IGBT Junction Temperature Monitoring Method Current Calibration Free Based on the Narrow Pulse Injection

Insulated gate bipolar transistor (IGBT) junction temperature monitoring is crucial for IGBT reliability assessment and health management. However, most traditional methods are involved with calibrating current, which increases the complexity of the practical application. In this article, an IGBT junction temperature monitoring method current calibration free based on the narrow pulse injection is proposed. A narrow pulse is injected in the expected current, which allows temperature monitoring at a fixed current value, thus avoiding the current calibration. Besides, the voltage overshoot of the narrow pulse has a linear relationship with IGBT junction temperature. The dependence of narrow pulse voltage overshoot on junction temperature is analyzed in detail. The setup of narrow pulse injection is introduced. The experiments are conducted, and the feasibility of the proposed method is verified. Moreover, considering a typical permanent magnet synchronous motor as the load, the effect of a narrow pulse on load is analyzed. The analysis results indicate that the influence of narrow pulse injection is tiny for a motor load. The IGBT junction temperature monitoring method based on the narrow pulse injection has the advantages of no current calibration and high monitoring resolution and flexibility.