Electrical-Thermal Coupling Modeling of SiC MOSFETs Based on Field-Circuit Coupling and Its Application in Junction Temperature Calculation During Surges

Chip temperature is crucial for assessing the surge reliability of silicon carbide metal-oxide-semiconductor-field-effect transistors (SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small>s). Unlike conventional reliance on virtual junction temperature in normal conditions, evaluating the non-uniform temperature distribution across the chip under surge conditions is essential for robustness and field reliability. This paper proposes a novel field-circuit coupling model for temperature calculation of SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small>s. The proposed field-circuit coupling model enables the collaborative computation of temperature fields and circuits within circuit simulation platforms, capturing the spatial distribution of electrical and thermal properties across the chip. The validity of the field-circuit coupling calculation model is verified through three different test conditions. The electrical and thermal characteristics of SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small>s under different surge current amplitudes are analyzed, leading to a prediction of the maximum surge current capacity of the device. The method proposed in this paper extends the traditional field-circuit coupling method, providing a novel perspective for calculating the temperature of power devices under extreme conditions. To enhance understanding, this paper is accompanied by a video demonstrating the computational process of the proposed method.