Evaluation method for IGBT off-state current trailing degradation

Abstract

The invention relates to an evaluation method for IGBT off-state current trailing degradation. The method comprises the steps that off-state current time sequence data of multiple sets of IGBTs to be tested are collected in real time; filtering the off-state current time sequence data of the IGBT to be detected to obtain off-state current time sequence trend data; a double-index model U = a * exp (b * k) + c * exp (d * k) is constructed, model parameters of the double-index model are obtained through calculation according to off-state current time sequence trend data, a, b, c and d represent the model parameters of the double-index model, and k represents a cycle period; according to the model parameters, establishing a state equation U (k) used for fitting an off-state current degradation track of the IGBT, and evaluating off-state current degradation of the to-be-tested IGBT according to the state equation U (k); wherein the state equation U (k) is U (k) = a * exp (b * k) + c * exp (d * k), in the formula, U represents a trend singular point value, and k represents a cycle period. According to the method for evaluating the off-state current trailing degradation of the IGBT, the accurate trajectory of parameter degradation is extracted through singularity analysis, meanwhile, the calculation precision is guaranteed, and the estimation speed of the off-state current of the IGBT is increased.

Description

technical field [0001] The invention belongs to the technical field of IGBT devices, and in particular relates to an evaluation method for IGBT off-state current trailing degradation. Background technique [0002] IGBT devices are usually used in high-power switching states, and the application characteristics involve multi-disciplinary interdisciplinary such as thermals, electricity, mechanics, and materials. Its reliability research and optimal design are of great significance to the development of power module failure theory and its industrialization. In-depth research on IGBT power modules It comprehensively analyzes the influence of chip characteristics, packaging materials, process, structure and other factors on module reliability, and proposes reliability protection and evaluation technology, which has significant engineering application value. [0003] IGBTs usually work under high temperature, high voltage, and high current environmental conditions. Due to the larg...

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Problems solved by technology

[0004] Although IGBT development units at home and abroad usually adopt the safety protection domain design of temperature and electrical stress, the frequent failure of IGBT devices still leads to failure of power electronic equipment and even the whole machine. Therefore, an effective real-time detection and evaluation of IGBT working performance is needed. method, a large number of field data show that with the improvement of semiconductor technology and power electronic system optimization design technology, the current IGBT performance degradation mainly manifests in the off-state current degradation, that is, the current of the IGBT in the off-state should quickly decrease to a small value, but In practice, it needs to go through a slow state before entering the off state, which leads to a section of the IGBT that will withstand the impact of high voltage and high current. As this switching state continues, the existence of this high-power section is The continued degradation of the device off-state provides the physical driving force

[0005] At present, the accuracy of detection and degradation evaluation methods for IGBT off-state current tailing characteristics is poor, and it is impossible to make an accurate evaluation of IGBT degradation performance.

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