A Double-Sided Bidirectional Power Module With Low Heat Concentration and Low Thermomechanical Stress

Abstract

Double-sided structure leads to severe thermal mismatch, making attachments easy to fail. For the double-sided bidirectional switch (BDS) module, the heat concentration in the buffering spacers further increases the risk of thermal fatigue failure of the attachment, which is the key difficulty that limits the reliability and the application of the double-sided BDS module. This letter proposed a reliable double-sided BDS module with the bridge buffering spacers for both improving the heat dissipation and reducing the thermomechanical stresses. Simulation results showed that the bridge buffering spacer can decrease T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">jmax</sub> and the maximum thermomechanical stress of the attachment between the IGBT-1 and the spacer by ~9% and ~35%, respectively. Furthermore, it was proved by the power cycling tests that the lifetime of the double-side BDS module using the bridge buffering spacer can be at least two times longer, i.e., more than 200 k cycles, than the one using the traditional brick buffering spacer under the same load and ~21% longer under the same T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">jmax</sub> and ΔT <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">j</sub> .