Power Modules for Pulsed Power Applications Using Phase Change Material

The current requirement of a pulsed load may be many times of the average value. To prevent over temperature, short-term over current capability is needed. The over current capability of existing power modules is barely a few microseconds, which is mainly constrained by the junction temperature. This study customizes a power module with enhanced short-term current capability using phase change material (PCM). Thanks to the great thermal capacity of PCM during melting, the power module can support pulsed load three times the rated value for tens of seconds with appropriate PCM. To avoid unacceptably increasing thermal resistance, a metal framework is utilized. Two different 3D printed metal frameworks are presented and compared. Device power losses in a grid-connected inverter is calculated, followed by the thermal model for this case study. Simulation is conducted to show the effects of PCM thickness and proportion concerning the phase change time, dynamic thermal response and steady state thermal resistance, followed by the optimization of design using finite element analyses (FEA). Finally, the effect of the PCM is verified through experiment. When the junction temperature of the device is controlled below the limit, the power module can indeed handle the required large current for an intended duration.