[en] We investigated the AC magnetic response of a YBa₂Cu₃O₇ film with embedded BaZrO₃ nanorods and Y₂O₃ nanoparticles at a static magnetic field H _dc lower than the matching field H _Φ. We proposed a practical formula for the determination of the induced current J during AC susceptibility measurements, which allows us to directly obtain the pinning potential U _c from the characteristics of electric field E versus J. We show that the dynamic critical current J _d induced at the depinning frequency f _d can be experimentally obtained by measuring m ′(T) and m″(T) at different frequencies and amplitudes. It was found that the value of f _d obtained by extrapolation of J to J _d in the PHz domain is much higher than the frequency reported for ordinary YBa₂Cu₃O₇ thin films as determined by microwave impedance measurements. (paper)