Photovoltaic Hot-Spot Detection for Solar Panel Substrings Using AC Parameter Characterization
Photovoltaic Hot-Spot Detection for Solar Panel Substrings Using AC Parameter Characterization
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DOI：
10.1109/tpel.2015.2417548
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发表时间：
2016-02-01
影响因子：
6.7
通讯作者：
Krein, Philip T.
中科院分区：
文献类型：
--
作者：
Kim, Katherine A.;Seo, Gab-Su;Krein, Philip T.
热点是光伏（PV）系统中的一个问题，其降低面板功率性能并加速电池退化。在当今的系统中，旁路二极管用于减轻热点，但它不能防止热点或其引起的损坏。本文提出了一种主动热点检测方法来检测一系列光伏电池内的热点，使用交流参数表征。APV电池由串联、并联电阻和并联电容组成，它们受偏压、光照和温度的影响。实验结果表明，当PV串处于最大功率点跟踪控制下时，单个电池中的热点导致电容增加和直流阻抗增加。电容变化可通过测量10-70 kHz频率范围内的交流阻抗幅度来检测。通过监测容性区域中的一个高频测量值和直流阻抗区域中的一个低频测量值，可以检测到由于热点引起的阻抗值变化。或者，直流阻抗也可以使用直流工作点测量来计算。所提出的热点检测方法可以集成到一个直流-直流电源转换器，在面板或子面板级操作。
Hot spotting is a problem in photovoltaic (PV) systems that reduces panel power performance and accelerates cell degradation. In present day systems, bypass diodes are used to mitigate hot spotting, but it does not prevent hot spotting or the damage it causes. This paper presents an active hot-spot detection method to detect hot spotting within a series of PV cells, using ac parameter characterization. APV cell is comprised of series and parallel resistances and parallel capacitance, which are affected by voltage bias, illumination, and temperature. Experimental results have shown that when a PV string is under a maximum power point tracking control, hot spotting in a single cell results in a capacitance increase and dc impedance increase. The capacitance change is detectable by measuring the ac impedance magnitude in the 10-70 kHz frequency range. An impedance value change due to hot spotting can be detected by monitoring one high-frequency measurement in the capacitive region and one low-frequency measurement in the dc impedance region. Alternatively, the dc impedance can also be calculated using dc operating point measurements. The proposed hot-spot detection method can be integrated into a dc-dc power converter that operates at the panel or subpanel level.