发布时间 : 星期六 文章逆变器死区特性的仿真研究更新完毕开始阅读
湖南人文科技学院毕业论文
逆变器死区特性的仿真研究
摘要：随着逆变技术的不断发展，逆变器死区对逆变技术的影响越来越大，尤其是
SPWM电压型逆变器中的死区效应问题仍然很突出，为了防止逆变器同一桥臂上下两个晶闸管同时导通，必须对上下两个晶闸管加入延迟导通时间（死区）。因此死区效应问题引起了广大学者的关注，补偿死区成了改善逆变器输出波形的一个重要课题。
本论文从分析逆变器的死区入手，详细分析了它对逆变器输出电压和整个系统的影响，死区效应使得输出基波电压下降，相位发生变化，低次谐波增加，转矩脉动增大。针对上述影响，本论文采用了电流型反馈补偿方法。通过检测三相电流并转换成电压信号和原来的调制信号电压叠加，产生新的PWM波形对死区进行补偿，从而减小死区对输出电压电流以及异步电动机的转矩脉动的影响。并基于电流反馈补偿方法进行了具体的MATLAB仿真研究，仿真结果表明电流反馈型死区补偿方法的有效性和可行性。本文的研究对于提高和改善变频调速系统的性能以及对死区问题的研究有很好的借鉴意义。
关键字：电压逆变器；脉宽调制(PWM)；死区；电流反馈补偿
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湖南人文科技学院毕业论文
STUDY ON DEAD TIME PROPERTY OF INVERTER Abstract: Inverter technology with the development of modern control theory, dead time
has an serious influence to the PWM Inverter., especially the problem still exsits in the SPWM voltage source inverter. In order to prevent the inverter under the same bridge arm of the two thyristor conduct, the thyristor must be added to the upper and lower thyristor turn-on delay time (dead zone). Dead time effect issues arouse the attention of the masses of scholars. Compensating the influences of dead time becomes a piece of important subject to improve the waveforms of inverter.
This paper studies the dead-time, its effect on the inverter output voltage and the whole system. The effect of dead-time results in reduction of the fundamental component of inverter voltage, phase shifting, addition of unwangted lover order harmonices and increases torque ripples. In order to eliminate the bad effects ,the paper uses current-feedback compensation method. Detecting three phase current and converting into a voltage signal ,which superimposes on the original modulation signal voltage ,the system generates a new PWM waveform to compensate the dead-time. Current-feedback dead-time compensation method studies on the base of matlab and simulation proves the availability and the feasibility of the system. The studies of this paper have the value for improving the performance of the AC machine driver and the further study of the dead-time effect.
Keyword: voltage inverter;Pulse Width Modulation; dead time; current-feedback for
dead-time compensation.
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湖南人文科技学院毕业论文
目 录
第1章 绪论 .............................................................................................................................. 1 1.1 引言 .................................................................................................................................. 1 1.2 逆变技术 .......................................................................................................................... 1 1.2.1 逆变技术的发展过程 ............................................................................................... 1 1.2.2 逆变的目的以及技术优点 ....................................................................................... 3 1.2.3 逆变器主电路的基本形式和分类 ........................................................................... 3 1.3 选题背景及意义 .............................................................................................................. 4 1.4 本文结构和研究内容 ...................................................................................................... 6 第2章 逆变器的非线性特性(死区)分析 ............................................................................... 7 2.1 引言 .................................................................................................................................. 7 2.2 脉宽调制技术(PWM技术)概述 ..................................................................................... 7 2.2.1 PWM简介 .................................................................................................................. 7 2.2.2 SPWM原理分析 ....................................................................................................... 8 2.3 死区的概述 ...................................................................................................................... 9 2.3.1 死区定义 ................................................................................................................... 9 2.3.2 死区产生的原因 ..................................................................................................... 10 2.4 死区对输出电压的影响 ................................................................................................ 11 2.4.1 死区对输出电压的定性分析 ................................................................................. 11 2.4.2 无死区时的输出电压计算 ..................................................................................... 13 2.4.3 有死区时输出电压影响的计算 ............................................................................. 15 2.5 死区对输出电流的影响 ................................................................................................ 17 第3章 死区补偿方法研究 .................................................................................................... 18 3.1 引言 ................................................................................................................................ 18 3.2 死区研究补偿现状 ........................................................................................................ 18 3.3 反馈控制基本理论 ........................................................................................................ 19
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湖南人文科技学院毕业论文
3.4 电流反馈型PWM逆变器死区补偿设计 .................................................................... 20 3.4.1 电压反馈型死区补偿 ............................................................................................. 20 3.4.2 电流反馈型死区补偿 ............................................................................................. 21 第4章 PWM电压型逆变器死区补偿算法仿真 ............................................................... 23 4.1 引言 ................................................................................................................................ 23 4.2 MATLAB仿真以及结果分析 ....................................................................................... 23 4.2.1 MATLAB/SIMULINK简介 .................................................................................... 23 4.2.2 仿真模型 ................................................................................................................. 24 4.3.3 仿真参数设置 ......................................................................................................... 29 4.3.4 仿真结果及其分析 ................................................................................................. 31 第5章 总结及展望 ................................................................................................................ 35 5.1 总结 ................................................................................................................................ 35 5.2展望 ................................................................................................................................ 35 致谢 .......................................................................................................................................... 37 参考文献 .................................................................................................................................. 38
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