This Letter describes a method to quantify online and in real-time, the level of degrading of the series parasitic resistance R s of a photovoltaic (PV) panel. This method aims to obtain the herein proposed M-factor, which results from the calculation of the slopes of the I–V curve in the boundaries of its maximum power-point. For this purpose, the slight modification of the maximum power-point tracker controller’ perturb and observe algorithm is required. This procedure can be easily integrated into its firmware with no additional costs. The M-factor calculation is performed instantaneously and since no disconnection is required, no significant power losses are produced.

中文翻译：

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PV 电池板 R 的寄生电阻退化估计通过 MPPT 控制器修改操作：M 因子计算

这封信描述了一种在线实时量化光伏 (PV) 面板串联寄生电阻 R s 退化程度的方法。该方法旨在获得本文提出的 M 因子，该因子是通过计算 I-V 曲线在其最大功率点边界处的斜率得出的。为此，需要对最大功率点跟踪器控制器的扰动和观察算法稍作修改。此过程可以轻松集成到其固件中，无需额外费用。M 因子计算是即时执行的，由于不需要断开连接，因此不会产生显着的功率损耗。