relevant parameters on the this dissertation in order to further develop the high per for three---phase soft---switching double PWM inverter.
Keywords: Inverter； Parallel Resonance DC link；PWM(Pulse-width Modulation) technology；DSP（Digital Signal Processing）；Soft---Switching

目 录

摘要..................................................................Ⅰ abstract.............................................................Ⅱ
第1章  绪论..........................................................1    

1.1 课题研究背景与研究目的..............................................1    

1.2 变频器的原理与发展....................................................2
        1.2.1 变频器的构成.................................................2
        1.2.2 变频器的发展历程.............................................3
1.3 现代逆变技术的发展......................................................3

1.3.1 现代逆变系统的基本组成................................................4
1.3.2 电力电子开关器件的发展................................................4
1.3.3 逆变中PWM技术.......................................................5

1.4 传统PWM硬开关逆变器存在的问题...........................................6
1.5 软开关变换电路的提出与发展..............................................6
1.6 dsp 控制的简介........................................................7
1.7 主要任务与内容........................................................7
第2章  软开关谐振变换技术的基本原理及其发展...................................9
2.1 软开关的基本描述.......................................................9

2.1.1软开关的种类.........................................................9

2.1.2软开关的基本原理及优点................................................10
2.2 软开关谐振变换技术....................................................11

2.2.1谐振的基本原理.......................................................11

2.2.2准谐振与多谐振变换器..................................................13
2.2.3零电流开关(ZCS)与零电压开关(ZVS)变换器................................14

2.3 直流环节谐振型逆变器..................................................15
2.3.1谐振直流环节型逆变器(RDCLI)及其控制策略...............................15

2.3.2并联谐振直流环节逆变器的改进拓扑.......................................17
2.4 本章小结............................................................17

第3章  DSP的结构与功能...................................................18
3.1 引言...............................................................18
3.2 TMS320LF2407芯片概述................................................18
3.3 DSP数字控制器的硬件平台...............................................20
3.4 DSP实现A/D转换的原理.................................................22
3.5 本章小结............................................................22
第4章  三相软开关PWM变频器逆变原理与实现....................................23
4.1 三相PWM逆变器主电路原理...............................................23
4.2 工作模式及其数学分析..................................................23
4.3 系统总体结构.........................................................29

4.4 变频器PWM调制原理....................................................30   

4.4.1 PWM变频技术.......................................................30   

4.4.2 正弦波脉宽调制原理................................................30
   4.4.3 SPWM规则采样法................................................30
4.5 PWM变频器的控制方法.................................................31

4.5.1 选用三角波调制方式的局限性..........................................31

4.5.2 SAPWM基本原理....................................................32

4.5.3 PWM变频器的控制方式................................................33
4.6 ZVS的控制及参数分析..................................................35
4.6.1 电流极性判别.......................................................35
4.6.2 谐振环节vc1、vc2、vs时序设计........................................36
4.6.3谐振电感和缓冲电容的作用..............................................37
    4.7  电机正反转控制分析...............................................37
4.8 本章小结.............................................................38
第5章  软开关变频器的软件设计..............................................39
5.1引言.................................................................39

5.2系统软件流程图........................................................39

5.3各功能模块流程图及简要介绍.............................................40
5.3.1 SPWM模块.........................................................40

5.3.2数据采集A/D模块.....................................................42

5.3.3数制转换模块........................................................42

5.3.4数字PID模块........................................................44

5.3.5 RSC模块...........................................................45
5.4 电机正反转控制算法流程图..............................................47
5.5本章小结.............................................................47
第6章  仿真与实验分析 ...................................................48
6.1 引言...............................................................48
6.2 各模块仿真图........................................................48
6.2.1 谐振部分仿真......................................................48
6.2.2 整流输出波形......................................................50
6.2.3 PWM逆变波形.......................................................51
6.3 仿真结果与分析.......................................................52
6.3.1硬开关变频器的仿真..................................................52
6.3.2软开关变频器的仿真..................................................53
6.4本章小结.............................................................54
结束语..................................................................55
参考文献................................................................56
致谢....................................................................58

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