Metaheuristic Based MPPT Control for Solar PV Systems Under Partial Shading Conditions

Partial shading significantly impacts a PV array’s ability to generate power. The array’s modules will produce various row currents.Thus the panels must be modified for row current difference minimization to maximize the power extraction from the PV array. Under uniform insolation, conventional Maximum Power Point Tracking (MPPT) Hill climbing approaches such as Perturb and Observe and Incremental Conductance(INC) can effectively track the maximum power point, but they fail under partial shaded conditions. Physical panel relocation may involve time-consuming operations and extensive interconnection ties. Meta-Heuristic algorithms for effective shadow dispersion is an appealing approach. In this paper, an MPPT control method based on meta-heuristic Grey Wolf Optimization (GWO)is implemented in a Triple Tied (TT) configuration to track the global maximum power point(GMPP) under 5 distinct partial shading scenarios.The performance indices such as mismatch power, fill factor and convergence time of GWO results are compared with INC, Particle Swarm Optimization(PSO) and Horse Herd Optimization(HHO) algorithms. The GWO approach is found to perform better than INC,PSO and HHO in tracking the GMPP with better accuracy and less computational time in all shading conditions.

I. Introduction

With the fast depletion of non-renewable energy sources like oil, coal, and natural gas, as well as significant rise of air pollution in recent decades, need for sustainable and renewable energy supply has become important . Thus, the renewable energy especially solar will play a significant role in future [1]. However, considerable technical and economical obstacles remain in the way of actual solar energy implementation. Technical challenges include intermittency, non-dispachability, low conversion efficiency and seasonality. Economic challenges include high upfront cost, grid parity and high payback [2]. Several factors contribute to the lowering of PV array output [3]. Partial shading is one of the most significant contributors to the loss of output power [4]. The shading is caused due to nearby trees, poles such as telecom towers, tall buildings, bird drops, and clouds passing (dynamic shading). In all weather conditions and seasons, avoiding partial shade of the array is impossible. Many experts have looked into the effects of partial shading on PV systems and possible solutions. PV array reconfiguration is one of the most important solution in this direction. The power-voltage (P-V) and current-voltage (I-V) curves will only have one peak value in ideal conditions. However, the curve will have multiple peaks under partial shading conditions (PSC). As a result, the PV system design must select the appropriate value of control parameters and track the maximum power using MPPT.