Article,
A Sparsity-Promoting Time Domain Evaluation Method for Thermal Transient Measurement of Power Semiconductors
Affiliations
- [1] Aalborg University [NORA names: AAU Aalborg University; University; Denmark; Europe, EU; Nordic; OECD];
- [2] RWTH Aachen University [NORA names: Germany; Europe, EU; OECD]
Abstract
This article investigates evaluation methods of thermal transient measurements to obtain the internal thermal structure of semiconductor devices. First, the study uncovers the limitations of a widely accepted standard method that uses frequency-domain deconvolution. An important finding is that the sideband of the time constant spectrum by the standard method has no physical meaning despite it beeing interpreted as a continuous spectrum for a long time. Second, by understanding the limitations of the existing method, the article proposes an alternative method that remodels the frequency-domain deconvolution as a regularized least squares problem in the time domain. With the benchmark of the true values of several thermal networks based on simulation, the proposed sparsity-promoting method demonstrates several advantages, including a better ability to identify adjacent parameters in the time-constant spectrum and the obtained structure function reducing relative error by an order of magnitude. The influence of varying noise levels has also been evaluated. Finally, a proof-of-concept experiment using a commercial power semiconductor device validates its effectiveness.