Research On Low Voltage DC Circuit Breaker Based On New Silicon Carbide Silicon

The role of low-voltage DC circuit breaker(LVDC breaker,low voltage direct current breaker)is in the low-voltage direct current circuit failure,overload or abnormal operation to disconnect the circuit.In recent years,with the continuous development of science and technology,DC power distribution can bring higher power quality,making the application of DC more extensive,and DC circuit breaker is to support the low-voltage DC circuit breaker is mainly used in low-voltage direct current distribution network,DC distribution network safe and stable operation of the key parts,so DC circuit breaker has been a hot research in recent years.In recent years,the performance of DC circuit breakers has been approaching the limits of Si materials,to develop a better performance circuit brea kers need to use new semiconductor materials,silicon carbide materials in recent years with the continuous maturity of its low conductivity Pass loss,high temperature,high frequency and breaking speed advantages.Compared to Si-MOSFETs and IGBTs,silicon carbide MOSFETs are particularly suitable for use as switching devices in DC circuit breakers.The main work of this thesis is to study the feasibility of silicon carbide MOSFET with breakdown voltage of 1.2KV for 500 V DC circuit breaker,and try to prototype the prototype.Secondly,the working principle and advantages and disadvantages of the three main DC circuit breakers are introduced.Then,the material properties,the DC voltage level,the insulation of the circuit breakers,and the characteristics of the silicon carbide MOSFETs are introduced.And the electrical safety and other aspects to determine the working voltage of circuit breakers designed in this paper 500V;Then the SiC-MOSFET turn-on and turn-off process of the circuit characteristics,and Saber software SiC-MOSFET modeling specific process;Then the simple low-voltage DC circuit model is built and the parameters of each component in the model are estimated.Then the overvoltage of the SiC-MOSFET in normal operation and failure is analyzed.On the basis,two overvoltages Circuit protection circuit to ensure the safe and reliable work of SiC-MOSFET;Finally,the circuit breaker in the main circuit,over-voltage protection circuit,current detection circuit,control circuit and drive circuit five parts of the design,and then complete prototype prototype circuit diagram.This thesis designed the circuit breaker breaking capacity is small,larger,through continuous improvement and improvement is expected to achieve the circuit breaker in real life applications.