An improved perturbation and observation MPPT method of photovoltaic generate system

An efficient maximum power point tracking (MPPT) algorithm is important to increase the output efficiency of a photovoltaic (PV) generate system. The conventional perturbation and observation (PO) MPPT algorithm is impossible to quickly acquire the maximum power point (MPP), and the tracking course is very difficulty under veil weather conditions, and the essential reason is not known the actual values of the n and Io. It is well-known that the different solar cells have different n and Io. Theoretical and simulative results show that a piece of solar cell has same photocurrent under different n and Io conditions. A new combined perturb and observe (PO) method is described in order to acquire the actual n and I. Then an improved PO maximum power point tracking method is described which based on the actual n and Io, and the tracking bound is reduced, and the tracking speed is rapid to compare with the conventional PO method. Furthermore, it is simple and can be easily implemented in digital signal processor (DSP). The simulation results verified the correctness and validity of MPPT method.