發(fā)布時間：2018-01-28 19:48

  本文關鍵詞： PV-AF系統(tǒng) CPT MPPT 光伏發(fā)電系統(tǒng) 有源電力濾波器 重復H_∞控制 阻抗　出處：《中國礦業(yè)大學》2014年博士論文　論文類型：學位論文

【摘要】：近年來，在人類社會科技與經濟高速發(fā)展的過程中，不可再生能源的大量使用帶來了嚴重的環(huán)境污染和生態(tài)惡化的問題，嚴重地影響了社會的發(fā)展和人類的健康，太陽能、潮汐能和風能等可再生能源的利用引起了廣泛的重視。光伏發(fā)電系統(tǒng)是太陽能利用的重要形式，而且具有有源濾波功能的光伏發(fā)電（PhotovoltaicPower Generation and Active Filter，PV-AF）系統(tǒng)拓寬了光伏發(fā)電系統(tǒng)的功能，在實現(xiàn)向電網(wǎng)注入有功電能的同時，還能有效地抑制電網(wǎng)中的諧波等問題，具有廣闊的發(fā)展及應用前景。本文針對接入三相四線制低壓電網(wǎng)的四橋臂PV-AF系統(tǒng)關鍵技術進行了研究。 在分析基于保守功率理論（Conservative Power Theory，，CPT）的諧波電流檢測方法的基礎上，針對電網(wǎng)電壓畸變的情況，提出了一種基于電網(wǎng)電壓消諧的改進型CPT諧波電流檢測方法，通過提取公共連接點電壓中的基波成分，抑制電壓中諧波成分對補償電流計算的影響。仿真和實驗驗證了所提方法的合理性及可行性。 最大功率點跟蹤（Maximum Power Point Tracking，MPPT）技術是提高能量轉換的關鍵環(huán)節(jié)，決定了四橋臂PV-AF系統(tǒng)的工作效率，本文對各種MPPT方法進行了比較，對擾動觀察法在最大功率點（Maximum Power Point，MPP）附近的振蕩進行了分析，研究了系統(tǒng)工作點處于MPP附近的判斷方法，提出了一種擾動觀察法與恒定電壓法相結合的改進型MPPT新方法。實驗和仿真表明該方法能夠準確快速地跟蹤最大功率點。 四橋臂PV-AF系統(tǒng)的控制策略中，電壓外環(huán)用于直流側電壓的控制和最大功率點的跟蹤，電流內環(huán)用于跟蹤基波并網(wǎng)電流和電網(wǎng)中諧波電流指令，電流環(huán)控制性能至關重要，本文提出了一種基于PI和重復H_∞控制的復合控制器的電流環(huán)控制策略，PI控制環(huán)節(jié)保證系統(tǒng)的動態(tài)性能，內模環(huán)節(jié)使得穩(wěn)態(tài)誤差更小，魯棒控制環(huán)節(jié)有效增強了系統(tǒng)的抗干擾性能，在連續(xù)域對復合控制器參數(shù)進行設計，通過離散化完成控制器的數(shù)字實現(xiàn)，并且在離散域中研究了離散化對系統(tǒng)性能的影響。在不同情況下對提出的復合控制器進行了實驗和仿真驗證，結果表明系統(tǒng)具有良好的動態(tài)性能、更小的穩(wěn)態(tài)誤差和優(yōu)良的魯棒性，具有穿越低電壓區(qū)域的能力。 針對系統(tǒng)中存在的負阻抗將會影響系統(tǒng)穩(wěn)定性的問題，本文研究了基于小信號模型的四橋臂PV-AF系統(tǒng)阻抗建模，對不同控制策略下參數(shù)變化對系統(tǒng)阻抗特性的影響進行了比較研究。驗證了優(yōu)化后的復合控制器參數(shù)，在保證系統(tǒng)性能的前提下，能夠有效地減小負阻抗對系統(tǒng)穩(wěn)定性的影響。 主電路參數(shù)是影響四橋臂PV-AF系統(tǒng)性能的關鍵因素之一，本文對四橋臂PV-AF系統(tǒng)主電路參數(shù)進行了設計，對器件進行了選型，搭建了5kVA三相四橋臂PV-AF系統(tǒng)實驗平臺。
[Abstract]:In recent years, in the process of rapid development of science, technology and economy of human society, the massive use of non-renewable energy has brought serious environmental pollution and ecological deterioration problems. Has seriously affected the development of society and human health, solar energy, tidal energy and wind energy and other renewable energy utilization has attracted widespread attention. Photovoltaic power generation system is an important form of solar energy utilization. And the photovoltaic power Generation and Active Filter with active filter function. PV-AFS system broadens the function of photovoltaic power generation system and can effectively suppress the harmonics while injecting active power into the power grid. In this paper, the key technologies of four-arm PV-AF system connected to three-phase four-wire low-voltage power network are studied. Based on the analysis of harmonic current detection method based on conservative power theory, Conservative Power Theoryne (CPT), this paper aims at the situation of voltage distortion in power grid. An improved CPT harmonic current detection method based on grid voltage harmonic elimination is proposed. The fundamental component of common connection voltage is extracted. The influence of harmonic components in the suppression voltage on the calculation of the compensation current is verified by simulation and experiments, and the rationality and feasibility of the proposed method are verified. Maximum Power Point tracking (MPPT) is a key step to improve energy conversion. The efficiency of the four-arm PV-AF system is determined. In this paper, various MPPT methods are compared, and the perturbation observation method is compared at maximum Power Point. The oscillation near MPP) is analyzed, and the judgment method of system working point near MPP is studied. An improved MPPT method combining perturbation observation method with constant voltage method is proposed. Experiments and simulations show that the proposed method can track the maximum power points accurately and quickly. In the control strategy of four-arm PV-AF system, the voltage outer loop is used to control the DC side voltage and track the maximum power point, and the current inner loop is used to track the fundamental grid-connected current and the harmonic current instructions in the power network. The performance of current loop control is very important. In this paper, a current loop control strategy based on Pi and repetitive H _ 鈭

本文編號：1471395