Research on Active Thermal Control: Actual Status and Future Trends

The trend toward integrating power electronic converters and pushing their device utilization toward physical limits puts the spotlight on the junction temperature of the devices. The physical limits of power density are directly tied to the maximum junction temperature and junction temperature cycles that are considered as the root cause of the aging and, finally, the failure of the device. Therefore, manipulating the junction temperature with smart control algorithms is a promising method to enhance the power density and the lifetime of future converter systems. To address these opportunities, recent research proposed methods that increase the overload capability, reduce thermal cycles, balance thermal stress, and share thermal loading of power converters. This article systematically analyzes the fundamental principle and the key objective of these methods and discusses their limitations and potential. Based on this discussion, it highlights important challenges, such as thermal state variable extraction, nonlinear aging, and minimizing the impact on system operation. These challenges must be addressed by future research to make active thermal control a key enabler of a smart power converter with superior power density and reliability.