Efficiency improvement of non-uniformly-aged PV arrays

Yihua Hu, Jiangfeng Zhang, Jiande Wu, Wenping Cao, Gui Yun Tian, James L. Kirtley

Research output: Contribution to journalArticlepeer-review


The utilization of solar energy by photovoltaic (PV) systems have received much research and development (R&D) attention across the globe. In the past decades, a large number of PV array have been installed. Since the installed PV arrays often operate in harsh environments, non-uniform aging can occur and impact adversely on the performance of PV systems, especially in the middle and late periods of their service life. Due to the high cost of replacing aged PV modules by new modules, it is appealing to improve energy efficiency of aged PV systems. For this purpose, this paper presents a PV module reconfiguration strategy to achieve the maximum power generation from non-uniformly aged PV arrays without significant investment. The proposed reconfiguration strategy is based on the cell-unit structure of PV modules, the operating voltage limit of gird-connected converter, and the resulted bucket-effect of the maximum short circuit current. The objectives are to analyze all the potential reorganization options of the PV modules, find the maximum power point and express it in a proposition. This proposition is further developed into a novel implementable algorithm to calculate the maximum power generation and the corresponding reconfiguration of the PV modules. The immediate benefits from this reconfiguration are the increased total power output and maximum power point voltage information for global maximum power point tracking (MPPT). A PV array simulation model is used to illustrate the proposed method under three different cases. Furthermore, an experimental rig is built to verify the effectiveness of the proposed method. The proposed method will open an effective approach for condition-based maintenance of emerging aging PV arrays.
Original languageEnglish
Pages (from-to)1124-1137
Number of pages14
JournalIEEE Transactions on Power Electronics
Issue number2
Early online date29 Mar 2016
Publication statusPublished - Feb 2017

Bibliographical note

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Funding: FP7 HEMOW and Marie Curie International Outgoing Fellowship


  • maximum power tracking
  • nonuniform aging
  • offline reconfiguration
  • output characteristics
  • photovoltaics (PVs)
  • solar energy


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