Proportional Integral Finite Set Model Predictive Control for a Transformer-Less Compact Multilevel Active Power Filter

This paper investigates the performance of an advanced nonlinear controller that is applied to a grid connected Multilevel Active Power Filter (MAPF) with the aim of suppressing harmonics generated by a nonlinear load. The MAPF is designed based on Modified Packed U-Cell topology to boost voltage amplitude such that conventional coupling transformer is removed and the dc-link capacitors size is reduced. By providing five-level voltage using MPUC, undesired harmonics are suppressed so that THD level and the inductance size in grid filter are minimized. Balancing the capacitors voltage and tracking the desired grid reference current are the main control objective which have been guaranteed by the proposed Proportional Integral Finite Set Model Predictive Control (PI-FSMPC) technique. In this method, PI generates the current reference based on the capacitors voltage error and FSMPC controls MAPF using the current reference. Experiments and Simulations provided in this paper confirm feasibility and reliability of PI-FSMPC to attain all the control objectives.