Investigation of the Effect of Bonding Wires Degradation on Switching Stress Waves Released During Power Cycling in Discrete IGBT

Effective condition monitoring (CM) technology ensures the safe operation of insulated gate bipolar transistors (IGBTs). Most CM methods for IGBTs focus on extracting electrical, thermal, and magnetic parameters. Recent studies indicate that at the switching moment, IGBTs can emit the switching stress wave (SSW) that is detectable by the acoustic emission (AE) sensors. However, using these SSWs to monitor the health status of IGBTs, even for discrete devices with relatively simple package structures, remains challenging. This article investigates how SSWs from discrete IGBTs during power cycling change as bonding wires degrade and whether these waves are promising for monitoring the condition of internal bonding wires. In this work, a power cycle test platform and an SSW test platform for discrete IGBTs are built, and SSWs from discrete IGBTs during power cycling are analyzed. Results show that SSWs vary with the degradation of the device's bonding wires, with changes in the time domain indicator of signal energy, reflecting SSW strength, and the frequency domain indicator of the center of gravity (COG) frequency, reflecting frequency shifts. These findings suggest the possibility for developing AE-based detection technology (AEDT) in CM of the IGBT.