Novel Dual P&O MPPT Techniques for Enhancing Power Harvesting

This work deals with the use of two novel techniques for enhancing the maximum power point tracking (MPPT) of a photovoltaic system based on the P&O “Perturb and Observe” strategy. The P&O method is a relatively simple and fast technique, requiring only a small number of sensors; but it is known for its limits under changing atmospheric conditions especially in the case of a rapid one. That causes power losses by the oscillation of the photovoltaic system’s operating point around its optimum position. These losses increase with the step size of the chopper duty cycle. On the other hand, a very small step size will increase the system’s response time even the power losses are reduced, so a compromise must be made between the system speed and power losses. To alleviate this problem, the first dual technique which is a combination between a P&O and INC (incremental conductance) methods is suggested, where a control of voltage and current is needed for greater precision and efficiency. Better results are achieved when viewed from a PPM tracking. Although the power losses recorded persists in steady state, they can be moderated by judicious adjustment of the incrimination step size parameter “Cp”, for that a second novel technique combining a FUZZY LOGIC technique with a P&O (FLC- P&O) is proposed. The dual studied showed after simulation that the dynamic state and the photovoltaic system efficiency were simultaneously improved. This confirms the feasibility and effectiveness of the PPM proposed tracker. The tests carried out showed acceptable performances.