The Practical Use of SiC Devices in High Power, High Frequency Inverters for Industrial Induction Heating Applications

Induction welding and high frequency hardening are the two most straightforward applications in induction heating for the power inverter. Practical industrial welders require at the same time power levels up to 1 MW while frequencies are in the range between 200-500 kHz, depending on the characteristics of the tube to be weld, while hardening power supplies require power levels up to 400 kW with frequencies in the range up to 200 kHz but with an extreme high number of power cycles. Si-IGBT as well as Si-MOS technologies are normally used in today's induction heating converters, but the new SiC devices offer important benefits, especially in the higher frequency ranges, making this new material very attractive for high power, high frequency induction heating inverters. The paper aims to give practical technical considerations, based on experimental results, for the realistic use of SiC devices in resonant inverters for this type of industrial material processing application.