The Influence of Asymmetric Parameters on Crosstalk between Paralleled SiC MOSFETs

Abstract

SiC (silicon carbide) MOSFETs suffer serious crosstalk challenges in the high frequency power conversion application. To achieve large current capacity, SiC MOSFETs need to be connected in parallel. This paper discloses that the difference of crosstalk mechanisms between paralleled devices due to the asymmetric parameters in driver loop and main power loop. The effects can also interfere with the driver of action devices, leading to different switching characteristics. The mechanisms of the crosstalk between paralleled SiC MOSFETs with asymmetric driver and power loop parameters are modeled in the soft and hard switching. Through the Miller capacitances and Kelvin source connection, the influences of asymmetric source inductances on the current sharing and the asymmetric drain inductances on the gate oscillations become severe. Experimental results are given to validate the analysis. Finally, suggestions are provided for applications with paralleled SiC MOSFETs.