A fast and accurate maximum power point tracker for PV systems

The paper presents a fast and accurate maximum power point tracking (MPPT) algorithm for a photovoltaic (PV) panel that uses the open circuit voltage and the short circuit current of the PV panel. The mathematical equations describing the nonlinear V-I characteristics of the PV panel are used in developing the algorithm. The MPPT algorithm is valid under different insolation, temperature, and level of degradation. The algorithm is verified using MATLAB and it is found that the results obtained using the algorithm are very close to the theoretical values over a wide range of temperature and illumination levels. The maximum deviation in the maximum power is less than 1.5% for the illumination levels and temperatures normally encountered by a commercial PV panel. The complete derivation of this MPPT algorithm is presented. It is seen that the algorithm is faster than other MPPT algorithms like perturbation and observation (P&Q) and more accurate than approximate methods that use the linearity between voltage (current) at maximum power point and open-circuit voltage (short-circuit current). The block diagram of a buck-boost PV battery charger with the proposed maximum power point (MPP) tracker is given.