Thermal Parameter Monitoring of IGBT Module Using Junction Temperature Cooling Curves

In this paper, we propose a method to monitor the thermal parameters of insulated gate bipolar transistor (IGBT) module using the junction temperature cooling curves. Relationship between the time constants of junction temperature cooling curves and thermal parameters of the Cauer model is established for condition monitoring. Advantages of the proposed approach include no need to measure the power loss and to heat the module to thermal equilibrium. Simulation and experimental tests are performed to verify the accuracy and effectiveness of the proposed method. Results show that the proposed method can not only monitor the thermal parameter of a single layer, but also enable the concurrent monitoring of thermal parameters in multiple layers.

I. Introduction

Power converters that use insulated gate bipolar transistors (IGBTs) have been widely used in various applications, such as ac drive motion control, uninterruptible power system (UPS), renewables (wind and solar), etc. [1]. According to an industry-based survey presented in [2], the IGBT module is rated as one of the weakest components in the converter. Consequently, it is urgent that the reliability of IGBT module can be enhanced and condition monitoring has been proved to be a cost effective means [3].