A Temperature-Dependent Analytical Transient Model of SiC MOSFET in Half-Bridge Circuits

In this article, a temperature-dependent transient model of silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (<sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small>) is proposed. The switching transient of the SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> is divided into four phases. In each phase, the operations of the <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> and its body diode are analyzed and the corresponding equivalent circuits are obtained. The analysis identifies that the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$C_{gd}\times dV_{ds}/dt$</tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$L_{s}\times dI_{d}/dt$</tex-math></inline-formula> induced negative feedback mechanisms, excess charge extraction in the N-base of SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> body diode and dynamic transfer characteristics at switching transient are pivotal physical characteristics. The dependence 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">$T_{J1}$</tex-math></inline-formula> of low-side <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> and 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">$T_{J2}$</tex-math></inline-formula> of high-side <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> on the switching behavior of SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> is also analyzed and included in the proposed model. Based on the improved understanding of the switching behavior, an analytical model of SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> is derived. The analytically derived switching waveforms and switching losses are compared to the test data and good agreement is obtained.