In this paper is proposed an optimization approach, based on optimal utilization of the power harmonics from the probing signal by including a band-pass filter in the feedback loop of the extremum seeking control (ESC) scheme. The ESC is used to track the maximum power point (MMP) of fuel cell power, and presence of the first and second power harmonics in the probing signal assure this tracking capacity. The MPP tracking robustness is improved by including the third power harmonics into the probing signal, given for probing signal amplitude a time adaptive variation depending of third derivate of the fuel cell power. The MPP tracking is demonstrated and the ESC robustness is proved by simulation in case of using a recommended current ripple factor. (C) 2010 Elsevier Ltd. All rights reserved.