Digitally Controlled Gate Current Source-Based Active Gate Driver for Silicon Carbide MOSFETs

Silicon carbide (SiC) MOSFETs are viable alternatives for silicon (Si) insulated-gate bipolar transistors (IGBTs). However, direct retrofitting of SiC MOSFETs in Si IGBT-based converters is not feasible due to the presence of a higher amount of parasitic inductance. A large voltage and current overshoot along with oscillation are noticed in such attempts as SiC MOSFETs switch very fast. An active gate driver (AGD) can meet the conflicting requirements of faster switching speed and lower overshoot and ringing. A switched current source-based AGD is designed and extensively tested in a 50-kVA voltage source inverter made with SiC MOSFET power modules. The control methodology is discussed and the experimental results are presented in this article.