Thermal Impedance Spectroscopy by Varying the Gate Voltage during Inverter Operation

Abstract:
A low-frequency sinusoidal superposition on the positive gate voltage in the on-state of power semiconductors causes a temperature fluctuation which can be measured by the internal gate resistance based junction temperature monitor during inverter operation. This paper describes the necessary components of the circuit and presents measurement results. This measuring principle allows the detection of thermal impedance changes during inverter operation without the need for special load profiles.