Hybrid and Series Active Filters

The series active filter acts like a dual device for the shunt active filter. The shunt active filter has a voltage source at the source side and a current source at the load side, where the current source includes harmonic currents that have to be compensated by the shunt active filter. In some cases, the combination of a voltage source and its impedance at the source side is considered as a current source. As a result, the series active filter operates as a dual circuit of the shunt active filter from a theoretical point of view. Comprehensive research has been conducted on hybrid active filters for harmonic filtering, harmonic damping, harmonic isolation, and harmonic termination. This chapter presents a transformer less hybrid active filter integrated into a medium‐voltage motor drive for energy savings. It discusses the stability of the ac/dc power conversion system characterized by integration of a series active filter with a double‐series diode rectifier.