Unbalanced Harmonic Suppression of Three-Level Active Power Filter with Optimal Hybrid Control

Aiming at the increasingly serious harmonic pollution in power system, this paper proposes an optimized harmonic suppression strategy by combining properties of the predictive current control strategy and specific order harmonic suppression algorithm based on active power filter (APF) in a medium-voltage application occasion. Compared with the traditional harmonic suppression algorithm, the proposed algorithm not only realizes the effective compensation from low order harmonics to high order harmonics, but also compensates some specific order harmonics. In addition, the proposed strategy can achieve separation of the negative sequence part from the load current and then compensate it separately under the unbalanced condition. Finally, some experimental results are conducted to verify the correctness and reliability of the proposed algorithm based on a small-scale prototype.