Modeling of a RF Surgical Generator based on a Push-Pull Oscillator

Abstract

To reduce manufacturing costs, a new simple radio frequency (RF) surgical generator based on a push-pull oscillator is developed for cutting tissue. In order to systematically design and test feedback controllers keeping the generator’s output voltage constant, we will present two different models of the considered RF generator. The first one is a nonlinear state space model derived using the generator’s equivalent circuit diagram and Kirchhoff’s laws and the second one is a Hammerstein model. The models are based on physical principles and are successfully validated on a generator prototype, ensuring a good match with the static and dynamic behavior of the considered RF generator. The obtained state space model is well suited to simulate the RF generator, while the Hammerstein model is appropriate to design controllers for the generator’s output voltage.