Evaluation of the off-state base-emitter voltage requirement of the SiC BJT with a regenerative proportional base driver circuit and their application in an inverter

A strong candidate device for use in high-efficiency and high-density power converters is the SiC bipolar junction transistor, which requires a continuous gate (base) current to maintain its on-state. A base driver circuit with regenerative collector current feedback using a current transformer, and a negative off-state base-emitter voltage is presented in this article. The off-state base-emitter voltage required to prevent simultaneous conduction of a commercially available device when subjected to dv/dt's is assessed. The device is then utilized in a three-phase dc-To-Ac power converter where the efficacy of using the proposed base driver is evaluated. The off-state base-emitter voltage used is informed by the dv/dt tests. The converter is supplied from a 600-V dc rail, switches at 50 kHz and supplies a 4.1-kW load at a modulation index of 0.9. An efficiency of 97.4% was measured.