A Practical Partial Chip Failure Detection Method for Half-Bridge Structures

Monitoring partial chip failures in multi-chip IGBT modules is crucial for enhancing the reliability of high-power converters. This paper proposes a partial chip failures diagnosis method based on the IGBT equivalent turn-off time. Partial chip failures result in a significant increase in the current in the remaining functional chip. And the IGBT equivalent turn-off time exhibits high sensitivity on current variation under low-current operating conditions. Therefore, the IGBT equivalent turn-off time under small current conditions can serve as an effective indicator for partial chip failure detection. The feasibility of the proposed approach is fully validated by semiconductor theory analysis and double-pulse test experiment. Furthermore, a low-cost, high-accuracy detection circuit suitable for half-bridge structure is designed in this paper to extract this time. With the support of this circuit, the proposed method shows great promise for practical engineering applications.