Study of reliability-efficiency tradeoff of active thermal control for power electronic systems

Active thermal control for power modules can potentially extend the lifetime of the converter. This paper investigates the trade-off between the lifetime extension or de-rating and its cost due to the efficiency reduction. A short review on the existing approaches using control to reduce thermal stress of power modules is presented. Based on a given junction temperature profile, a method to evaluate the active thermal control's trade-off is presented. The concept is validated on a laboratory setup, where active thermal control is implemented by adapting the switching frequency. A discussion of the possible lifetime extension at the efficiency's expense is finally given.