LC coupled shunt active power filter (APF): New topology and control method

This paper presents a new structure and control method for three phase four wires LC coupled parallel active power filters (APF) for harmonics cancellation. The main differential point with regard to classical structures, consists of the connection of neutral wire to negative of DC bus in the inverter, thus avoiding the need of split capacitors at the DC bus. The LC coupling and a particular control of the DC voltage at the coupling capacitors allow the use of low voltage at the DC bus and provide a symmetry of the available voltage for the current controller, during t_on and t_off. The paper includes a discussion of the new structure and presents a summary of the control method. Simulation and experimental results are given to show the behaviour of the system, used for harmonics cancellation.