Hybrid active ﬁlter; harmonic extraction; multiple synchronous reference frames; power quality.
A Shunt Hybrid Active Filter (SHAF) is an attractive option for realizing low-cost harmonic compensation solutions. This paper proposes a SHAF with multiple harmonic compensation capability using a single Voltage Source Inverter and reduced sensor count. This strategy is apt for harmonic ﬁltering solutions where low cost is the exclusive priority. In this paper, a new estimation approach is proposed to obviate requirement of a large number of sensors. Multiple Synchronous Reference Frames (MSRF) and low pass ﬁlters are used to measure 5th and 7th harmonic components separately from load as well as ﬁlter currents. Individual current controllers are designed for the 5th and 7th harmonic currents. Control is realized in the synchronously rotating, orthogonal (dq) reference frame. Performance of the controller is validated through simulation, using realistic plant and controller models. Experimental results are provided to corroborate the analytical and simulation results.