Evaluation of a Rogowski-based di/dt sensing for temperature monitoring of SiC MOSFET in TO-247 package

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This paper investigates the sensitivity of the current switching rate regarding the temperature. Particularly, the time-related evolution of the di/dt during turn-on transient is examined. For that purpose a Rogowski coil is specifically designed and characterized for current derivative sensing. It is shown that, other than the temperature, the load current, the external gate resistor and the DC bus voltage influence the measured peak positive di/dt. The absolute and relative variation of all these parameters is studied. Experimental results have reveals a different influence level of each parameter and only the load current seems to require a real time acquisition. The gate technology and other manufacturing features also modify the sensitivity while it seems invariant to the current rating