Design and Implementation of RF Resonant Inverter With Matching Circuit to Generate Plasma for Possible Endoscopy Sterilization

This research focuses on the design and implementation of an RF resonant inverter with a matching circuit to generate plasma for possible endoscopy sterilization. The circuit topology is a half-bridge inverter with the operating frequency of 13.56 MHz. The soft switching is achieved by the matching circuits and resonant network to reduce switching loss. Conventionally, an RF power amplifier associated with an automatching circuit is used to match the chamber to50 Ω, which will be presented in detail as a reference. Alternatively, the half-bridge inverter is designed to identify the chamber impedance, and therefore, the CLCL matching circuits can be designed to match the chamber. The matching circuits were designed based on chamber-impedance measurement to obtain the first point, and through Smith Chart, one can reach the destination,50 Ω, point by point to determine a set of CLCL component values. The overall system is verified with a 300-W half-bridge inverter using GaN MOSFET switching elements.