PHM method for detecting degradation of GaN HEMT ON resistance, application to power converter

Abstract

Due to the superior physical properties of Wide bandgap (WBG) based power switching devices, silicon carbide (SiC) and gallium nitride (GaN) are believed to be promising candidates to replace Silicon in power electronics converters for EV/HEV applications. That is for this reason that the reliability of these switching devices is an important parameter which conditions their insertion in industrial applications. It is in this context that the subject of this paper falls, aiming at studying the reliability of these new generations of transistors by implementing an in-situ monitoring system in a 48 V/12 V DC/DC converter in order to monitor the evolution of the Rdson. Therefore, we propose a study focusing in the monitoring of Rdson considered as one of more important degradation indicator of a GaN transistor. After an introduction presenting the context of the study, the principle of PHM is described in this paper. The GaN transistor and its use in DC/DC converters are described. The method for monitoring Rdson, a sensitive parameter of the transistor, is developed. The simulations highlight the interest of such a monitoring method to predict the ageing of the transistor, while emphasising the practical difficulties of implementation.

Keywords

• GaN transistor
• Power converters
• Prognostics
• Health management
• Online monitoring