A quasi passive filter for power quality improvement

Harmonic related problems in the electric utility are on the rise due to the proliferation of nonlinear power electronic industrial and domestic loads, which are prerequisites for energy efficiency. Passive, active and hybrid filters are countermeasures against these problems. To overcome the limitations of these filters, a simple and cost effective quasi-passive filter (QPF) topology is proposed in this paper. It comprises of a parallel and series LC tank circuit. The circuit utilizes large value AC capacitor. DC capacitors and power semiconductor devices are used to realize this capacitor.