Gate Voltage-Based Active Thermal Control of Power Semiconductor Devices

Active thermal control (ATC) is popularly used for the reduction of junction temperature swings and for enhancing the reliability of power semiconductor devices (PSDs). Gate voltage variation has the potential to be an effective method for ATC by manipulation of power loss in the PSD. However, gate voltage variation in the ohmic region of static
I-V
characteristics does not change the power loss in PSD significantly. To address this challenge, this article proposes an ATC technique based on gate voltage variation in the saturation region of PSD. With the proposed controller, a wide range of power loss manipulation is achieved. Moreover, it avoids false triggering of desaturation protection through a suitable selection of gate voltage. The relationship between gate voltage and power loss in PSD is derived and found to be nonlinear in nature. The proposed controller compensates for this nonlinearity to achieve smooth control over the power loss in PSD. The simulation and experimental validation of the proposed controller are carried out on a laboratory prototype of a dc–dc buck converter for battery charging application. Using the proposed controller, a lifetime improvement of 43% is estimated for a typical mission profile.