The insulated gate bipolar transistor (IGBT), one of the most vulnerable component, is one of the most precious central component in the converter interior. High junction temperature will lead to device failure, which is the main reason of failure of power electronic system. Therefore, on-line high precision measurement of IGBT module junction temperature is the basis of life prediction and reliability evaluation of high-power power conversion equipment. In this paper, the principle of IGBT junction temperature extraction and the latest development of related technologies are summarized. In particular, the working principle and shortcomings of temperature sensitive electrical parameter (TSEP) method are summarized. The change of junction temperature will affect the inter-electrode capacitance in the internal structure of IGBT, which will cause the change of temperature sensitive electrical parameters. The single temperature sensitive electrical parameter method is easily affected by IGBT structure and inter-electrode capacitance. This paper presents an algorithm for high precision on-line detection of IGBT junction temperature. The parameter types are optimized by stepwise regression and the model is established accordingly. In this paper, IGBT: FF50R12RT4 is used as the experimental equipment. By comparing the junction temperature model established based on multiple linear stepwise regression algorithm with the junction temperature model based on traditional temperature sensitive electrical parameters, it is proved that the algorithm has better fitting degree and precision, and the algorithm can be used for high precision online extraction of junction temperature.

Temperature-sensitive electrical parameter (TSEP) approaches are widely employed in the junction temperature (T _j ) extraction and prediction of power semiconductor devices. In this paper, the turn-off loss (E _off ) and turn-off time (t _off ) are presented as temperature-sensitive electrical parameters. The abrupt change in the junction temperature of Insulated Gate Bipolar Transistor (IGBT) occurs during switching is proved. Common deficiencies in a single temperature-sensitive electrical parameter were considered, including the necessity of the collector currents exaction, the poor junction detection accuracy. Therefore, after the linear relationship between junction temperature and turn-off time, and turn-off loss is proved, a hybrid model based on turn-off loss (E _off ) and turn-off time (t _off ) is proposed to extract junction temperature accurately. The experimental results show that the proposed method is with the advantages of high accuracy and strong anti-interference ability. Although some high-precision probes are required for parameter extraction, it indicates the internal mechanism of junction temperature mutation of the power device, and it is of great value for the reliability of the power devices that operate continuously.

Temperature sensitive electrical parameter (TSEP) approaches are widely employed in the junction temperature ( $T_{j}$ ) detection and prediction of power devices, especially the switching parameter. In this article, the voltage-rise time and its loss during the turn-off process are used as the TSEP index for the detection of junction temperature because of the coupling relationship with the maximum junction temperature. In addition, the effect of junction temperature on the current-fall time and its loss is compared. The theoretical analysis is verified by SABER simulation and H-bridge inverter circuit platform. It is established that the model based on voltage-rise time ( $t_{\mathrm {rv}}$ ) and voltage-rise loss ( $E_{\mathrm {rv}}$ ) is a viable model with good linearity, fixed sensitivity, and offers nondestructive insulated gate bipolar translator (IGBT) junction temperature extraction.

Accurate online junction temperature detection of high-power Insulated Gate Bipolar Transistor (IGBT) modules is necessary for the health management system of key equipment. The voltage rise time (t _rv ) is a good temperature sensitive electrical parameter (TSEP), which is of great significance for its accurate online extraction. In this manuscript, a novel IGBT junction temperature detection based on the high-frequency (HF) model of inductor element is proposed. Firstly, the equivalent model of the inductor element in the application circuit at high frequency is demonstrated. Secondly, based on the HF model of the inductor element, it is proposed and verified that the t _rv in the IGBT turn-off process is consistent with the high frequency current pulse signal on the inductor element at HF, that is, the t _rv can be indirectly obtained by extracting the high frequency current pulse signal. Finally, the feasibility for voltage rise time extraction and junction temperature detection through high-frequency isolation coil is verified by experiments and simulations. The research work in this manuscript is helpful to the on-line junction temperature detection, and has certain theoretical significance and practical engineering value.

In this paper, a temperature sensitive electrical parameter (TSEP) method for insulated gate bipolar transistor (IGBT) modules junction temperature estimation based on voltage integral over-voltage rise period (VIVRP) is proposed. Firstly, combined with the principles of thermodynamic physics, the movement characteristics of internal carriers and holes are discussed, and the waveform of voltage and current during the turn-off process is studied. The feasibility of using voltage integral overvoltage period instead of voltage rise loss in junction temperature measurement is discussed and proved. At the beginning of the turn-off process, the holes in the IGBT almost remain in spatial and temporal distribution (the collector current IC remains constant), which leads the VIVRP to a cheaper TSEP method for junction temperature detection, without the high-frequency current detection equipment. Finally, the junction temperature model based on VIVRP and the extraction circuit of VIVRP are proposed. In addition, it is compared with the junction temperature detection method based on the voltage rise time and voltage rise loss. The results show that the junction temperature detection method based on VIVRP proposed in this paper is detection with high precision and low cost.

The multi-chip parallel insulated gate bipolar transistor (IGBT) is the core device in large-capacity power electronic equipment, but its operational reliability is of considerable concern to industry. The application of IGBT online degradation state analysis technology can be beneficial to the improvement of system reliability. The failure mechanism of IGBT devices is discussed in this paper, and a technique for analyzing the degradation state of IGBT based on apparent junction temperature is proposed. First, the distortion consistency of the voltage rise time in various failures is discussed, and the junction temperature dependence of the voltage rise time is then demonstrated. Subsequently, an apparent junction temperature model based on the voltage rise time is established (the fitting accuracy is as high as 94.3%). From the high-frequency model in the switching process of the device, an online extraction technology of key parameters (e.g., voltage rise time) is developed. Finally, an experimental platform for IGBT degradation state estimation is established, and the feasibility of IGBT degradation state estimation based on apparent junction temperature is proved, especially the degradation of bonding-wire and the gate-oxide-layer. The experimental results show that the proposed IGBT degradation state estimation technique based on apparent junction temperature is a reliable online estimation method with non-contact, high accuracy, and comprehensiveness.