Research On Silicon Carbide MOSFET Behavior Model And EMC In Motor Drive System

Motor drive systems are widely used in weapons and equipment,rail transportation,new energy vehicles,industrial production and other fields,and power switching devices are the core of the motor drive system.As the efficiency and energy consumption of the motor drive system have been drawn more and more attention,SiC(silicon carbide)devices with excellent characteristics such as high switching speed,high rated voltage and good heat dissipation have also attracted researchers’ attention.Recently,fully commercialized silicon carbide MOSFET is considered as a substitute for traditional IGBT devices.However,due to the faster switching speeds of silicon carbide MOSFETs,EMI problems in motor drive systems are more severe than with traditional IGBT systems.Therefore,research on SiC MOSFET performance and SiC MOSFET motor drive system EMI has become a hot topic in academia.In this dissertation,some of research is done on the related fields of silicon carbide motor drive system.It is considered that the characteristics of silicon carbide devices are the root causes of the problem of electromagnetic compatibility of silicon carbide motor drive system relative to the traditional motor drive system.Therefore,the focus of this dissertation is on the switching behavior of silicon carbide MOSFETs and the direct relationship between the switching behavior and the EMI of the motor drive system.In order to study the switching behavior of the device and the factors that affect the switching behavior of the devices,this dissertation presents a behavioral model of silicon carbide MOSFET based on a dual-pulse test loop.By analyzing the states of the silicon carbide MOSFETs in the circuit topology the relationship between the silicon carbide MOSFET switching process is divided into four stages,The behavioral model proposed in this dissertation including the model of the nonlinearity parasitic capacitance of the MOSFET and the relationship between channel current and gate source voltage and the interaction between the power loop and the gate loop in a two-pulse SiC MOSFET test circuit.the model proposed in this dissertation can well reflect the behavior of SiC MOSFET in the switching process.The impact of EMI in the entire drive system is another focus of this dissertation.the relationship between switching behavior of SiC MOSFET and motor drive system EMI has been researched.At the same time,the spectrum of EMI in the motor drive system was studied and quantified by using Fourier transform.Finally,a set of SiC MOSFET motor drive system is designed.