【正文】
10 有源電力濾波技術(shù)在日本、美國、德國等工業(yè)發(fā)達(dá)國家的發(fā)展和應(yīng)用較為成 熟。現(xiàn)在三相四線系統(tǒng)中的諧波和三相不平衡所產(chǎn)生的問題日趨嚴(yán)重,引起了人們的極大重視。 80年代后期,許多有源電力濾波器的商業(yè)發(fā)展計劃完成并投入了實(shí)踐。此文討論了有源電力濾波器的實(shí)現(xiàn)方法和控 制原理,并建立了有源電力濾波器的基本拓?fù)浣Y(jié)構(gòu)。 根據(jù) APF與被補(bǔ)償系統(tǒng)的連接方式不同, APF可分為:串聯(lián)型有源電力濾波 器 (Series APF如圖 12 a),并聯(lián)型有源電力濾波器 (Shunt APF如圖 12 b)和串并聯(lián)型 (又稱為統(tǒng)一電能質(zhì)量調(diào)節(jié)器 UPQC如圖 12 c)。 (3)補(bǔ)償無功功率時不需要儲能元件,補(bǔ)償諧波時所需儲能元件的容量也 不大。特別是在一個復(fù)雜的電力系統(tǒng)中,這兩個參數(shù)的變化規(guī)律很難精確預(yù)知,因此一個實(shí)際的濾波器要滿足要求的諧波衰減是很困難的。 無源電力濾波器 無源電力濾波器 (原理如圖 11)是傳統(tǒng)的諧波補(bǔ)償方法,目前大量應(yīng)用的 是由交流電抗器和電容器組成的“ LC無源濾波器 (LC Passire Power Filter)”。如:有源功率因數(shù)校正技術(shù) (SPFC),各種 PWM整流技術(shù)等。 諧波抑制強(qiáng) 解決非線性負(fù)載產(chǎn)生的諧波問題思路有二。 (2)在信號干擾方面: 1)諧波通過電磁感應(yīng)和傳導(dǎo)耦合等方式對鄰近的電力電子設(shè)備和通訊系統(tǒng) 本科生畢業(yè)論文 6 產(chǎn)生干擾.嚴(yán)重時還會導(dǎo)致設(shè)備無法正常運(yùn)行。使諧波 電流放大,造成過電流,導(dǎo)致電容器、與之相連的電抗器和電阻器的損壞。 (5)各種民用電力電子設(shè)備。 (2)工業(yè)用電弧爐、逆變焊機(jī)等。其產(chǎn)生的諧波日益嚴(yán)重,引起了世界各國對諧波及其抑制的重視。如電網(wǎng)的諧波、三相不平衡、閃變與頻率變化等。對 SAPF 和所要補(bǔ)償?shù)南到y(tǒng)進(jìn)行了整體仿真,結(jié)果證明在所選參數(shù)下,能夠?qū)ζ胶夂筒黄胶夥蔷€性負(fù)載所帶來的諧波有很好的動態(tài)補(bǔ)償效果,對不平衡負(fù)載有很好的平衡 作用;進(jìn)而也說明檢測方法正確,控制策略得當(dāng)。目前,并聯(lián)有源電力濾波器 (shunt active power filter, SAPF)已成為無功和諧波動態(tài)補(bǔ)償?shù)挠行侄沃?。在三相四線制電力系統(tǒng)中除了無功和諧波需要治理,負(fù)載不平衡問題也變得日益突出,因此,本文研究與設(shè)計適用于三相四線制下的 SAPF來解決這些問題。 關(guān)鍵詞 諧波動態(tài)補(bǔ)償;并聯(lián)有源電力濾波器;三相四線制; qp ii ? 算法 MATLAB/Simulink 本科生畢業(yè)論文 2 Abstract With extensive application of power electronic devices in production and life,they make power energy conversion and application easily, but also lead to the serious harmonic pollution in the power system. At present, the shunt active power filter (SAPF) has been an effective way to dynamically pensate reactive power and harmonic. In addition to these problems, the load unbalance is more and more serious in threephase fourwire system, therefore, SAPF applied to threephase fourwire system is researched and designed to solve these problems in this paper. For the harmonic current detection of SAPF in threephase fourwire system, the qp ii ? algorithm based on the instantaneous reactive theory is detailedly derived, and this algorithm is demonstrated it could be directly applied to threephase and fourwire system without being improved. Hysteresisband parison method is chosen as pensation current control strategy. The threeleg converter which has clear division is adopted as the main circuit. At the end of the paper, the simulation platform is built by use of MATLAB/Simulink software. The output inductance parameter and softstart scheme are simulated respectively. The results prove that output inductance parameter is reasonable and the softstart scheme is feasible. Then, the integrated simulation for SAPF and pensation system is carried out. Finally, simulation results show that SAPF has a good pensation characteristic for the harmonic produced by the balance and unbalance nonlinear loads, and balances threephase loads in threephase and fourwire system. At the same time, simulation results show that harmonic detection method is correct and the control strategy is proper. Keywords : harmonic dynamic pension; shunt active power filter; threephase fourwire system; qp ii ? algorithm; MATLAB/Simulink 本科生畢業(yè)論文 3 第一章 緒論 ................................................................................................................... 5 諧波概述及其危害 .............................................................................................. 5 諧波抑制強(qiáng) ................................................................................................. 6 無源電力濾波器 ....................................................................................... 6 有源電力濾波器 ....................................................................................... 6 混合型有源電力濾波器 ............................................................................ 8 有源電力濾波器的發(fā)展和應(yīng)用 ............................................................................ 9 有源電力濾波器的發(fā)展 ............................................................................ 9 有源電力濾波器的應(yīng)用 ............................................................................ 9 本文的研究的意義和內(nèi)容設(shè)置及主要任務(wù) ..........................................................10 第二章 三相電路諧波及無功電流的檢測 ........................................................................ 11 基于瞬時無功功率理論的電流檢測方法 ............................................................. 11 瞬時無功理論原始定義及發(fā)展 ................................................................. 11 2. 1. 2 瞬時無功功率理論 .................................................................................. 11 2. 1. 3 坐標(biāo)變換 ................................................................................................16 三相四線制系統(tǒng)中基于瞬時無功功率理論的檢測方法 ......................................17 qp? 法檢測電流 ..................................................................................17 2. 2. 2 qd ii? 指令運(yùn)算方法 ............................................................................17 諧波分量的處理 ................................................................................................18 對基波零序分量的處理 ...........................................................................18 對基波負(fù)序分量和高次諧波分量的處理 ...................................................19 qp? 運(yùn)算方式和 qp ii ? 運(yùn)算方式的優(yōu)缺點(diǎn) ........................................................19 第三章 并聯(lián)型三相四線制補(bǔ)償電流發(fā)生電路方案選擇 ...................................................20 三相四線制系統(tǒng) APF 主電路形式和結(jié)構(gòu)選擇設(shè)計 ...............................................20 本科生畢業(yè)論文 4 四相變流器結(jié)構(gòu)形式 ...............................................................................21 三相變流器結(jié)構(gòu) ......................................................................................21 3. 2 三相四線并聯(lián)型有源電力濾波器主電路的參數(shù)選擇 ............................................22 3. 2. 1 主電路容量的確定 ...................................................................................22 3. 2. 2 系統(tǒng)開關(guān)頻率 ..................................