Current-Limiting Control Strategy for Indirect-Current-Controlled Active Power Filter

Indirect-current-controlled active power filter (APF) is preferable compared with the direct-current-controlled APF due to its simpler structure and its direct regulation of the grid current. However, unlike direct current control, indirect current control does not have explicit current reference posing difficulty on current limiting operation. This letter proposes a current-limiting control strategy for indirect-current-controlled APF. By adding harmonic resonant controllers into the closed-loop control of the APF's output current, the harmonic components of output current can be smaller than that of the nonlinear load's current. The effectiveness of the proposed current-limiting control is verified by experiments.