Smart impedance: a new way to look at hybrid filters

Abstract

Smart impedance is a new way to look at hybrid active power filters. As originally proposed in the literature, hybrid active filters were presented to improve the physical limitation of tuned passive filters. A new conditioner named smart impedance is proposed to eliminate the need of passive filter tuning procedure, the whole tuning process is performed electronically. The proposed topology is able to manipulate the displacement power factor and perform multiple frequency harmonic current mitigation at the same time. In weak systems, where the source impedance is not negligible, like in smart grids, smart impedance guaranties the voltage regulation and stability. The smart impedance control strategy uses proportional resonant controller, which allows phase-locked loop-less power system synchronization. Smart impedance system is composed of an active converter, a coupling transformer, and a capacitive unit, arranged as three phase or single phase equipment.