A Novel Method for Online Junction Temperature Monitoring of Power Module Based on In-Situ Sensor Fabrication

Online monitoring of junction temperature (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$T_{j}$</tex-math></inline-formula>) in power modules is crucial for enhancing the performance and reliability of systems. However, existing methods for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$T_{j}$</tex-math></inline-formula> monitoring face several challenges, including device aging, lack of universality, and intrusive damage. To solve these difficulties, this study innovatively proposes a monitoring method based on the in-situ fabrication of temperature sensors. Sensors are directly fabricated between the chip and the upper copper layer of the direct bond copper board. This approach can apply to various chips demonstrating exceptional universality. It eliminates the need to open the case, with data transmission achieved through bonding wires. After that, the proposed method requires a low sampling rate and narrow range, thus allowing for cost-effective online monitoring. Furthermore, the article establishes a temperature differential model (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Delta T$</tex-math></inline-formula>) caused by the difference between the sensor's actual in situ and theoretical locations. Through experimental validation, the sensor's steady-state characteristics, transient response, and effectiveness in online monitoring are confirmed. The results affirm that in-situ fabricated sensors achieve great performance in online <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$T_{j}$</tex-math></inline-formula> monitoring.