Load-Insensitive Design of Class E Inverter Based on Inequality Constraints

This paper aims at investigating load insensitivity in order to achieve high conversion efficiency across a wide range of loads, departing from the conventional approach of optimizing a classical single-switch resonant converter for a specific load resistance to attain ideal soft switching. This design involves introducing a non-ideal soft switching condition, i.e., partial zero voltage switching, which is mathematically expressed as an inequality constraint. By leveraging the impedance model, the study explores the full design potential of the inverter, allowing for a more balanced trade-off between efficiency and load insensitivity. The experimental results demonstrate the operation of a 1-MHz inverter, maintaining an efficiency over 96% as the load resistance varies within the range of [10, 20] Ω and [10, 60] Ω.