Theoretical Study on the Generation of Switching Stress Waves in Power Semiconductor Devices

Appropriate condition monitoring methods can evaluate the status of power semiconductor devices in time. The traditional methods of condition monitoring are based primarily on the identification of electrical, magnetic, and thermal parameters. In recent years, studies have found that power semiconductor devices can generate stress waves when they are turned on and off, which can be detected by acoustic emission sensors. Acoustic emission detection technology has the characteristics of rapidity, noninvasiveness, and real-time performance. It is a supplement to conventional condition monitoring methods and is anticipated to be used for the online monitoring of power semiconductor devices. However, the source mechanism of the stress waves that power semiconductor devices produce when they turn on and off has not yet been identified, which is not conducive to the further application of acoustic emission detection technology in power semiconductor devices. Therefore, taking an insulated-gate bipolar transistor as an example, this article proposes new theoretical models to explain the reason for the stress wave generated by the device at the time of turn-off, and verifies the rationality of the models through formula derivations, finite-element simulations, and experimental results.