【摘要】：PWM整流器具有可在單位功率因數下運行、網側電流高度正弦化、能量可雙向傳輸等優(yōu)勢,被普遍應用在有源電力濾波、高壓直流輸電、可再生能源并網發(fā)電等諸多方向。而應用無差拍控制技術可以完成在單個開關周期內被控信號對參考信號的準確跟蹤,并能提供快速的動態(tài)響應,減小網側電流的波形畸變程度。但是為了防止上下功率橋臂同時導通損壞整流橋,必須加入死區(qū)時間進行保護,而死區(qū)時間的加入會造成低次諧波增加、電流發(fā)生畸變等不良影響,不利于無差拍技術對三相PWM整流器的電流精準跟蹤。所以對死區(qū)時間補償十分有必要。本篇在編寫過程中,首先以PWM整流器發(fā)展為背景,簡單對其分種類介紹,并著重對電壓型PWM整流器的控制方法進行論述。通過數學建模的方式展示整流器在靜止坐標系中由三相到兩相變換,以及兩相靜止到同步旋轉坐的標系變換過程。并將空間矢量PWM技術應用到整流橋驅動控制。系統(tǒng)的控制方法為經典的外環(huán)電壓、內環(huán)電流控制。并且在內環(huán)應用無差拍技術,并說明其快速性在電流環(huán)控制中應用的優(yōu)勢。其次,本文著重論述了死區(qū)時間對PWM整流器的不良影響的原因以及造成后果:為了避免整流橋上下橋臂發(fā)生直通人為添加的保護時間,導致較低次諧波增加,網側電流波形發(fā)生畸變。同時對現行的幾種死區(qū)時間補償方法進行原理分析和仿真實驗對比,得出死區(qū)時間補償的關鍵在于對網側電流極性的精準判斷,由于電流存在過零箝位現象干擾極性判斷,于是引入根據網側電流紋波估計值進行電流極性的準確判斷。通過MATLAB/Simulink搭建系統(tǒng)的仿真模型,并證明補償方法的可行性。最后,本文參照三相電壓型PWM整流器的運行相關參數和實驗室已有器件,綜合考慮后對軟件程序和硬件設備進行設計。軟件方面,是以STM32F407ZG為控制核心設計軟件程序;硬件方面,主要對控制電路和主電路進行設計,包括采樣電路、外部基準電源電路、保護電路等電路計算和設計。并通過實驗平臺的實驗調試最終驗證了三相PWM整流器無差拍控制的優(yōu)越性和基于紋波電流判斷電流極性的死區(qū)時間補償的可行性和有效性。
[Abstract]:PWM rectifier is widely used in many fields, such as active power filter, HVDC transmission, renewable energy grid-connected generation and so on, because of its advantages such as unit power factor, high sinusoidal current, two-way energy transmission and so on. The deadbeat control technique can accurately track the reference signal in a single switching cycle and provide a fast dynamic response to reduce the waveform distortion degree of the network side current. However, in order to prevent the upper and lower power arms from simultaneously conducting and damaging the rectifier bridge, the dead-time must be added to protect the rectifier bridge, and the addition of the dead-time will result in the increase of low order harmonics, the distortion of current and other adverse effects. It is unfavorable to accurate current tracking of three-phase PWM rectifier by non-beat technique. So it is necessary to compensate for dead time. In the process of compiling this paper, the development of PWM rectifier is taken as the background, and the control method of voltage source PWM rectifier is discussed in detail. The mathematical modeling is used to show the transformation process of rectifier from three-phase to two-phase in stationary coordinate system and from two-phase static to synchronous rotation. And the space vector PWM technology is applied to the rectifier bridge drive control. The control methods of the system are classical outer loop voltage and inner loop current control. The beat-free technique is applied in the inner loop, and the advantages of its rapidity in current loop control are explained. Secondly, this paper focuses on the causes and consequences of the bad effect of dead-time on PWM rectifier: in order to avoid the artificially added protection time of the upper and lower leg of the rectifier bridge, the lower harmonics are increased. The current waveform of the network side is distorted. At the same time, the principle of several dead-time compensation methods are analyzed and compared with simulation experiments. The key to dead-time compensation lies in the accurate judgment of the current polarity on the network side, and the interference polarity judgment due to the zero-crossing clamping phenomenon of the current exists. Therefore, the current polarity can be accurately judged according to the current ripple estimation of the network side. The simulation model of the system is built by MATLAB/Simulink, and the feasibility of the compensation method is proved. Finally, according to the operating parameters of three-phase voltage-source PWM rectifier and the existing devices in the laboratory, the software program and hardware equipment are designed. In the software aspect, the software program is designed with STM32F407ZG as the control core, and the control circuit and the main circuit are mainly designed in the hardware aspect, including sampling circuit, external reference power circuit, protection circuit and so on circuit calculation and design. The advantages of non-beat control of three-phase PWM rectifier and the feasibility and effectiveness of dead-time compensation based on ripple current to judge the polarity of current are finally verified by the experimental debugging of the experimental platform.
【學位授予單位】：北方工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TM461

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