Research of Self-Excited Short Circuit Method for Monitoring IGBT Health Status With Improved Temperature Criterion

The bonding wires and busbars in IGBT modules may have open points and breaks during long-term use, causing changes in short-circuit current. The health status of the IGBT module can be analyzed by detecting and judging the short-circuit current. The self-excited short circuit monitoring technology controls the gate voltage to cause small current short circuits in the IGBT. By detecting the magnitude of the self-excited short circuit current, the damage to the IGBT module bonding wire is determined. The accuracy of the monitoring results of this method is affected by changes in device junction temperature. Based on the application scenario of urban rail traction inverters, this article proposes an improved temperature criterion for the self-excited short-circuit monitoring method. The multidimensional relationship between IGBT module short circuit current, health level, and temperature changes is analyzed. The temperature ranges for self-excited short circuit detection based on the actual operating conditions of urban rail inverter is studied, and the driving module status judgment is set to only determine the health status of effective data points within the temperature range. This method can suppress the influence of IGBT working temperature on short-circuit condition detection and improve the accuracy of the criterion. At last, a current detection experiment was conducted to simulate the fracture of bonding wires, verifying the effectiveness of the proposed method.