Inverter IGBT Degradation Diagnosis Case : Failure precursor-based early detection

Latent Damage Accumulation in IGBTs and Post-Failure Detection

As a core component of the inverter, the IGBT accumulates latent internal damage when repeatedly exposed to electrostatic discharge (ESD). The primary challenge is that this damage remains invisible from the outside, making it impossible to verify the progression of degradation through conventional inspections. Because the root cause could only be identified after a failure occurred, the company faced recurring issues that required total inverter replacement or costly production line shutdowns.

Development of a Precursor Model:
Quantifying Degradation Patterns for Pre-Failure Anomaly Detection

By analyzing the degradation mechanisms of IGBTs, we successfully derived "precursors"—early indicators that exhibit measurable changes prior to actual failure. We developed a predictive model to quantitatively track the progression of degradation based on variation patterns in key parameters, such as threshold voltage and switching times. These insights were subsequently integrated into optimizing inverter designs.

Realization of an Early Inverter Fault Detection and Design Optimization Framework

The precursor-based model enables the quantitative assessment of degradation levels before the internal damage of the IGBT reaches a critical threshold, establishing a continuous, data-driven component health monitoring system that moves away from conventional reliance on visual inspections. By shifting from a reactive approach—where failure causes were traced only after the fact—this framework proactively maps the degradation path driven by cumulative ESD exposure, allowing for preemptive intervention the moment anomalies are detected to significantly reduce unexpected production line downtime. Furthermore, the insights derived from this degradation model have been integrated directly back into the inverter design process, refining design standards to extend IGBT lifespan even under identical ESD environments and establishing a strong foundation for enhancing both component reliability and overall operational stability.