Limits of Incremental Conductance for determining the Maximum Power Point under rapidly changing irradiance and an alternative technique based on fast scanning

In Photovoltaic (PV) energy systems, Maximum Power Point Tracking (MPPT) is essential in order to efficiently use the solar energy converted. There are many MPPT algorithms. Incremental Conductance (IncCond) is a popular algorithm which is widely used for rapidly changing atmospheric conditions. It is shown that it has no significant increase in convergence speed compared with the most popular empirically based Perturb and Observe (P&O) methods. In this paper, an alternative is proposed to track the MPP under rapidly changing atmospheric and partial shading conditions. In response to a sudden change in radiation from 100% to 30%, this method can converge to the MPP in 20ms. This is the fastest convergence time reported to date, which also has the capability of finding the global peak under partial shading conditions. The ultimate limit of how fast any MPPT algorithm can converge is also discussed.