Study Of Self-powered Circuit Breaker Based On Normally-on SiC JFET

With the rapid development of power electronic devices,a new type of circuit breaker based on power electronics,the Solid-state Circuit Breaker(SSCB),was born in the last century.Compared with the traditional mechanical circuit breakers,solid-state circuit breakers Due to its advantages of small size,high speed,no arc generation when it is turned on or off,it has been rapidly developed in the field of medium and low voltage transmission.The power electronic devices based on Si material semiconductors have great restrictions due to their large switching losses,low withstand voltage levels,and low junction temperatures.The third-generation power electronic devices represented by Si C materials have the advantages of low on-state resistance,fast switching speed,and high thermal conductivity,which provide a broad space for the development of solid state circuit breakers.This article describes a self-powered solid state circuit breaker using a Normally-on Si C Junction Field-Effect Transistor(JFET)and a DC/DC isolation transformer with a circuit breaker directly in series.The circuit breaker detects the short-circuit fault by detecting the drain-source voltage of the JFET.After a short-circuit fault occurs,the drain-source voltage of the JFET is converted to the JFET's drive voltage by the DC/DC isolation transformer to turn off the JFET,thereby shutting down the short-circuit current.Unlike previous solid state circuit breakers,the operation of a self-powered solid state circuit breaker does not require the provision of an external auxiliary power source.In order to verify the reliability of the self-powered solid state circuit breaker,the circuit of each module of the self-powered circuit breaker was designed.Experimental prototypes were made and corresponding experiments were conducted.The experimental results show that the fabricated prototype basically meets the requirements of circuit breaker shutdown short-circuit fault,and has achieved the experimental expected results.