IGBT Condition Monitoring Drive Circuit Based on Self-Excited Short-Circuit Current

The electrical parameters of the insulated gate bipolar transistor (IGBT) module change over the service life. By detecting the values of these parameters, the aging state of the IGBT module can be identified. Bond wire damage is the main characteristic of IGBT module degradation, and the impedance change of bond wire can directly affect the IGBT short-circuit current. In this article, an IGBT condition monitoring drive circuit based on a self-excited short-circuit current is designed. The drive circuit is directly connected to the IGBT module, which can obtain IGBT data from the lowest level and determine the aging state of IGBT most quickly. First, the relationship between IGBT short-circuit current and aging state is analyzed. Through the model establishment and mathematical calculation, it is concluded that the short-circuit current decreases after bond wire damage. Second, the self-excited short-circuit condition is introduced. By setting the gate voltage and collector-emitter voltage, IGBT condition monitoring can be realized with a small short-circuit current. Considering the influence of junction temperature on short-circuit current, a junction temperature monitoring circuit is designed to ensure that the temperature is basically consistent during condition monitoring. Finally, the IGBT bond wire damage experiment is carried out by using the IGBT condition monitoring drive circuit, which verifies the feasibility of the proposed method.