IGBT condition monitoring with system identification methods

This work investigates the aging effects of the degraded effective heat dissipation path of power semiconductor devices. Solder layer fatigue is identified as one of the commonly observed wear-out failures that reduces the system availability and reliability. A health monitoring method is proposed with system identification techniques, which allows for the early detection of the presence of abnormal thermal behaviors and evaluation of solder layer health. The thermal network is built for thermal characterization and it can be updated online with system identification technique. This can ensure the junction temperature being accurately estimated under the condition of degraded heat dissipation path. A fast and low computational burden estimation method is preferred for online implementation and the Fast Affine Projection algorithm is used. Compared with conventional adaptive algorithm, such as Least Mean Squares and Recursive Least Squares methods, it has fast convergence speed and low computational burden. The simulation result shows its superior performance to the alternative techniques.