Research On SiC MOSFET Crosstalk And High Frequency Oscillation Suppression

Power devices are an important part of power electronics technology and have a pivotal position in industrial applications and transmission and distribution.While putting higher demands on industrial automation,there is no room for further improvement in the application of silicon-based power devices in frequency converters,but the emergence of silicon carbide materials has broken this technical bottleneck.Scholars at home and abroad have expressed that SiC MOSFET will replace IGBT and become the mainstream of the new generation of power devices.This thesis studies the following:First,it describes the development of power devices and the engineering and academic background of SiC MOSFET.It summarizes the domestic and foreign research status of SiC MOSFET in application.Secondly,the power MOSFET and the relevant characteristics of SiC MOSFET are preliminarily introduced.The switching behavior model of SiC MOSFET is introduced emphatically.For different stages of power device turn-on and turn-off process,an equivalent circuit is drawn and a mathematical equation is established.Then,the problem and suppression method of SiC MOSFET bridge crosstalk are proposed.Through the combination of theoretical analysis and simulation experiments,the principle of crosstalk is explained.Various design methods for driving circuits to suppress crosstalk are introduced,and this thesis uses an improved gate drive circuit based on the active crosstalk suppression method.The working principle of the new driving circuit is analyzed,and design parameters are given.The simulation software and experimental platform are introduced to provide analysis methods and experimental support for drive circuit.The validity of this drive circuit is verified by a double-pulse test experiment.Finally,a new resonant damping circuit is proposed to reduce the oscillation phenomenon during switching.The parasitic parameters are introduced,and the phenomena of turn-on oscillation and turn-off oscillation of SiC MOSFET are studied.The oscillation frequency and damping coefficient are quantitatively analyzed theoretically,and specific calculation formulas are given in different stages.A resonance damping circuit composed of a hollow PCB is proposed to suppress the switching oscillation of the SiC MOSFET.At the same time,the experiment verifies that the driving circuit can suppress the voltage and current oscillation of the power side under different conditions.There are 56 pictures,4 tables and 83 references in this thesis.