The Gate Drive Requirements for New Generation of High Current Low Voltage IGBTs Employed in Motor Converters

This paper presents overview of switching performances and gate driver requirements for low voltage-high current IGBTs used in three-phase hard-switched inverter feeds a three-phase Tesla induction motor. In the last few years there have been dramatic developments in IGBT technology. Every new generation becomes faster and faster, with fall time of collector current less than 100 ns sometimes even 30 to 40 ns. However, faster switching of collector current, especially at current of 200 A or more, introduces the problem of over voltage across IGBT's chip during the turn off transition. In case of overload or short circuit, the peak voltage on IGBT reaches the critical level and IGBT operates in avalanche. As result the device can catastrophically failed in several nanoseconds after blocking collector emitter voltage collapse. Practically, it is very important to understand that the IGBT must not be in avalanche mode even for very short time, 50 to 100 ns. To prevent a catastrophic failure an active gate driver circuit has to be used instead on a standard gate driver with pure resistive gate control