Closed-Loop dv/dt Control of SiC MOSFETs Yielding Minimal Losses and Machine Degradation

Michael Laumen, Robert Kragl, Christoph Lüdecke, Rik W. De Doncker

Abstract

Inverters with fast-switching silicon-carbide (SiC) MOSFETs enable great power densities and low losses. However, fast voltage transients increase the stress on components that are connected to the inverter, e.g., electrical machines or transformers. State-of-the-art inverters limit the output voltage rise through filters or higher gate resistances, both leading to increased losses. This paper introduces an active gate driver that is able to influence the switching behavior of the SiC MOSFET to limit the voltage transient while allowing low losses. In contrast to conventional approaches, a measurement circuit provides feedback to the control to allow online adaption of the switching pattern.