DSP based control and soft switched mode power conversion realizes smart and portable N-channel RF generator for surgical ablation

This paper presents the design and implementation of digital control and resonant switched mode power conversion for realization of a n-channel radio frequency (RF) generator for surgical ablation. This implementation has several key contributions to RF ablation applications and results in production of a smart and portable n-channel RF generator. The major contributions are: cost reduction, power/weight and power/volume ratio increments, improved performance (high efficiency and low total harmonic distortion (THD)), expandable channels (electrodes) capability, in-phase n RF outputs independent of n different loads (body tissue), ultra fast fault detection and protection, and real time communication with host computer and data logging. Simulation and experimental results demonstrate the feasibility of the proposed technique and control schemes. A 5-channel RF generator prototype is designed, made and evaluated. Each RF channel can be controlled in two modes, temperature and/or power modes, and is independently capable of delivering up to 20W per channel pure sinusoidal RF power at 480 kHz to patient tissue. All control inputs such as ablation time, control mode (temperature vs. power), temperature and power set points, log file name, etc., are entered by a graphical user interfaced (GUI) host laptop. All of the feedback data from catheter probe tips, such as RF voltage, RF current, phase, tissue temperature, tissue impedance, RF power, etc., are logged automatically back into an excel file and in parallel, the key ones are graphically demonstrated in real time. The validity of the proposed design approach is verified with an experimental prototype.