Spatial Thermal Frequency Response Measurement of Power Semiconductor Equipment

This paper presents spatial thermal frequency response analysis and measurement as a tool enabling the design of power electronic modules and converter systems for maximal density. It starts with model-based synthesis of a scaling law describing how geometric dimensioning and material selection shapes stressful thermal transients induced by device losses. Next, the paper presents a key evolution to state-of-the-art system identification methods for characterizing transient heat transfer. A proposed measurement setup utilizes infrared thermography to capture spatial temperature gradients resulting from forced, transient semiconductor device loss dissipation. Measurement results are presented in the time domain and, after synthesis, in a compact frequency domain format. Coherent frequency response function measurements quantify the amplitude attenuation and phase delay induced by detailed spatial domain effects, such as component interfacing. Close inspection of results reveal measurement synchronization requirements and how the methodology can be exploited to profile surface topology in prototype assemblies.