Methodology for Active Thermal Cycle Reduction of Power Electronic Modules

04/12/2018

Christoph H. van der Broeck, Lukas A. Ruppert, Robert D. Lorenz, Rik W. De Doncker; IEEE Transactions on Power Electronics, 2018

 

This paper proposes a methodology for active thermal control for power electronic modules in AC applications that includes a loss manipulation unit, a thermal observer structure and an active thermal cycle reduction algorithm. It aims to reduce the thermo-mechanical strain in the interconnects of the module in order to enhance its reliability and lifetime. The loss manipulation unit is realized least invasively by manipulating adaptive gate resistances and the pulse-width-modulation frequency. This allows the individual thermal control of multiple devices within a power module that has not been achieved in prior work. A thermal observer structure is introduced that estimates averaged device temperatures by combination of a thermal model and sensor information. The observer technology makes this work the first to realize closed-loop control of averaged temperatures achieving an increased robustness and insensitivity to modeling errors. A key element of the active thermal cycle reduction algorithm is a virtual heat sink that derives feasible and stress releasing thermal trajectories. The trajectories are applied with a unique thermal feedback structure that smoothly manipulates the averaged junction temperature of the power module even in the presence of loss manipulation limits. The active thermal control methodology is evaluated experimentally with a state-of-the-art IGBT power module.

Link: IEEE Xplore