Quasi-passive filter for harmonic filtering

To overcome the limitations of conventional shunt passive filters, a quasi-passive filter has been proposed in this paper. It comprises of a parallel and series tuned LC tank circuit. Unlike the conventional shunt passive filter, the quasi-passive filter utilizes a large value ac capacitor. Unipolar dc capacitors and power semiconductor devices are used to realize the large value ac capacitor. The operation of the quasi-passive filter is simple and it does not require the complex control methods of active power filters. The proposed quasi-passive filter is verified through analysis and simulation.