Influence And Optimization Of Stray Inductance On SiC MOSFET Switching Process

Compared with traditional silicon(Si)materials,silicon carbide(SiC)materials have obvious advantages in terms of band gap width,thermal conductivity,melting point and breakdown field strength.Similarly,SiC power semiconductor devices have greater advantages in high voltage,high temperature,and high frequency compared to conventional silicon(Si)based power devices,so SiC power devices are more and more widely used,and in SiC power semiconductors devices,the development of SiC MOSFETs is the most mature and widely used.SiC MOSFETs have lower on-resistance and switching losses,higher switching frequency,and better high-temperature stability than comparable Si MOSFETs or Si IGBTs.Although the performance of SiC MOSFETs is better than that of traditional Si-based devices of the same voltage class,due to the small stray capacitance of the chip,the switching speed is very fast,which will cause the SiC MOSFET to withstand the switching process under the action of stray inductance.Large electrical stresses can cause damage or failure of the device in severe cases.Therefore,in order to make full use of the excellent performance of SiC MOSFET,it is necessary to analyze the influence of stray inductance on the switching characteristics of SiC MOSFET and optimize the stray inductance accordingly.This paper relies on the National Key Research and Development Project "High Voltage High Power SiC Materials,Devices and Its Application in Power Electronic Transformer" of Ministry of Science and Technology.The influence of stray inductance on the switching process of SiC MOSFETs is analyzed,and its optimization scheme is given.In this paper,the SiC MOSFET switching transient characteristic test system is designed and built firstly,and the extraction method of SiC MOSFET package inductance and commutation loop stray inductance is proposed to provide the basis for the measurement of stray inductance optimization.Then the effects of package inductance and commutation loop stray inductance on the transient characteristics of SiC MOSFET switching are analyzed by simulation and experiment.The optimization scheme of package inductance and stray inductance of converter loop is proposed.