SENSITIVITY ANALYSIS METHOD OF TEMPERATURE-DEPENDENT PARAMETERS DURING TURN-ON PROCESS OF SIC POWER MOSFETS

Elevated temperature and thermal cycling are one of the biggest limiting factors in the service lifetime of power modules in power electronic systems. Thus, accurate and high-bandwidth junction temperature measurement of power semiconductors is essential for condition monitoring as well as for remaining useful life estimation procedures. The extraction of temperature sensitive electrical parameters (TSEP) has been identified as a promising approach for junction temperature sensing. However, TSEPs are usually affected not only by temperature but also by other effects, such as load current and aging effects. In addition, the overall temperature sensitivity of the TSEP is influenced by several individual sensitivities of separate device parameters. A strong understanding of these impacts is crucial for highly accurate temperature determination. However, sensitivity analysis of TSEPs to these influences is rarely performed in the literature. Therefore, this paper introduces a sensitivity analysis method of turn-on process TSEPs derived from fitting a simulation model to measurement results through a genetic algorithm. To verify the method, the sensitivity of SiC power MOSFET turn-on TSEPs to threshold voltage, internal gate resistance and transconduction gain are extracted and evaluated.