Several techniques for tracking MPP have been proposed, as described in Section I. Two algorithms are commonly used to track the MPPT - the P&O method and IncCond method.
The P&O method has been broadly used because it is easy to implement. Figure 3 presents the control flow chart of the P&O algorithm.
The MPP tracker operates by periodically incrementing or decrementing the solar array voltage. If a given perturbation leads to an increase (decrease) the output power of the PV, then the subsequent perturbation is generated in the same (opposite) direction. In Fig. 3, set Duty out denotes the perturbation of the solar array voltage, and Duty+ and Dutyrepresent the subsequent perturbation in the same or opposite
direction, respectively.