A New Calorimetric Method for Switching Loss Measurement of Power Devices

This paper proposes an alternative calorimetric method to measure the switching losses of power semiconductors using the principle of thermal equilibrium, based on the control of the temperature of an aluminum plate hosting the DUTs as well as heating elements, all placed within the same thermally insulated enclosure. By analyzing the change in power dissipation of the heating element, the losses of the power device can be determined. The proposed solution features: accurate estimation of device conduction losses without the need to know the internal junction temperature; simplified calibration phase to partially compensate for thermal setup non idealities; no need for a precise thermal model of the measurement setup; switching loss measurement under actual operating conditions, including soft-switching and hard-switching conditions. Experimental measurements on SiC MOSFETs show the properties of the proposed approach.