Reduction of Switching Losses in IGBT Power Modules

Abstract

The purpose of this work is to study in deep the transition phenomena of IGBTs in order to evaluate different optimization strategies for losses reduction and propose a novel technique. In power applications a particular attention must be taken to such phenomena as commutation losses, overcurrents during the turn-ON and overvoltage at the turn-OFF of the devices. These phenomena are connected to non ideal behavior of real devices and stray circuit parameters. Steep profiles of current lead to large ElectroMagnetic Interference (EMI) and overvoltages, while rapid variations of the voltage can produce phenomena of "latch-up" in single IGBT or unwanted commutations. On the other hand, slow commutations are characterized by low values of dv/dt and di/dt, causing excessive losses in those power application during commutations. Therefore, it is essential to face the issue with opposite requirements at the design stage obtaining optimal tradeoff.