本文選題：級聯(lián)H橋　切入點：光伏系統(tǒng)　出處：《合肥工業(yè)大學》2017年碩士論文

【摘要】：由于傳統(tǒng)發(fā)電造成的環(huán)境污染問題和光伏電池板價格持續(xù)創(chuàng)新低,太陽能從眾多種類的可再生能源中拔地而起,因而光伏逆變器成為國內外學者和公司研究的重點。級聯(lián)H橋多電平逆變器具有模塊化易拓展、效率高、可以產生高質量的并網電流等優(yōu)勢,并且光伏電池板正好解決了該拓撲結構需要大量直流源的缺點,因此級聯(lián)H橋多電平逆變器被應用于光伏并網逆變器最合適不過了。盡管級聯(lián)H橋逆變器已成功運用于有源濾波器等等電力變換場合,但是在光伏產品中的應用仍剛起步,也必然會面對很多問題。本文重點針對單相和三相級聯(lián)H橋光伏并網逆變器中存在的相內和相間功率不平衡問題,做了以下幾點研究:(1).對單相級聯(lián)H橋光伏并網逆變器進行數(shù)學建模,分析不平衡產生的原因和導致的后果,并引出一塊或多塊PV板被完全遮蔽而成為虛設單元的特殊工況。要實現(xiàn)不同不平衡條件下的功率平衡控制以及維持虛設單元電容電壓的穩(wěn)定,本文提出一種改進的混合調制策略(H-PWM)。基于上述對單相級聯(lián)H橋光伏并網逆變器相內功率不平衡控制的研究,提出一套級聯(lián)H橋光伏并網系統(tǒng)控制流程和狀態(tài)切換方案,保證了系統(tǒng)在不同工況下的穩(wěn)定運行。(2).對三相級聯(lián)H橋光伏并網逆變器進行數(shù)學建模,詳細分析了零序分量對三相功率分配產生的影響,接下來本文提出一種基于實際功率誤差的相間功率平衡算法,因此該方法具有控制結構簡單,通訊數(shù)據(jù)較少,良好的動態(tài)性能和明確的物理意義等優(yōu)點,且能夠簡單準確地抑制兩種功率不平衡。最后通過仿真結果驗證多提出的控制算法的正確性和有效性。(3).為滿足級聯(lián)系統(tǒng)達到并網要求,對級聯(lián)H橋光伏并網系統(tǒng)進行理論計算與設計;按照理論計算要求設計H橋功率單元模塊,主控制器板以及并網接口板硬件電路,最終搭建單相10KW級聯(lián)H橋光伏并網樣機,對比驗證所提控制策略的正確性和可靠性。
[Abstract]:Because of the environmental pollution caused by traditional power generation and the low price of photovoltaic panels, solar energy has emerged from many kinds of renewable energy, so photovoltaic inverter has become the research focus of scholars and companies at home and abroad.Cascaded H-bridge multilevel inverter has the advantages of easy modularization, high efficiency, high quality grid-connected current and so on, and the photovoltaic panel solves the problem that the topology requires a large number of DC sources.Therefore, cascaded H-bridge multilevel inverter is most suitable for photovoltaic grid-connected inverter.Although cascaded H-bridge inverter has been successfully applied to active power filter and other power conversion applications, its application in photovoltaic products is still in its infancy, and it is bound to face a lot of problems.This paper focuses on the power imbalance between phase and phase in single-phase and three-phase cascaded H-bridge photovoltaic grid-connected inverters.The mathematical modeling of single-phase cascaded H-bridge photovoltaic grid-connected inverter is carried out, and the causes and consequences of the imbalance are analyzed, and one or more PV plates are completely shielded and become the special condition of the virtual unit.In order to realize power balance control under different unbalanced conditions and to maintain the stability of capacitive voltage of virtual unit, an improved hybrid modulation strategy is proposed in this paper.Based on the above research on the in-phase power imbalance control of single-phase cascaded H-bridge photovoltaic grid-connected inverter, a set of control flow and state switching scheme of cascaded H-bridge photovoltaic grid-connected system are proposed to ensure the stable operation of the system under different operating conditions.Mathematical modeling of three-phase cascaded H-bridge photovoltaic grid-connected inverter is carried out, and the influence of zero-sequence component on three-phase power distribution is analyzed in detail. Then, a phase-to-phase power balance algorithm based on actual power error is proposed.Therefore, this method has the advantages of simple control structure, less communication data, good dynamic performance and clear physical meaning, and can easily and accurately suppress the two kinds of power imbalance.Finally, the simulation results verify the correctness and effectiveness of the proposed control algorithm.In order to meet the grid connection requirement of cascade system, the theoretical calculation and design of cascaded H-bridge photovoltaic grid-connected system are carried out, and the hardware circuits of H-bridge power unit module, main controller board and grid-connected interface board are designed according to the theoretical calculation requirements.Finally, a single-phase 10KW cascaded H bridge photovoltaic grid-connected prototype is built to verify the correctness and reliability of the proposed control strategy.
【學位授予單位】：合肥工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TM464;TM615

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本文編號：1725990