A Failure Diagnosis Method for Multichip IGBT Modules Using a Novel Chip Failure Sensitive Parameter

Multichip insulated gate bipolar transistor (mIGBT) modules are widely used in high‐power converters, yet their reliability is often threatened by chip open‐circuit failures caused by bond wire lift‐off. Therefore, achieving early health condition assessment of mIGBT modules is of great significance. This paper proposes a diagnosis method for chip failures in mIGBT modules based on chip failure sensitive parameter (CFSP). The principle of this method is to extract the overshoot voltage V ge(os) from the gate loop and the overshoot voltage V eE(os) from the Kelvin emitter branch to obtain CFSP. Firstly, an equivalent circuit model of mIGBT modules is established to support the theoretical analysis, which reveals that CFSP decreases as the number of active chips reduces. Then, a double‐pulse test (DPT) platform is built for experimental validation, and results indicate that the sensitivity of CFSP increases with the severity of chip failure in the mIGBT module, although it exhibits strong immunity to variations in operating conditions. Furthermore, the proposed method is unaffected by the external gate resistance and eliminates the need for complex sensitivity calibration, thereby simplifying the chip failure monitoring process.