Frequency-Modulation Controlled Load-Independent Class-E Inverter

This paper proposes the frequency-modulation (FM) controlled load-independent class-E inverter, which has robustness against simultaneous variations of the load and the components in the output resonant filter. The main idea is to apply the FM control of the output-voltage regulation to the load-independent class-E inverter. By applying that, the proposed inverter can keep the phase shift between the driving signal and the output voltage constant without using any time information. As a result, the proposed inverter can maintain the constant output voltage and high power-conversion efficiency operation at high frequencies despite the load variations and the component tolerances in the output resonant filter. We give analytical expressions of the proposed inverter and quantitative evaluations. Additionally, an experimental prototype of the proposed inverter was implemented. The theoretical and experimental results showed the validity and effectiveness of the proposed inverter. The implemented inverter achieved 95% efficiency with the 5.7 W output and 1-MHz operating frequency at the rated operation.