Design of choke inductor in Class-E ZVS power amplifier

This paper presents the following for a Class-E zero-voltage switching (ZVS) power amplifier: (a) design of the choke inductor and (b) theoretical estimation of power losses in the core and a solid round winding. The expressions required to design the core using the Area-Product (Ap) method are provided. The equations for the dc resistance, ac resistance at high frequencies, and dc and ac power losses are provided for the solid round winding. A Class-E ZVS power amplifier with practical specifications is considered. A core with air gap is selected since the choke inductor carries a dc current in addition to the ac component. The gapped core power loss density and power loss are estimated using Steinmetz empirical equation. Simulation results showing the transient analysis and Fourier analysis are given. It is shown that, for the given design, the winding power loss due to the fundamental component is dominant and that due to higher order harmonics can be neglected. In addition, it is also proven that the power loss caused by the dc current component is higher than that by the ac current component, which can be neglected.