Tracking the global maximum power point of a photovoltaic system under partial shading conditions using a modified firefly algorithm

Under partial shading conditions, the power–voltage (P-U) curve may exhibit multiple local maxima. This makes it challenging to track the global maximum power point (GMPP). Additionally, in such conditions, conventional maximum power point tracking (MPPT) methods cannot be used to extract the GMPP. This paper describes a modified firefly algorithm (MFA) that can rapidly and accurately extract the GMPP under partial shading conditions. The algorithm introduces the concepts of the global and local firefly densities during each iteration, and devises two elimination mechanisms to adaptively adjust the firefly population. The proposed method is compared with the traditional MPPT algorithms under four different partial shading conditions. Simulation results demonstrate that the MFA can immediately and accurately track the global maximum under the partially shaded conditions, and that the proposed method outperforms conventional techniques in terms of tracking efficiency and speed.