Comparative study of variable size perturbation and observation maximum power point trackers for PV systems

Perturbation and observation (P&O) maximum power point tracking (MPPT) algorithms are common in photovoltaic (PV) systems due to its ease of implementation However, operation with fixed size perturbations results in a trade-off between speed of response and maximum power yield in the steady-state. This paper discusses the use of fuzzy logic and non-switching zone schemes for Implementing variable size perturbations for improved transient and steady-state responses The potential performance of four different P&O algorithms is investigated by means of simulations Experimental results are then used to verify how the computational burden of each algorithm and (tie processing speed of a digital signal processor (DSP) affect the performance of each method in a prototype The best performance is achieved with a new strategy called non-switching zones in the V-PV x I-PV plane The power electronics converter operates with duty cycle (D) equal to 0 or 1, depending on which non-MPP region the system operates, pushing the operating point the fastest way possible towards the MPP region, for improved transient response At the MPP region, a reduced Fuzzy P&O MPPT algorithm optimized for small variations around the MPP is used for reduced oscillations and increased power yield Ill the steady-state (C) 2009 Elsevier B.V. All rights reserved.