On the dither persistence in the Extremum Seeking control Part II: Signal harmonics´ persistence for large filtering pass band

In the second part of this paper, the dither persistence on the Extremum Seeking Control (ESC) loop is analyzed. The ESC scheme is usually used on Maximum Power Point (MPP) tracking controller to harvest the energy available from used renewable or green Energy Sources (ES). Two ESC schemes are analyzed in relation with dither persistence on output reference current: (1) the modified ESC scheme (named mESC scheme because is based on band-pass filter BPF use, instead of series connection of the high-pass and low-pass filters such as used in higher order ESC scheme) and (2) its equivalent representation (named EQmESC because is based on modified higher order ESC scheme). The pass band (the cut-off frequency of low-pass filter) is chosen larger than in higher order ESC schemes in both ESC schemes proposed. Thus, dither persistence on the proposed ESC loop is improved. Consequently, the search speed of the extremum increases accordingly. These are shown by mathematical modeling and simulation.