Power module stray inductance extraction: Theoretical and experimental analysis

• Published in: ETRI journal 2021-10, Vol.43 (5), p.891-899
• Main Authors: Jung, Dong Yun, Jang, Hyun Gyu, Cho, Doohyung, Kwon, Sungkyu, Won, Jong Il, Lee, Seong Hyun, Park, Kun Sik, Lim, Jong-Won, Bae, Joung Hwan, Choi, Yun Hwa
• Format: Article
• Language: Korean
• ISSN: 1225-6463; 2233-7326

We propose a stray inductance extraction method on power modules of the few-kilovolts/several-hundred-amperes class using only low voltages and low currents. The method incorporates a double-pulse generator, a level shifter, a switching device, and a load inductor. The conventional approach generally requires a high voltage of more than half the power module's rated voltage and a high current of around half the rated current. In contrast, the proposed method requires a low voltage and low current environment regardless of the power module's rated voltage because the module is measured in a turn-off state. Both theoretical and experimental results are provided. A physical circuit board was fabricated, and the method was applied to three commercial power modules with EconoDUAL3 cases. The obtained stray inductance values differed from the manufacturer-provided values by less than 1.65 nH, thus demonstrating the method's accuracy. The greatest advantage of the proposed approach is that high voltages or high currents are not required.