Abstract: To address the issue that the traditional hardware phase-locked loop (PLL) ip-iq algorithm cannot achieve the separation of fundamental positive-sequence active and reactive currents, this paper proposes an improved ip-iq detection algorithm based on DFT reconstruction. The DFT algorithm is employed to reconstruct the fundamental voltage and its orthogonal quantity in the αβ coordinate system. By combining the instantaneous symmetric component transformation, the decoupling of fundamental positive-sequence and negative-sequence voltages is realized, providing accurate voltage phase information for the ip-iq algorithm and enabling the detection of fundamental positive-sequence active and reactive currents. Compared with the traditional ip-iq method, the improved algorithm proposed in this paper uses a digital phase-locked loop, which effectively solves the problem of voltage phase tracking under complex power grid conditions and can accurately and quickly extract fundamental positive-sequence active and reactive currents. Finally, the correctness of the algorithm is verified through simulations and experiments.