Solar Energy Procedia IUTAM 00 (2014) 000–000 2210-9838 © 2014 The Authors. Published by Elsevier B.V. Selection and peer-review under responsibility ofABCM (Brazilian Society of Mechanical Sciences and Engineering). A hierarchical architecture for increasing efficiency of large 1 photovoltaic plants under non-homogeneous solar irradiation 2 Thanh Ngo Ngoc ab , Eleonora Riva Sanseverino c *, Ninh Nguyen Quang d , Pietro Romano c , 3 Fabio Viola c , Binh Doan Van d , Hoang Nguyen Huy a , Thang Tran Trong a , Quang Nguyen 4 Phung e 5 a Electric Power University, HaNoi, VietNam 6 b Graduate University of Science and Technology, Vietnam Academy of Science and Technology 7 c DEIM, University of Palermo, Palermo, Italy 8 d Institute of Energy Science, Vietnam Academy of Science and Technology 9 e Hanoi University of Science and Technology, HaNoi, VietNam 10 11 12 Abstract 13 Under non-homogeneous solar irradiation, photovoltaic (PV) panels receive different solar irradiance, resulting in a decrease in 14 efficiency of the PV generation system. There are a few technical options to fix this issue that goes under the name of mismatch. 15 One of these is the reconfiguration of the PV generation system, namely changing the connections of the PV panels from the initial 16 configuration to the optimal one. Such technique has been widely considered for small systems, due to the excessive number of 17 required switches. In this paper, the authors propose a new method for increasing the efficiency of large PV systems under non- 18 homogeneous solar irradiation using Series-Parallel (SP) topology. In the first part of the paper, the authors propose a method 19 containing two key points: a switching matrix to change the connection of PV panels based on SP topology; the demonstration that 20 the SP-based reconfiguration method can increase the efficiency of the photovoltaic system up to 50%. In the second part, the 21 authors propose the extension of the method proposed in the first part to improve the efficiency of large solar generation systems 22 by means of a two-levels architecture to minimize the cost of fabrication of the switching matrix. 23 ©2015 Elsevier Ltd. All rights reserved. 24 25 Keywords:Mismatch, Photovoltaic modules, Optimization, Reconfiguration. 26 Nomenclature 27 EI Equalization Index 28 N number of panels 29 i row index 30 I-V current-voltage 31