The quality and performances of the compensation of harmonic currents depends strongly on the performances of the identification blocks of control side of the photovoltaic generators used as active filters. Then, the use of harmonics identification methods is not valid because the network voltage must be sinusoidal and balanced, which is not the case in practice. Hence, to make the application of the identification methods of harmonic currents versatile and for any voltage form, we use the detection system of the fundamental component of the direct voltage. In this paper, a comparison between the conventional method used for extracting the direct component of the network voltage which is based on the phase-locked loop (PLL) and the new approach based on a multivariable extraction filter. Finally, simulation results show that the proposed multivariable filter may better work even if the network voltage is (perturbed and unbalanced). Furthermore, this filters permits to generalize the use of identification methods for filtering the different perturbations of active and reactive current. (C) 2015 The Authors. Published by Elsevier Ltd.