MPPT of a PV system based on the particle swarm optimization

Under partial shading conditions, it is possible to have multiple local maxima in a photovoltaic (PV) system, but overall there is still only one true maximum power point (MPP) in the system. To track the true MPP, a strategy called variable size of particle swarm optimization (PSO) is developed. The strategy increases the movement step of particles at the initial iteration, and decreases it gradually with iteration. The simulation results showed that the strategy can track the global MPP fast and accurately in PV systems.