The estimation of interharmonics by group frequencies

In this paper, an innovative concept, group frequency (GF), is proposed to facilitate the analysis of power system interharmonics as well as conventional integer harmonics. The concept is applied in the analysis of load currents of integral cycle controllers (ICCs) and other controlled power applications. A GF can be generalized for the analysis of load currents or voltages of other power devices. One of the advantages of the GF is that a large number of frequency components of a load voltage or current are simplified to a few frequency components without significantly changing the power quality impact of the load current or voltage.