A novel global maximum power point tracking algorithm for photovoltaic system with variable perturbation frequency and zero oscillation

By combing the advantages of two widely-used methods together, namely the particle swarm optimization (PSO) and the perturb and observe (PO), this paper develops and discusses a novel GMPPT algorithm with fast tracking speed for different partial shading patterns and zero steady-state oscillation. Three key elements that form the foundation of the proposed algorithm have been discussed: (1) variable perturbation frequency (VPF) to speed up the dynamic tracking speed; (2) PO tracking is used after convergence of PSO to tackle the reinitialization problem of the PSO since PSO is often unable to detect the small change in the PV system; (3) fixed duty cycle is implemented for the steady state with the PO to realize the zero oscillation. Different partial shading patterns and varying irradiance scenarios are used to evaluate the transient as well as steady state operation of the algorithm. Both simulation and experimental results show that the VPF can greatly reduce the duration of the searching interval of the PSO tracking stage while the following PO tracking stage ensure the correct detection of the proposed algorithm for small changes in the PV system and zero oscillation for the steady state operation