Proportional Driver for SiC BJT’s in electric vehicle inverter application

Inhalt:
This paper describes the energy saving potential of base drive units for high-power bipolar junction transistors (BJTs). BJTs are current-controlled devices which lead to high requirements on the base drive circuit: high turn-on current, an on-state-current which is around 3% of the collector current and protections against parasitic turn-on during turn-off. Safety features like desaturation protection, safe startup of the base driver (because of essential large bypass-capacitors) and adapted PWM control strategies have been investigated. Furthermore, application related considerations are made: Especially in inverters for electrical drives with user dependent drive profiles (e.g. for a motor of an electrical vehicle), power savings can be achieved by adjusted base drive circuits and control strategies.