Improved Short-Circuit Protection Method for SiC MOSFET Split-Output Power Module Achieving Ultra-Low Fault Dissipated Energy
Hongyi Gao, Hai Dong, Yuting Jin, Fujun Zheng, Ankang Zhu, Haoze Luo, Wuhua Li, Xiangning He
Abstract
Due to ultrafast switching speed and high-frequency switching 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> s), crosstalk effect, high turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> losses and electromagnetic interference are becoming constraints to the efficient and safe applications of SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s. The split-output structure has attracted widespread attention due to its advantages of overcoming the above constraints by integrating decoupling inductors. Thereby, it fully exploits the potential benefits of SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s. In this article, the effects of the split inductors on short-circuit characteristics of split-output power module are analyzed. An analytical model of the split-output power module is established to compare the electrical characteristics of the split inductors under normal operation and short-circuit faults. A dedicated short-circuit protection method is proposed based on the detection of the voltage pulse duration across the split inductors. The protection method is validated by hard switching fault and fault under load experiments. The results show that the short-circuit power device can be shut down when the short-circuit current is much lower than the continuous drain current. Besides, the short-circuit energy of the power device has the same order of magnitude as the dissipated energy under normal switching, which avoids degradation and even destruction of SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s under short-circuit faults.