An Improved IGBT Short-Circuit Protection Method With Self-Adaptive Blanking Circuit Based on V CE Measurement

IGBT short-circuit protection is the key factor to improve the reliability of the power electronics system. The conventional short-circuit protection method based on VCEmeasurement detects the collector-emitter voltage of an IGBT to determine whether the IGBT short-circuit fault occurs. The blanking circuit is needed in this kind of protection method to avoid the false triggering of the short-circuit protection during IGBT turn-on transient. However, this blanking circuit should be carefully designed for different types of IGBT modules. In order to make the IGBT short-circuit protection circuit suitable for the tolerance of IGBT modules, a self-adaptive blanking circuit combined with the aforementioned short-circuit protection method based on VCEmeasurement is proposed. The proposed method is achieved by feeding back the required minimum blanking time interval which is decided by comparing the desaturation reference voltage with the collector-emitter voltage. The short-circuit protection delay time for the conventional circuit and the proposed circuit are compared. Experimental results are included to prove the effectiveness of the proposed circuit.