Eliminating Ground Current in a Transformerless Photovoltaic Application
Eliminating Ground Current in a Transformerless Photovoltaic Application
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DOI：
10.1109/tec.2009.2037810
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发表时间：
2010-01
影响因子：
4.9
通讯作者：
Ó. López;F. Freijedo;A. G. Yepes;P. Fernandez-Comesana;J. Malvar;Remus Teodorescu;J. Doval‐Gandoy
中科院分区：
文献类型：
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作者：
Ó. López;F. Freijedo;A. G. Yepes;P. Fernandez-Comesana;J. Malvar;Remus Teodorescu;J. Doval‐Gandoy
对于小功率并网应用，可以使用单相转换器。在光伏 (PV) 应用中，可以移除逆变器中的变压器以降低损耗、成本和尺寸。由于接地寄生电容，无变压器系统中电网和直流电源的电流连接可能会引入额外的接地电流。这些电流增加了传导和辐射电磁发射、注入公用电网的谐波和损耗。接地电流的幅度和频谱取决于转换器拓扑、开关策略以及由接地电容、转换器、交流滤波器和电网形成的谐振电路。本文在不同条件下测量了 1.5 kW 光伏装置中的接地电流，并用于构建仿真模型。该装置包括一串 16 个光伏电池板、一个全桥逆变器和一个 LCL 滤波器。该模型可以研究逆变器注入的谐波对接地电流的影响。
For low-power grid-connected applications, a single-phase converter can be used. In photovoltaic (PV) applications, it is possible to remove the transformer in the inverter to reduce losses, costs, and size. Galvanic connection of the grid and the dc sources in transformerless systems can introduce additional ground currents due to the ground parasitic capacitance. These currents increase conducted and radiated electromagnetic emissions, harmonics injected in the utility grid, and losses. Amplitude and spectrum of the ground current depend on the converter topology, the switching strategy, and the resonant circuit formed by the ground capacitance, the converter, the ac filter, and the grid. In this paper, the ground current in a 1.5-kW PV installation is measured under different conditions and used to build a simulation model. The installation includes a string of 16 PV panel, a full-bridge inverter, and an LCL filter. This model allows the study of the influence of the harmonics injected by the inverter on the ground current.