Perturb-and-Observe MPPT for a Photovoltaic Module under Changing Irradiance: Effect of the Perturbation Step in Simulation

Maximum power point tracking (MPPT) algorithms let a photovoltaic (PV) module operate near its maximum power under changing conditions. This paper simulates a 60-cell module described by the single-diode model (solved exactly with the Lambert W function; assumed parameters) with a perturb-and-observe (P&O) algorithm running at 100 Hz, under an irradiance profile that falls from 1000 to 400 W/m² and then rises to 800 W/m². For fixed voltage steps of 0.1, 0.5, 1.0 and 2.0 V the tracking efficiency (energy divided by the energy at the true maximum power point) over the 10 s profile was 98.5 %, 99.5 %, 99.4 % and 97.5 %. Small steps gave the best steady-state efficiency (99.99 % at 400 W/m² for 0.1 V) but slow start-up (95 % of maximum power after 0.64 s), whereas large steps converged quickly (0.04 s for 2 V) but oscillated widely around the maximum. A step proportional to |ΔP/ΔV| reached 99.3 %. The converter dynamics are not modelled and the module parameters are assumed. This is a simulation study; all results are outputs of the deposited Python code with assumed parameters. Source code is attached.