An Active Harmonic Filter Based on One-Cycle Control

Abstract

The widespread usage of load compensators for carrying out harmonic and reactive power compensation is constrained by cost and poor efficiency due to switching losses. Hence, it is customary to employ active harmonic filters for harmonic compensation only, while traditional methods comprising of thyristor-switched capacitors are used to carry out reactive power compensation. Load compensators based on one-cycle control (OCC) have gained considerable significance as they do not require the service of a phase-locked loop to synchronize with the utility grid. However, existing OCC-based load compensators do not have the capability to differentiate between the fundamental reactive component and harmonic components of the load currents. Hence, they cannot be employed for harmonic compensation alone as they end up compensating for reactive current as well, leading to an increase in the converter rating. In order to overcome the aforementioned limitation, an OCC-based shunt harmonic filter which is capable of compensating only the harmonic components of the load current is proposed in this paper. The viability of the proposed scheme is confirmed by performing detailed simulation studies and experimental validation.