Multiconstraint Design of Single-Switch Resonant Converters Based on Extended Impedance Method

Abstract

The single-switch resonant converter is attractive for low-cost high-frequency power conversion applications. However, the exiting design method needs complicated derivations to meet various practical demands, and it would become impossible as the circuit order increases. This article incorporates the extended impedance method to evaluate the potential designs. The practical demands can be mathematically represented by the inequality constraints. Given the design variables, the proposed design is able to improve the steady-state performance (like the system robustness, voltage gain, load insensitivity, efficiency, current stress, and voltage stress) for the existing resonant converters. A family of Class E inverters is designed to justify the generality and validity of the proposed design. The first case is a classical Class E inverter. The EIM-based design is able to improve the system robustness under 6% parameter variation. The second case is a Class E inverter with resonant input inductor. The EIM-based design is able to offer a wider voltage gain compared to the benchmark method. The last case is a Class E inverter using <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pi $ </tex-math></inline-formula> network. Compared to the previous design approach, the proposed method is able to find a better design point, whose light-load efficiency is improved by 5%.