Modern PV arrays are generally designed with bypass diodes to avoid damage. However, such arrays exhibit multiple peaks in their P-V characteristics under partial shading conditions. Owing to the limitation in the abilities of conventional maximum power point tracking algorithms in such cases, the application of other optimisation algorithms has been explored. This study proposes a modified particle velocity-based particle swarm optimisation (MPV-PSO) algorithm for tracking the global power peak of the multiple peak P-V characteristics. The MPV-PSO algorithm is both adaptive and deterministic in nature. It eliminates the inherent randomness in the conventional PSO algorithm by excluding the use of random numbers in the velocity equation. The proposed algorithm also eliminates the need for tuning the weight factor, the cognitive and social acceleration coefficients by introducing adaptive values for them which adjust themselves based on the particle position. These adaptive values also solve problems like oscillations about the global best position during steady-state operation and particles getting trapped in local minima. The effectiveness of the proposed MPV-PSO algorithm is validated through MATLAB/Simulink simulations and hardware experiments.

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Nonuniform irradiation of a photovoltaic (PV) source, consisting of series-connected modules with bypass diodes, results in multiple peaks in the power-voltage characteristics. This makes the maximum power point tracking (MPPT) difficult because the conventional MPPT algorithms can only deal with single power peak characteristics. This paper proposes a novel distributed MPPT (DMPPT) scheme based on an interleaved single-ended primary inductor converter (SEPIC) converter configuration for compensating the mismatch in characteristics of series-connected PV modules. The proposed scheme obviates the need for bypass diodes across the modules, resulting in single-peak power-voltage characteristics. The proposed DMPPT circuit is derived from an interleaved SEPIC converter that works on the "return energy" concept. The proposed configuration equalizes the voltages across PV modules of the string, resulting in their operating close to its maximum power point. Discontinuous conduction mode of operation is implemented, obviating the voltage-sensing requirements across modules, eliminating the reverse recovery loss of diodes and the turn-on loss of the main switch. The proposed DMPPT scheme uses a simple circuit with reduced control complexity and needs only a few passive elements and only one switching device, compared with the existing DMPPT schemes. The theoretical claims are validated with simulations and extensive hardware experiments. Index Terms-Discontinuous conduction mode (DCM), distributed maximum power point, interleaved single-ended primary inductor converter (SEPIC), nonuniform irradiation, photovoltaic (PV), power-voltage characteristics. . His research interests include maximum power extraction techniques for photovoltaic (PV) arrays under partially shaded conditions, distributed maximum power point tracking, and microinverter configurations. He also works on the control of solar PV power conditioning units for grid-connected and standalone applications.

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