Online Detection of IGBT Voltage Rise Time Based on <i>RC</i> Circuit Current

The study shows that junction temperature significantly affects the performance of Insulated Gate Bipolar Transistors (IGBTs), and the junction temperature of an IGBT can be accurately assessed through its voltage rise time. This parameter is crucial for evaluating the health status of both the IGBT and the entire inverter system. To enable low-intrusiveness detection of IGBTs during inverter operation, a new method is proposed in this paper: a parallel RC high-frequency detection circuit at the inverter output terminal to monitor the IGBT’s voltage rise time. This method not only accurately identifies and measures the voltage rise time of IGBTs in a three-phase inverter, but also accounts for practical operating conditions. Simulations and experimental validation are carried out for different operating conditions, load connection methods, cable lengths, and uncertainties in parasitic parameters, and the experimental results verify the effectiveness as well as the strong robustness of the method.