Abstract: After start of an electric drive system, a controller reduces power output of an inverter responsive to sensed temperature of a power switch of the inverter, sensed current of a power electronics module, sensed DC-link voltage, and thermal impedance parameters of a DC-link capacitor being indicative of an estimated temperature of the DC-link capacitor that is greater than a threshold to maintain DC-link capacitor temperature lower than the threshold.

Abstract: An electric drive system includes a power electronics module (PEM) having a DC-link capacitor and an inverter. A controller reduces power output of the inverter while a sensed temperature of an inverter power switch, a sensed current of the PEM, such as a sensed ripple current of the DC-link capacitor, and parameter values of the DC-link capacitor are indicative of a predicted temperature of the capacitor being greater than a threshold to maintain capacitor temperature lower than the threshold. The parameter values are obtainable from a thermal model of the DC-link capacitor. The thermal model may be derived from testing a test version of the PEM under different drive cycles in which for each drive cycle a set of information is recorded including a sensed temperature of the inverter power switch test version, a current of the PEM test version, and a sensed temperature of the DC-link capacitor test version.