Novel predictive control of 3-phase LCL-based active power filter

Active power filters (APF) are the most effective solution to compensate harmonic currents of nonlinear loads. Usually, they are connected to the grid via first-order inductive filter L, and in consequence inject to the grid parasitic current ripples caused VSI switching. This serious drawback can be removed by connecting APF´s VSI via LCL filter. Such a solution requires control that overcomes resonance problem and, at the same time, maximizes control dynamics. This paper introduces novel, model based predictive controller for APF with LCL filter, which provides control dynamics limited only by circuit parameters. There are presented simulations and experimental results achieved for 300 kVA power blocks operating in parallel in 1.2 MVA APF system.