Condition Monitoring Technique of Power Electronic Modules via Square-Wave Gate Signal Modulation

Abstract:
As demonstrated in previous work, an efficient way to detect and localize various degradation modes in power modules is to excite periodic losses via sinusoidal gate-source voltage vGS modulation. This allows extracting the phase shift between vGS and the resulting drain-source voltage vDS as an indicator of the thermal path’s state of health, as it changes with degradation at characteristic bandwidths. This paper demonstrates that the excitation does not have to be sinusoidal, but can also be a square wave, allowing an easier hardware implementation. It thus simplifies the integration of the diagnostic circuitry into the gate driver. Moreover, fewer frequencies need to be excited individually, since a square wave excites the odd harmonics, that can be evaluated for degradation detection as well. Thus, measuring time can be reduced.