The common use of by-pass diodes, to contain power generation losses and to avoid “hot-spot” phenomena in presence of short-term, repetitive and critical partial shadings on a PV-field, is experimentally investigated, for demonstrating that bypass diodes are not the optimum choice. Active distributed maximum power point trackers (DMPPTs) can offer a better solution; nevertheless, they are based on complex circuitries and control algorithms, with a reduced reliability and additional power losses. In this contest, the aim of the paper is to present and discuss experimental results obtained by testing a homemade PV-generator prototype in which only a wisely designed and distributed mini-storage based on commercial rechargeable batteries is introduced, to be employed as a “passive” DMPPT, without any active DC/DC converter. The prototype is also experimented to make a comparative performance analysis (i) without bypass diodes, (ii) with bypass diodes and (iii) by introducing our mini-battery-pack, under identical partial shadings, artificially caused and characterized by different degrees of criticality. Experiments demonstrate that wisely designed distributed mini-battery-packs, based on commercial rechargeable batteries, can effectively operate as a passive DMPPT able to cope with short-term critical partial shadings for avoiding “hot-spot” issues and for guaranteeing a significant improvement of the net generated power together with the conventional storage task.
PV-generators, short-term partial shadings, hot-spot on PV-cells, distributed battery storage, bypass diodes, distributed MPPTSPV-generators, short-term partial shadings, hot-spot on PV-cells, distributed battery storage, bypass diodes, distributed MPPTS
 Zhang Z, Wohlgemuth J, Kurtz S. (2013). The thermal reliability study of bypass diodes in photovoltaic modules. 2013 Photovoltaic Module Reliability Workshop, February 26‐27. Golden, Colorado. NREL/PO‐5200‐58225.
 Kim KA; Krein PT. (2015). Re-examination of photovoltaic hot spotting to show inadequacy of the bypass diode. IEEE Journal of Photovoltaics 2015. 5: 1435–1441. https://doi.org/10.1109/JPHOTOV.2015.2444091
 Kurtz S, Whitfield K, TamizhMani G, Koehl M, Miller D, Joyce J, Wohlgemuth J, Bosco N, Kempe M, Zgonena. (2011). Progress in Photovoltaics: Research and Applications T. Evaluation of High-temperature exposure of Photovoltaic Modules 19: 954–965. https://doi.org/10.1002/pip.1103
 Daniele Rossi, Martin Omaña, Daniele Giaffreda, Cecilia Metra. (2015). Modeling and detection of hotspot in shaded photovoltaic cells. IEEE Transactions on Very Large Scale Integration (VLSI) Systems 23(6). https://doi.org/10.1109/TVLSI.2014.2333064
 Silvestre S, Boronat A, Chouder A. (2009). Study of bypass diodes configuration on PV modules. Elsevier Applied Energy 86(9): 1632-1640. https://doi.org/10.1016/j.apenergy.2009.01.020
 Olalla C, Maksimovi´c D, Deline C. (2018). Mitigation of Hot-Spots in Photovoltaic Systems using Distributed Power Electronics Energies 11(4): 726. https://doi.org/10.3390/en11040726
 Patel H, Agarwal V. (2008). Industrial electronics, maximum power point tracking scheme for PV systems operating under partially shaded conditions. IEEE Trans. 55(4): 1689–1698. https://doi.org/10.1109/TIE.2008.917118
 Pilawa-Podgurski Roberto CN, David J. Perreault (2013). Power electron, submodule integrated distributed maximum power point tracking for solar photovoltaic applications. IEEE Trans. 28(6): 2957–2967. https://doi.org/10.1109/TPEL.2012.2220861
 Shibin Qin, Robert CN, Pilawa-Podgurski, Sub-Module. (2013). Differential power processing for photovoltaic applications. Twenty-Eighth Annual IEEE Applied Power Electronics Conference and Exposition (APEC) p. 27. https://doi.org/10.1109/APEC.2013.6520193
 Luo HY, Wen HQ, Li XS, Jiang L, Hu YH. (2016). Synchronous buck converter based low-cost and high-efficiency sub-module DMPPT PV system under partial shading conditions. Elsevier, Energy Conversion and Management Journal 126(15): 473–487. https://doi.org/10.1016/j.enconman.2016.08.034
 Khan W, Xiao. (2017). Review and qualitative analysis of submodule-level distributed power electronic solutions in PV power systems. Elsevier Renewable and Sustainable Energy Reviews 76: 516-528. https://doi.org/10.1016/j.rser.2017.03.073
 Carbone R, Maiolo GA. (2017). Maximizing benefits of batteries in residential grid-connected PV-plants subject to partial shading. Proceedings of the 6-th International Conference on Clean Electrical Power (ICCEP). https://doi.org/10.1109/ICCEP.2017.8004785
 Vitelli M. (2014). Progress in photovoltaics: Research and applications, On the necessity of joint adoption of both distributed maximum power point tracking and central maximum power point tracking in PV systems. Wiley- Blackwell 22(9): 283–299. https://doi.org/10.1002/pip.2256
 Ramos-paja CA, Saavedra-montes AJ, Vitelli M. Dyna R. (2013). Distributed maximum power point tracking with overvoltage protection for PV systems (178): 141-150. Medellin, April 2013. ISSN 0012-7353. Freely available on the web at: 2346-2183. https://revistas.unal.edu.co/index.php/dyna/article/view/30596/44292
 Alonso R, Roman E, Sanz A, Santos VEM, Ibanez P. (2012). Analysis of inverter-voltage influence on distributed MPPT architecture performance. IEEE Transactions on Industrial Electronics 59(10): 3900-3907. https://doi.org/10.1109/TIE.2012.2189532
 Carbone R. (2009). IEEE International conference on clean electrical power, grid-connected photovoltaic systems with energy storage. Capri - Italy. https://doi.org/10.1109/ICCEP.2009.5211967
 Xu CY, Xie CJ, Jiang F, Zhao JY. (2016). Design and implementation of the power battery management system of photovoltaic power generation based on bi-directional DCDC equalization control. IIETA Modelling, Measurement and Control A. 89(1): 156-172.
 Jossen A, Garche J, Sauer DU. (2004). Operation conditions of batteries in PV applications. Solar Energy 76(6): 759-769. https://doi.org/10.1016/j.solener.2003.12.013