Fast tracking electrosurgical generator using GaN switches

Electrosurgery involves the use of high-frequency (typically 100-500 kHz) alternating current (AC) 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 multi-phase buck topology using GaN switches. Experimental results are given for a 4-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 180 Ω to 3600 Ω load.