Searching of the extreme points on photovoltaic patterns using a new Asymptotic Perturbed Extremum Seeking Control scheme

The features of new Asymptotic Perturbed Extremum Seeking Control (aPESC) scheme have been analyzed in this paper. The proposed aPESC scheme is able to find the extreme points on multimodal patterns generated by a photovoltaic (PV) array under Partial Shading Conditions (PSCs). Besides the Global Maximum Point (GMP), other Local Maximum Point (LMP) close to the GMP could be useful to be known in specific engineering applications in order to use a global (optimal) or local (suboptimal) optimization solution. The tuned parameters (the dither gain k(2) and the loop gain k(1)) of two adaptive control loops of the aPESCH1 scheme proposed here (instead of one for the classical aPESC schemes) will be designed to locate and track accurately the GMP and LMPs on different multimodal PV patterns. The constraining rules related to scanning limits and closed loop stability will set the designed range for the tuned parameters. A general procedure to design the dither gain k(2) to locate the GMP will be shown. The LMPs will be found by fine-tuning of gain k(2). The loop gain k(1) will be designed considering the stability's limit of the closed loop containing the PV system dynamic and aPESCH1 scheme. The performance obtained was highlighted using different PV patterns and a PV system implemented in MATLAB/Simulink software (R). (C) 2017 Elsevier Ltd. All rights reserved.