Performances Assessment of Very High-Frequency Class E Inverters Based on a Load-Oriented Generic Design Method

Class E inverters are widely used in very high-frequency power converters due to their ease of driving, their high efficiency, and their low component count. A generic design method applicable to arbitrary load impedance, output power, and switching frequency is presented. The newly introduced visual tool is a support for designers to identify an optimal operating point. Depending on the application requirements, different operating points can be evaluated in terms of their performances. The method is carried out with three scenarios complying with the same requirements: 40.68 MHz, 50 W, and a 5- $\Omega $ wireless power transfer (WPT) load. The different designs are then compared and three prototypes are implemented and characterized to validate the method. The nonlinear output capacitance of the gallium nitride high electron mobility transistor (GaN HEMT) is entirely functionalized. The attained inverter efficiencies at the nominal operating points are measured between 87.7% and 89.8%.