無變壓器光伏并網(wǎng)逆變器的漏電流抑制研究
發(fā)布時(shí)間：2018-07-21 14:40
【摘要】：在能源危機(jī)和環(huán)境污染的雙重壓力下,以光伏發(fā)電產(chǎn)業(yè)為代表的新能源產(chǎn)業(yè)成為人類當(dāng)下關(guān)注和研究的焦點(diǎn)問題之一。作為光伏發(fā)電系統(tǒng)核心設(shè)備之一的光伏并網(wǎng)逆變器,當(dāng)下對其的研究焦點(diǎn)不僅限于對其輸出電能的優(yōu)化,更將效率優(yōu)化作為追求目標(biāo)。無變壓器光伏并網(wǎng)逆變器無需變壓器隔離作用,減小了系統(tǒng)體積、降低了成本、提高了效率,具有很大的研究價(jià)值。由于光伏電池板存在對地寄生電容,在沒有變壓器的情況下,電網(wǎng)與光伏發(fā)電系統(tǒng)之間失去了電氣隔離作用,形成共模電壓回路。共模電壓的高頻振蕩會帶來較大的漏電流,不僅造成入網(wǎng)電流畸變,還有可能帶來設(shè)備損害、人員傷亡,因此必須嚴(yán)格控制漏電流的大小。因此漏電流的抑制成為研究無變壓器光伏并網(wǎng)逆變器的關(guān)鍵問題之一�；谡{(diào)制的漏電流抑制方法無需添加元器件,無需改變電路結(jié)構(gòu)與控制器設(shè)計(jì),受到國內(nèi)外研究人員的廣泛關(guān)注。本文將分別研究兩電平和三電平無變壓器光伏并網(wǎng)逆變器基于調(diào)制的漏電流抑制方法。為了更好的分析抑制漏電流的原理,對三相光伏逆變器的漏電流模型進(jìn)行了小信號建模,從其激勵(lì)源、環(huán)路阻抗和傳統(tǒng)調(diào)制三方面分析了漏電流產(chǎn)生的原理,明確各項(xiàng)電氣參數(shù)與寄生參數(shù)對漏電流的影響。針對兩電平無變壓器光伏并網(wǎng)逆變器的漏電流問題,文本著重分析了兩類典型的調(diào)制算法,AZSPWM和RSPWM抑制漏電流的原理及實(shí)現(xiàn)方法,并提出一種基于RSPWM調(diào)制的死區(qū)共模電壓補(bǔ)償算法,使RSPWM可以應(yīng)用于帶死區(qū)的開關(guān)驅(qū)動(dòng)下。本文對這兩類調(diào)制算法的直流電壓利用率和輸出電壓諧波進(jìn)行了理論分析,并與傳統(tǒng)SVPWM調(diào)制算法進(jìn)行了對比,為AZSPWM與RSPWM的工程應(yīng)用提供了理論參考。針對三電平無變壓器光伏并網(wǎng)逆變器的漏電流問題,本文著重分析了三種典型的中矢量調(diào)制算法,2MV1Z、3MV120和3MV抑制漏電流的原理和實(shí)現(xiàn)方法。中矢量調(diào)制算法不僅可以理論上消除漏電流,且對直流側(cè)電壓利用率較大,具有很大的研究價(jià)值。本文理論分析了三種中矢量調(diào)制算法的調(diào)制比范圍、輸出電壓諧波、輸入電流紋波性能,并對其產(chǎn)生的功率器件損耗進(jìn)行了仿真分析,為三種中矢量調(diào)制算法的工程應(yīng)用提供了理論參考。本文對所有理論分析提供了仿真驗(yàn)證。
[Abstract]:Under the dual pressure of energy crisis and environmental pollution, the new energy industry, represented by photovoltaic power generation industry, has become one of the focuses of human attention and research. As one of the core equipment of photovoltaic power generation system, the research focus of grid-connected photovoltaic inverter is not only the optimization of its output energy, but also the optimization of efficiency as its goal. The photovoltaic grid-connected inverters without transformers do not need transformer isolation, reduce system volume, reduce costs, improve efficiency, and have great research value. Because of the parasitic capacitance of photovoltaic panels, the electrical isolation between the power grid and the photovoltaic system is lost without a transformer, and a common-mode voltage loop is formed. The high frequency oscillation of common-mode voltage will bring large leakage current, which will not only cause distortion of the current into the network, but also may cause damage to the equipment and casualties. Therefore, the leakage current must be strictly controlled. Therefore, the suppression of leakage current becomes one of the key problems in the research of transformerless photovoltaic grid-connected inverter. Modulation-based leakage current suppression method does not need to add components, do not need to change the circuit structure and controller design, so it has been widely concerned by researchers at home and abroad. In this paper, two level and three level transformerless photovoltaic grid-connected inverters are studied respectively. In order to better analyze the principle of restraining leakage current, the leakage current model of three-phase photovoltaic inverter is modeled with small signal, and the principle of leakage current generation is analyzed from three aspects: excitation source, loop impedance and traditional modulation. The influence of electrical parameters and parasitic parameters on leakage current is clarified. Aiming at the leakage current of photovoltaic grid-connected inverter with two-level transformer, the principle and implementation of two typical modulation algorithms, namely AZSPWM and RSPWM, are analyzed in this paper. A dead zone common-mode voltage compensation algorithm based on RSPWM modulation is proposed. In this paper, the DC voltage utilization and output voltage harmonics of these two modulation algorithms are theoretically analyzed, and compared with the traditional SVPWM modulation algorithm, which provides a theoretical reference for the engineering application of AZSPWM and RSPWM. In order to solve the leakage current problem of three-level grid-connected photovoltaic inverter without transformer, the principle and implementation of three typical mid-vector modulation algorithms (2MV1ZN3MV120 and 3MV) are analyzed in this paper. The medium vector modulation algorithm not only can eliminate leakage current theoretically, but also has great research value for DC side voltage utilization ratio. In this paper, the modulation ratio range, output voltage harmonics, input current ripple performance of three vector modulation algorithms are theoretically analyzed, and the power device losses generated by them are simulated and analyzed. It provides a theoretical reference for the engineering application of three kinds of vector modulation algorithms. This paper provides simulation verification for all the theoretical analysis.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TM464;TM615
本文編號：2135850
[Abstract]:Under the dual pressure of energy crisis and environmental pollution, the new energy industry, represented by photovoltaic power generation industry, has become one of the focuses of human attention and research. As one of the core equipment of photovoltaic power generation system, the research focus of grid-connected photovoltaic inverter is not only the optimization of its output energy, but also the optimization of efficiency as its goal. The photovoltaic grid-connected inverters without transformers do not need transformer isolation, reduce system volume, reduce costs, improve efficiency, and have great research value. Because of the parasitic capacitance of photovoltaic panels, the electrical isolation between the power grid and the photovoltaic system is lost without a transformer, and a common-mode voltage loop is formed. The high frequency oscillation of common-mode voltage will bring large leakage current, which will not only cause distortion of the current into the network, but also may cause damage to the equipment and casualties. Therefore, the leakage current must be strictly controlled. Therefore, the suppression of leakage current becomes one of the key problems in the research of transformerless photovoltaic grid-connected inverter. Modulation-based leakage current suppression method does not need to add components, do not need to change the circuit structure and controller design, so it has been widely concerned by researchers at home and abroad. In this paper, two level and three level transformerless photovoltaic grid-connected inverters are studied respectively. In order to better analyze the principle of restraining leakage current, the leakage current model of three-phase photovoltaic inverter is modeled with small signal, and the principle of leakage current generation is analyzed from three aspects: excitation source, loop impedance and traditional modulation. The influence of electrical parameters and parasitic parameters on leakage current is clarified. Aiming at the leakage current of photovoltaic grid-connected inverter with two-level transformer, the principle and implementation of two typical modulation algorithms, namely AZSPWM and RSPWM, are analyzed in this paper. A dead zone common-mode voltage compensation algorithm based on RSPWM modulation is proposed. In this paper, the DC voltage utilization and output voltage harmonics of these two modulation algorithms are theoretically analyzed, and compared with the traditional SVPWM modulation algorithm, which provides a theoretical reference for the engineering application of AZSPWM and RSPWM. In order to solve the leakage current problem of three-level grid-connected photovoltaic inverter without transformer, the principle and implementation of three typical mid-vector modulation algorithms (2MV1ZN3MV120 and 3MV) are analyzed in this paper. The medium vector modulation algorithm not only can eliminate leakage current theoretically, but also has great research value for DC side voltage utilization ratio. In this paper, the modulation ratio range, output voltage harmonics, input current ripple performance of three vector modulation algorithms are theoretically analyzed, and the power device losses generated by them are simulated and analyzed. It provides a theoretical reference for the engineering application of three kinds of vector modulation algorithms. This paper provides simulation verification for all the theoretical analysis.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TM464;TM615
【參考文獻(xiàn)】
相關(guān)碩士學(xué)位論文 前1條
1 文家燕;光伏并網(wǎng)逆變器共模電壓抑制方法和實(shí)驗(yàn)研究[D];合肥工業(yè)大學(xué);2012年
，本文編號：2135850
本文鏈接：http://sikaile.net/kejilunwen/dianlilw/2135850.html
最近更新
教材專著
