无变压器光伏并网逆变器的漏电流抑制研究
发布时间：2018-07-21 14:40
【摘要】：在能源危机和环境污染的双重压力下,以光伏发电产业为代表的新能源产业成为人类当下关注和研究的焦点问题之一。作为光伏发电系统核心设备之一的光伏并网逆变器,当下对其的研究焦点不仅限于对其输出电能的优化,更将效率优化作为追求目标。无变压器光伏并网逆变器无需变压器隔离作用,减小了系统体积、降低了成本、提高了效率,具有很大的研究价值。由于光伏电池板存在对地寄生电容,在没有变压器的情况下,电网与光伏发电系统之间失去了电气隔离作用,形成共模电压回路。共模电压的高频振荡会带来较大的漏电流,不仅造成入网电流畸变,还有可能带来设备损害、人员伤亡,因此必须严格控制漏电流的大小。因此漏电流的抑制成为研究无变压器光伏并网逆变器的关键问题之一。基于调制的漏电流抑制方法无需添加元器件,无需改变电路结构与控制器设计,受到国内外研究人员的广泛关注。本文将分别研究两电平和三电平无变压器光伏并网逆变器基于调制的漏电流抑制方法。为了更好的分析抑制漏电流的原理,对三相光伏逆变器的漏电流模型进行了小信号建模,从其激励源、环路阻抗和传统调制三方面分析了漏电流产生的原理,明确各项电气参数与寄生参数对漏电流的影响。针对两电平无变压器光伏并网逆变器的漏电流问题,文本着重分析了两类典型的调制算法,AZSPWM和RSPWM抑制漏电流的原理及实现方法,并提出一种基于RSPWM调制的死区共模电压补偿算法,使RSPWM可以应用于带死区的开关驱动下。本文对这两类调制算法的直流电压利用率和输出电压谐波进行了理论分析,并与传统SVPWM调制算法进行了对比,为AZSPWM与RSPWM的工程应用提供了理论参考。针对三电平无变压器光伏并网逆变器的漏电流问题,本文着重分析了三种典型的中矢量调制算法,2MV1Z、3MV120和3MV抑制漏电流的原理和实现方法。中矢量调制算法不仅可以理论上消除漏电流,且对直流侧电压利用率较大,具有很大的研究价值。本文理论分析了三种中矢量调制算法的调制比范围、输出电压谐波、输入电流纹波性能,并对其产生的功率器件损耗进行了仿真分析,为三种中矢量调制算法的工程应用提供了理论参考。本文对所有理论分析提供了仿真验证。
[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.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM464;TM615
本文编号：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.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM464;TM615
【参考文献】
相关硕士学位论文 前1条
1 文家燕;光伏并网逆变器共模电压抑制方法和实验研究[D];合肥工业大学;2012年
，本文编号：2135850
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