-
摘 要随着电力电子技术的迅速发展，各种有电力电子装置参与的电路和系统在电力、工业、交通及家庭中的应用逐渐普遍，例如常见的PWM 电压型逆变技术也广泛应用于航空、航海、电力、铁路交通等诸多领域。我们知道，当PWM 电压型逆变器接入电网时将会引起谐波，从而影响电能质量，因此谐波以及由谐波所造成的危害也日益引起人们的关注和重视，通过对逆变电路的谐波进行分析，更详细地了解和掌握谐波的成分和特点，对减少和抑制谐波的研究具有非常重要的意义。本文针对单相 SPWM 电压型逆变电路，选择 PWM 控制技术中一种最具有代表性的 SPWM 控制方式，以正弦波为调制信号波，等腰三角波为载波，根据SPWM 的基本原理和傅里叶级数理论，首先对单相 SPWM 单极性和双极性两种逆变电路的输出电压所含有的谐波进行理论计算分析，找到其谐波的大致分布规律。然后综合运用计算机技术，利用 MATLAB/Simulink 中的基础模块，对这两种逆变电路建立仿真模型，得到对应电路输出电压的时域图形。在此基础上，再利用 FFT Analysis 得到对应的频域图形并进行相应分析，验证上述理论分析的正确性。同时改变参数调制度、载波比，再观察分析变化后的输出电压频谱，研究这些参数变化对于谐波的影响，并得出结论，从而完成对整个电路的谐波分析。58605
- 上一篇：PLC船舶损管系统设计+梯形图
- 下一篇：神经网络分类器的设计与实现
毕业论文关键词：SPWM；单相逆变；谐波分析；MATLAB
Abstract With the rapid development of power electronic technology, the application of all kindsof circuits and systems with power electronic devices in power system, industry, transportati-on and family is gradually universal,for example, the PWM voltage type inverter technologyis also widely used in aviation, navigation, power, railway transportation and many otherfields. We all know,when a PWM voltage type inverter connected to the grid ,it will causeharmonics, which can affect the power quality, so harmonics and the hazards caused by themincreasingly draw more and more people's attention, according to the analysis of its harmonicsof the inverter circuit, there will be a more detailed understanding and a grasp of the characte-ristics and components of the harmonics, which has a very important significance to decreaseand suppress the harmonics.Based on the single-phase SPWM voltage type inverter circuit,this airticle has chosen theSPWM control method,which is the most representative in PWM control technology,and sinewave as the modulation wave, isosceles triangle wave as the carrier wave. According to thebasic theory of PWM control technology and Fourier series,firstly making theoretical analysisfor the harmonics contained of the output voltage of single-phase SPWM unipolar and bipolarinverter circuits,and getting the general regularities of the distribution of the harmonics. Thenusing the computer technology and the basic modules of MATLAB/Simulink comprehensiv-ely, we can establish the simulation models of the two kinds of inverter circuits, as well asgetting the time-domain graphs of the output voltage of its corresponding circuit. On thisbasis, then using the FFT Analysis to obtain the corresponding frequency-domain graphs andmake analysis to verify the correctness of the above theoretical analysis. At the same time,wecan change some parameters,such as the modulation and carrier to noise ratio, then observeand analyse the corresponding frequency content to study the influence of these parameters toharmonics,then draw a conclusion. finally,completing the harmonic analysis of the circuits.
Keywords:SPWM; Single-phase inverter;Harmonic analysis;MATLAB
目 录
第一章 绪论-1
1.1 选题的背景与意义1
1.2 逆变技术的发展与应用2
1.2.1 逆变技术的发展史与不足2
1.2.2 逆变技术的利用3
1.3 谐波分析的相关说明3