Frequency-Domain Method to Determine Validity of the Fundamental Harmonic Approximation

The fundamental harmonic approximation (FHA) sometimes loses precision in resonant circuits and wireless power transfer (WPT) systems, and the theoretical boundaries for the validity of the FHA are not well determined. We present a method for determining the boundaries of the FHA’s validity using rapid and easily-interpreted frequency-domain analysis. We demonstrate the method with series-series (S-S) and double-sided inductor-capacitor-capacitor (DS-LCC) wireless power transfer topologies. In addition to validating the method, we demonstrate its usefulness by identifying that the FHA can be applied over a broader range in the DS-LCC topology. This analysis is validated through a 600 W simulation and experimental setup.