Control of a SiC 2.5 MHz resonant full-bridge inverter for inductively driven plasma

The electronic ballast of an inductively driven plasma faces a mostly inductive, variable load impedance. The SiC full-bridge inverter uses the inductive behavior to achieve zero-voltage-switching and a switching frequency of 2.5 MHz, at 3.9 kVA and 764W in the plasma. The control is realized on a modern, small TI Piccolo microcontroller with a high-resolution PWM module and compensates for the variable load impedance. We present design and experimental results of a 2.5 MHz inverter for inductively driven plasma without the need for a large FPGA controller.