Two-Stage Wide-Output High-Frequency-Voltage Inverter for Electrosurgical Generator

The electrosurgical generator (ESG) is a medical power supply device that utilizes the thermal effect of high-frequency current flowing through the body tissues. It needs to maintain constant output power when the tissue load varies over a wide range during treatment, which means that wide-output high-frequency voltage should be provided by ESGs. Moreover, the frequency of the output voltage had better be stable to ensure a good therapeutic effect. However, most ESGs control the power by adjusting the frequency or the shape of the output voltage. This paper proposes a two-stage structure with a resonant DC/DC converter as the first stage and a class DE resonant inverter as the second stage. Due to the resonant structure, not only do all the semiconductors achieve ZVS operation, but also the converter is suitable for wide-range voltage regulation. The simulation results and the experimental waveforms verify the theoretical analysis and effectiveness.