变频器输出切换的理论分析与实现方法研究

【实例简介】变频器输出切换的理论分析与实现方法研究

用单台变频器拖动多台电机变频运行，进行恒压供水自动控制，是诸多供水企业所面临的技术难题。变频器的输出切换问题，目前尚未得到足够的重视，若直接采用硬切换方式，不仅达不到变频软起动的目的，而且会产生严重的后果。特别是大功率电机，直接切换会产生极大的危险性，对电机、电控设备和电网都会产生很大的冲击和破坏。本论文针对大功率电机变频转工频存在的问题，对变频器输出切换问题进行理论分析和实现方法研究

【实例截图】

【核心代码】

目 录
摘 要 ······································································································································I
ABSTRACT ····························································································································· II
第一章 绪 论
1.1 课题背景和意义 ······································································································ - 1 -
1.2 三种启动方式简介及比较 ····················································································· - 1 -
1.3 变频器输出切换的国内外研究现状 ··································································· - 4 -
1.4 本论文研究内容 ······································································································ - 5 -
第二章 变频器输出切换的静态分析
2.1 三相感应电机的磁动势和磁场 ············································································· - 7 -
2.2 三相感应电机的电压方程 ····················································································· - 8 -
2.2.1 三相感应电机的定子电压方程 ····································································- 8 -
2.2.2 三相感应电机的转子电压方程 ····································································- 8 -
2.3 感应电动机的功率方程和转矩方程 ···································································· - 9 -
2.3.1 功率方程、电磁功率和转换功率 ································································- 9 -
2.3.2 转矩方程和电磁转矩 ··················································································· - 10 -
2.4 变频器输出切换的静态分析 ············································································- 11 -
2.4.1 变频器输出切换原理 ··················································································· - 11 -
2.4.2 变频器输出切换过程存在的问题 ····························································· - 11 -
2.4.3 变频器输出切换的静态分析 ······································································ - 12 -
2.5 本章小结 ················································································································· - 13 -
第三章 变频器输出切换的动态分析与建模仿真
3.1 交流电机动态分析的特点和步骤 ······································································ - 14 -
3.2 坐标系简介 ············································································································ - 15 -
3.3 坐标变换 ················································································································· - 19 -
3.3.1 从 ABC 坐标系变换到 0 αβ 坐标系 ······························································ - 19 -
3.3.2 从 ABC 坐标系变换 q d、 坐标系 ································································· - 23 -
3.4 动态切换数学模型的建立 ··················································································· - 24 -
3.5 数学模型求解 ········································································································· - 29 -
3.5.1 四阶龙格-库塔方程简介 ············································································ - 29 -
3.5.2 四阶龙格-库塔方程的改进 ········································································ - 29 -
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3.5.3 动态切换过程的仿真分析 ·········································································· - 30 -
3.6 本章小结 ················································································································· - 33 -
第四章 变频器输出切换的实现方法研究
4.1 利用鉴频鉴相器实现变频器输出切换的方法 ················································· - 34 -
4.1.1 鉴频鉴相器的总体方案设计 ······································································· - 34 -
4.1.2 鉴频鉴相器的部分电路设计与分析 ·························································· - 35 -
4.1.3 鉴频鉴相器的电气原理图和 PCB 图 ·························································· - 43 -
4.1.4 利用鉴频鉴相器实现变频器输出切换 ····················································· - 47 -
4.2 锁相环技术在变频器输出切换中的应用 ·························································· - 49 -
4.2.1 锁相环简介及工作原理 ··············································································· - 49 -
4.2.2 锁相环实现大功率电机平稳切换的方法 ················································· - 52 -
4.2.3 锁相环控制电路的仿真分析 ······································································· - 53 -
4.3 本章小结 ················································································································· - 56 -
第五章 变频器输出切换的试验研究
5.1 实验室切换试验 ···································································································· - 57 -
5.1.1 试验的总体方案 ··························································································· - 57 -
5.1.2 试验控制过程的设计 ··················································································· - 58 -
5.1.3 试验的实现 ···································································································· - 61 -
5.1.4 试验结果及分析 ···························································································· - 62 -
5.2 工业现场试验 ········································································································ - 63 -
5.3 本章小结 ················································································································· - 64 -
第六章 总结与展望
6.1 总结 ························································································································· - 65 -
6.2 展望 ························································································································· - 66 -
参 考 文 献 ·······················································································································- 67 -
致 谢 ·······························································································································- 70 -
附录 A：攻读学位期间参研项目和发表论文目录 ········································- 71 -
附录 B：单片机部分程序 ····························································································- 72 -
附录 C：鉴频鉴相器原理图 ·······················································································- 74 -
附录 D：鉴频鉴相器 PCB 板制作图 ······································································- 76 -