On-line temperature estimation of SiC power MOSFET modules through on-state resistance mapping

Abstract

The paper deals with real-time estimation of the junction temperature of a SiC power MOSFET modules. The junction temperature of one device of the module is real-time estimated by measuring its current and on-state voltage at each time sample, and entering the temperature model of the device. The temperature model is obtained in a dedicated commissioning session, where the v ON is measured at different temperature and current conditions. A sequence of current pulses of short duration is closed-loop imposed to the device at different values of the measured DBC substrate temperature, so that the temperature measurement is consistently representing the junction temperature during the identification. The presented results show that the proposed method permits on-line temperature monitoring and even closed loop regulation of the junction temperature of the tested SiC power MOSFET modules. Different module from two different manufacturers are tested under realistic operating conditions. This concept can be usefully applied to all DC/AC conversion structures, where the monitoring of one device can be of reference value for the entire module.