Energy efficiency of the PV panels using a MPPT controller with improved search speed: Part I: Modeling of the PV power system under extremum seeking control

In first part of this paper the Maximum Power Point Tracking (MPPT) technique for photovoltaic (PV) panels based on Extremum Seeking Control (ESC) scheme is analyzed. It is important to know how much energy can be harvested from a PV that uses a MPPT controller. In this paper, the ESC schemes are analyzed in the frequency domain. The modified ESC (mESC) and high-order ESC (hoESC) schemes are considered in this study. The mESC scheme is based on a band pass filter (BPF), while the hoESC scheme is based on a series connection of the high pass (HP) and the low pass (LP) filters. Because the BPF topology may be represented as an equivalent series combination of the HP and LP filters, the equivalence of these topologies is shown for the same cut-off frequencies used. The simulations performed shows that the mentioned equivalence is effective. Also, the design condition to obtain the highest value of the search speed for the mESC scheme is shown when the HP cut-off frequency is known.