Contact pressure monitoring of press-pack IGBT using ultrasonic reflection coefficient method

Abstract

In this paper, a contact pressure online monitoring method of PP-IGBT based on the ultrasonic measurement is proposed. A finite element (FE) model of PP-IGBT is established. The dynamic contact pressure within PP-IGBT during power cycling process is analyzed based on the FE model. An ultrasonic measuring system for contact pressure measurement of PP-IGBT considering the structure of the device and fixture is designed. A temperature compensation method using coupling interface reflection wave is proposed to eliminate the influence of temperature on measuring the contact pressure. A power cycling test platform is established to verify the effectiveness of the proposed method. Results show that the proposed method can realize the non-invasive online measurement of the contact pressure in PP-IGBT.