VSC Converter Feedback Control Data Optimization Based IGBT Collector Emitter Saturation Voltage Monitoring Through Nonlinear Least Squares Method

Power switching device insulated gate bipolar transistor (IGBT) is a key component in the power conversion system (PCS). Fatigue-induced aging of its electrical characteristics can lead to serious degradation of PCS, such as increased losses and temperatures, fault shutdowns or equipment damage, even safety risks for the battery units. The collector-emitter saturation voltage Vce is an essential indicator of IGBT health status, and the monitoring this on-state saturation voltage can effectively assess its operational health. However, data-driven modeling-based monitoring algorithms are highly dependent on data quality and scale, and substandard data quality can cause significant deviations in the data model, besides extra sensors may not be feasible to be implemented on existing converters. To tackle these challenges, this paper introduces a PCS feedback control data based nonlinear least squares curve fitting algorithm for the precise identification of the saturation voltage of IGBT. The PCS model has been established, which incorporate the IGBT dead-time switching character to enhance the accuracy. Additionally, for the collected feedback control data, a Kalman filter observer is constructed to reduce data deviations and noise interference, successfully mitigating the impact of sampling noise on identification accuracy. Finally, the correctness and effectiveness of the proposed IGBT on-state saturations voltage monitoring method are verified through Matlab/Simulink simulations and experimental setup.