ONLINE IGBT JUNCTION TEMPERATURE ESTIMATION WITHOUT THE USE OF A DEDICATED TEMPERATURE ESTIMATION OR MEASUREMENT DEVICE

A number of variations may include a method which may include determining a temperature rise in an IGBT junction without the use of a temperature estimation or measurement device because determination may be made by first determining the power loss due to the conduction losses of the IGBT and power loss associated with switching the IGBT where these losses may be determined by utilizing the saturation voltage of the IGBT, IGBT PWM duty cycle, IGBT switching frequency, fundamental frequency along with a lookup table for the switching energies and the phase current going through the IGBT. The determined power loss may be multiplied by a measured, sensed or obtained thermal impedance from the IGBT junction. Finally, the determined temperature rise of the IGBT junction may be added to a measured, sensed or obtained temperature of the coolant in order to determine the absolute temperature of the IGBT junction.