PRBSを用いた電力変換器による太陽電池のインピーダンス測定手法

抄録

The output power of solar panels may decrease by degradation due to long-term usage and surface contamination. Methods to detect these problems are necessary for photovoltaic generation to be more widespread. AC impedance methods are used for electrochemical devices to inspect the inside situation of solar panels. In this study, we applied an ac impedance method to solar panels, which have some merits compared with the traditional methods. We added a small ac signal to the duty of a dc-dc converter to implement the ac impedance method. The small ac signal was a white noise generated by a pseudorandom binary sequence (PRBS) such that many frequency points can be measured simultaneously. Unlike traditional methods, this method can examine the solar panels when they are generating power. We measured shaded and nonshaded solar panel impedances and compared with the experimental results. From the results, we can show the potential to distinguish the shaded panel or the unshaded panel based on the difference of the impedance characteristics.