Research And Design Of Gate Drive Circuit For High Voltage Silicon Carbide MOSFET

With the further development of modern power electronics technology,aerospace,orbital traction,wireless power transmission and new energy vehicles and other fields have put forward higher requirements for the physical properties of power device material substrates.There are more and more applications of high voltage and high current,and traditional silicon substrate materials are subject to their own physical characteristics,which cannot meet the requirements of high efficiency,low loss and the use of devices in some specific engineering occasions.A new generation of wide bandgap semiconductor materials such as SiC and Ga N have gradually emerged in the semiconductor market because of their advantages of high switching frequency,low switching loss and high power density,attracting the research enthusiasm of power electronics workers.SiC MOSFETs have attracted much attention in high-frequency and high-voltage applications due to their good physical properties under high temperature and high voltage conditions.The design of the drive circuit is an indispensable part of the application process of the device,and the advantages and disadvantages of the entire drive circuit design directly affect the work efficiency,stability and safety of the power electronic equipment,so the research and design of the drive circuit of the device is very necessary.At present,the domestic research on SiC MOSFET drive circuit is still in its infancy compared with foreign countries,and the drive circuit design under high voltage is more scarce,on this basis,this thesis proposes a high voltage drive circuit,and the main work is as follows:Firstly,the internal structure of SiC MOSFET is analyzed,the internal parasitic parameters of the device are discussed,and the equivalent model is established,and the static operating characteristics of the device are introduced in detail.Establish a dynamic test platform to test the dynamic characteristics of the device in combination with the switching process of the device,and deeply understand the operating characteristics of the device at high-speed switching frequency,so as to provide a reference for the subsequent drive circuit design.Secondly,the drive technology of SiC MOSFET is introduced,the consideration of voltage resistance and other parameters of the drive circuit is analyzed,and the overall architecture of the drive circuit is studied in combination with the drive signal control module,the drive power isolation module and the drive protection module,which provides a theoretical basis for the proposal of high-voltage drive circuit in the following chapters.Finally,using the flyback converter topology,a drive power supply with high galvanic isolation level is designed,and the model simulation of transformer is carried out by using the Maxwell module in the finite element analysis software Ansys,and a signal control module based on optical fiber isolation is proposed.Finally,a SiC MOSFET driver circuit that can be applied to high-voltage environment is designed,and a hardware test platform is built to verify the performance of the designed driver circuit.