Mitigation of Grid Harmonics Using Active Filters with Adaptive Energy Valley Optimization (AEVO) Control Techniques

Many nonlinear devices are linked to the power grid as the fast development of the power electronics sector causes serious harmonic pollution of the grid voltage. Active Power Filter (APF), which can detect the harmonics at the installation location, is the tool used for the harmonic voltage treatment. While considering the surplus of APF active devices to guarantee effective and stable operation of APF, the harmonic sources at each node will change with time and need the injection of fresh harmonic compensation commands. This work intends to offer a dynamic adjustment approach of distributed harmonic compensation based on the computation model of active device margin of APF. First, for certain harmonic combinations, the APF active device loss and injection temperature model is developed to compute in real time whether the harmonic injection command satisfies the active device margin. Furthermore, the Adaptive Energy Valley optimization method is applied to derive new harmonic injection commands for the power grid with harmonic source changes, which on one hand lowers the total voltage harmonic distortion rate of the power grid, and on the other hand satisfies the active device margin to guarantee stable operation of APF. The results demonstrate a significant reduction in Total Harmonic Distortion (THD) from 26.16% to 0.73%, satisfying IEEE-519 standards. Compared with conventional PI and SRF controllers, the proposed method achieves faster convergence, improved dynamic response, and enhanced robustness under unbalanced load conditions.