Fast Tracking Electrosurgical Generator Using Two-Rail Multiphase Buck Converter With GaN Switches

Electrosurgery involves the use of high-frequency (typically 100-500 kHz) alternating current to elicit a clinical response in tissue (e.g., cutting or cauterization) using a plasma arc. Standard electrosurgical generators (ESGs) are based on resonant inverters, which constrain the output frequency and waveshape. This paper describes a fast tracking ESG capable of shaping the output ac waveform over a range of frequencies, thus providing improved flexibility and control in electrosurgery applications. The proposed fast tracking ESG is based on a two-rail multiphase buck topology using GaN switches. Experimental results are given for a four-phase ESG prototype operating from ±250 V with 2-MHz per-phase switching frequency, capable of providing up to 50 W to an arc modeled as a 300-4000 Ω load.