System and method for estimating junction temperatures of a power semiconductor module

摘要

A system for estimating junction temperatures of a power semiconductor module comprises a constant current source configured to apply a constant drain current to a drain terminal of a power semiconductor device of the power semiconductor module, an adjustable gate voltage source configured to provide a gate voltage signal to a To apply the gate terminal of the power semiconductor device, a drain-source voltage sensor coupled between the drain terminal and the source terminal, wherein the drain-source voltage sensor is configured to measure a value of the current drain-source voltage across the To measure power semiconductor device and output a corresponding drain-source voltage signal, a gate controller which is configured to determine a difference between the drain-source voltage signal and a constant reference voltage and the output of the adjustable gate voltage source as a function of the determined difference, and a system controller which is configured to switch the power semiconductor device into its fully conductive state if the deviations in the gate-source voltage over time remain within a tolerance band, and the junction temperature in the power semiconductor device as a function from the on-resistance of the power semiconductor device in the fully conductive state.