Online monitoring method for degradation of insulated gate bipolar transistor

Abstract

The invention discloses an online monitoring method for degradation of an insulated gate bipolar transistor (IGBT). The online monitoring method can be used for monitoring the degradation degree of the IGBT in actual operating process, so as to send out early warning before the IGBT fails. The online monitoring method comprises the steps of: under the condition that the IGBT does not degrade, conducting a temperature experiment on an IGBT to be monitored, measuring junction temperature indexes (invariant voltage drop) representing IGBT junction temperature levels at different junction temperatures of the IGBT to be monitored and degradation indexes (conductive resistance) representing IGBT degradation degrees, and calculating a proportionality coefficient of degradation index variable quantity and junction temperature index variable quantity under the same junction temperature variation; and under the condition that the IGBT degrades, measuring a junction temperature index and a degradation index online, carrying out optimization of removing junction temperature influence on the degradation index by combining with the proportionality coefficient obtained through the temperature experiment under the normal condition, and monitoring the degradation degree of the IGBT to be monitored according to the optimized degradation index.

Description

technical field [0001] The invention belongs to the technical field of reliability engineering and relates to an on-line monitoring method for degradation of an insulated gate bipolar transistor. Background technique [0002] Insulated Gate Bipolar Transistor (IGBT) is composed of Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) and Bipolar Junction Transistor (Bipolar Junction Transistor, BJT for short) is a full-controlled voltage-controlled power switching device, which has the advantages of voltage control, high input impedance, fast switching speed, small on-resistance, and large current capacity, so it is widely used in power transformers such as inverters. In the converter, it is the main body to realize the power conversion. [0003] In practical applications, the IGBT is in a repeated on-off state, so the junction temperature of the IGBT also rises and falls alternately. This operation process is called the power cycle process of the IGBT. Due to the dif...

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Problems solved by technology

Due to the difference in the coefficient of thermal expansion (Coefficient of Thermal Expansion, CTE) of each component material that makes up the IGBT package structure, the contact surface between the various component materials of the IGBT is subjected to repeated mechanical stresses due to repeated changes in temperature during the power cycle. stress, thereby continuously degrading, resulting in aluminum metal layer reconstruction and bond wire fracture failure

[0004] At present, in the existing methods for monitoring IGBT degradation, its degradation index has many limitations, such as it cannot be measured online, or it is affected by the change of load current, or it is affected by the change of junction temperature.

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