Power module stray inductance extraction: Theoretical and experimental analysis

Abstract

AbstractWe 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.

Keywords

• double‐pulse tester
• power module
• stray inductance
• turn‐off switching