An Optimized Fractional Nonlinear Synergic Controller for Maximum Power Point Tracking of Photovoltaic Array Under Abrupt Irradiance Change

Abstract

Maximum power point (MPP) tracking algorithms have always been at the forefront in photovoltaic (PV) systems to counter the nonlinearity caused by PV arrays and, thereby, harvest maximum power. There are several MPP trackers, including fixed and variable step size. The application of a fixed step-size MPP tracker leads to steady-state power oscillations around MPP. On the other hand, a conventional variable step-size MPP tracker employs a constant multiplying factor to increase the convergence rate; however, its response is found to be sluggish under PV parameters’ uncertainties. Therefore, in this article, an optimized fractional nonlinear synergetic controller (FNSC) driven MPP tracker is proposed to meticulously detect the true MPP. The proposed optimized FNSC provides a large dynamic range and ensures minimal sustained power oscillations around MPP even under unequal irradiances. The algorithm based on fractional calculus utilizes macrovariables for improving the performance of the proposed FNSC under steady-state and dynamic operating conditions. The effectiveness of the proposed optimized FNSC is verified using OPAL-RT (OP5700). The outcomes of this study validate the practicability of an FNSC-driven MPP tracker to guarantee less MPP tracking time. The MPP tracking time recorded with the proposed FNSC during steady-state and dynamic conditions is less than 21.80 and 20.80 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ms</i> , respectively. Besides, it guarantees 99.7% tracking efficiency and, thereby, outperforms the existing MPP trackers.