An Accurate Datasheet-Driven Analytical Model of SiC MOSFET Incorporating Stage-Dominant <i> C <sub>gs</sub> </i> ( <i> V <sub>gs</sub> </i> , <i> V <sub>d</sub> <sub>s</sub> </i> ) and <i> C <sub>gd</sub> </i> ( <i> V <sub>gs</sub> </i> , <i> V <sub>d</sub> <sub>s</sub> </i> )
Xin Yang, Xiaodi Wang, Qing Li, Yanchao Liu, Yifei Sun, Guoyou Liu
Abstract
SiC MOSFET analytical models demonstrate higher computational efficiency and simpler implementation than physical/behavioral models. However, existing analytical models fail to properly account for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V<sub>gs</sub></i>-dependent <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C<sub>gs</sub></i>/<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C<sub>gd</sub></i> dynamics, causing significant errors in switching waveform predictions and switching characteristic parameters (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">di<sub>ds</sub></i>/<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dt</i>, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dv<sub>ds</sub></i>/<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dt</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t<sub>delay</sub></i>). Current SiC MOSFET analytical models implement <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C<sub>gs</sub></i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C<sub>gd</sub></i> characterization through either lookup tables or parameterized mathematical expressions, where certain parameters require additional experimental data. This paper presents an accurate analytical model for SiC MOSFETs. This model provides physics-based expressions for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C<sub>gs</sub></i>(<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V<sub>gs</sub></i>,<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V<sub>ds</sub></i>) and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C<sub>gd</sub></i>(<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V<sub>gs</sub></i>,<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V<sub>ds</sub></i>), derived from charge-potential theory and simplified to capture the dominant capacitance dynamics in each switching Stage. Parameter extraction is performed exclusively using datasheet information. Experimental verification shows <10% loss prediction error, compared with 15-45% in existing analytical models. The model's universality has been validated using C3M0016120D, enabling converter optimization, dead-time control and snubber design.