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  本文關(guān)鍵詞： 并網(wǎng)逆變器 最大功率點(diǎn)跟蹤 雙閉環(huán) 電流前饋 PI控制　出處：《遼寧工業(yè)大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：光伏并網(wǎng)逆變器是光伏并網(wǎng)發(fā)電系統(tǒng)的核心組成部分。本文以三相雙級式并網(wǎng)逆變器為研究對象，對光伏并網(wǎng)逆變器的兩大核心問題——最大功率點(diǎn)跟蹤（MPPT）和逆變器并網(wǎng)雙閉環(huán)PI控制問題進(jìn)行深入研究，解決最大功率點(diǎn)跟蹤速度與穩(wěn)態(tài)振蕩的矛盾，實現(xiàn)逆變器并網(wǎng)電流無誤差地跟蹤網(wǎng)側(cè)電壓。 針對最大功率點(diǎn)跟蹤速度慢與穩(wěn)態(tài)振蕩等問題，本文深入比較分析了電導(dǎo)增量法等典型MPPT算法，，提出一種改進(jìn)的變步長電導(dǎo)增量最大功率點(diǎn)跟蹤速算法。該算法結(jié)合了定電壓法與變步長電導(dǎo)增量法的優(yōu)點(diǎn)，仿真結(jié)果表明改進(jìn)的變步長電導(dǎo)增量法能夠快速地跟蹤到當(dāng)前最大功率點(diǎn)處，且進(jìn)入穩(wěn)態(tài)后無振蕩現(xiàn)象。 為實現(xiàn)逆變器并網(wǎng)電流無誤差地跟蹤網(wǎng)側(cè)電壓問題，本文以三相雙級式并網(wǎng)逆變器為研究對象，并確定并網(wǎng)逆變器主電路拓?fù)浣Y(jié)構(gòu)。分析了三相SPWM與SVPWM技術(shù)應(yīng)用于逆變器調(diào)制的優(yōu)缺點(diǎn)，建立三相逆變器模型，仿真結(jié)果表明采用SVPWM調(diào)制的逆變器輸出電壓及電流的諧波性能好，直流電壓利用率最高。同時仿真分析了死區(qū)時間對逆變器輸出的影響以及L與LCL濾波器的設(shè)計方法與性能。 光伏并網(wǎng)逆變器系統(tǒng)的仿真研究。搭建具有電流前饋功能的電流內(nèi)環(huán)、電壓外環(huán)的雙閉環(huán)PI并網(wǎng)控制策略的系統(tǒng)仿真模型。仿真結(jié)果表明相對于一般的雙閉環(huán)并網(wǎng)控制策略，帶電流前饋功能的雙閉環(huán)控制策略可以更好的實現(xiàn)逆變器的并網(wǎng)控制。逆變器電流能夠無差地跟蹤網(wǎng)側(cè)電壓頻率，正弦度好，諧波��；在光照強(qiáng)度發(fā)生變化時，逆變器可快速調(diào)整功率輸出，在過渡過程中無振蕩。
[Abstract]:Photovoltaic grid-connected inverter is the core part of photovoltaic grid-connected power generation system. In this paper, two core problems of photovoltaic grid-connected inverter, maximum power point tracking (MPPTT) and grid-connected double closed loop Pi control, are studied in order to solve the contradiction between maximum power point tracking speed and steady state oscillation. The inverter grid-connected current can track the voltage of grid-side without error. Aiming at the problems of slow tracking speed and steady state oscillation of the maximum power point, the typical MPPT algorithms such as conductance increment method are compared and analyzed in this paper. An improved variable step length maximum power point tracking algorithm is proposed, which combines the advantages of the constant voltage method and the variable step length conductance increment method. The simulation results show that the improved variable step length conductance increment method can quickly track the current maximum power point, and there is no oscillation after entering the steady state. In order to track the voltage of grid-connected inverter without error, this paper takes the three-phase double-stage grid-connected inverter as the research object. The topology of the main circuit of grid-connected inverter is determined. The advantages and disadvantages of three-phase SPWM and SVPWM in inverter modulation are analyzed, and the model of three-phase inverter is established. The simulation results show that the inverter with SVPWM modulation has good harmonic performance of output voltage and current, and the highest utilization rate of DC voltage. At the same time, the effect of dead-time on the output of inverter and the design method and performance of L and LCL filter are simulated and analyzed. Simulation study of photovoltaic grid-connected inverter system. The system simulation model of double-closed-loop Pi grid-connected control strategy with current feedforward function and voltage outer loop is built. The simulation results show that compared with the conventional double-closed-loop grid-connected control strategy, the simulation results show that, Double closed loop control strategy with current feedforward function can better realize grid-connected control of inverter. Inverter current can track voltage frequency of grid-side without difference, sinusoidal degree is good, harmonic is small, and when illumination intensity changes, The inverter can adjust the power output quickly and has no oscillation during the transition.
【學(xué)位授予單位】：遼寧工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TM464

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