A Novel Discrete Branch Bidirectional Solid-State Circuit Breaker based on Mixture Device

Solid state circuit breakers(SSCBs)based on fullcontrolled devices such as IGBT and based on half-controlled devices such as thyristor have their respective advantages.The mixture device solid state circuit breaker(M-SSCB)combines the advantages together and can achieve lower loss,high efficiency,active and reliable blocking at the same time.However,the conduction loss will increase significantly when the topology expanding to a bidirectional topology because the bidirectional line commutation switch(LCS)structure composed of two groups of IGBTs in reverse series.In this paper,a novel discrete branch mixture SSCB(DBM-SSCB)is proposed,bidirectional current only flows through one IGBT that has the obvious conduction losses advantage at the same voltage and current level.Only one energy-absorbing component is shared by two discrete branches can guarantee optimal costs and volume.By calculation,the proposed DBM-SSCB can reduce the conduction loss about 30.4%in 10 k V MVDC system,while retaining other advantages of the mixture device SSCB,such as without introducing additional thyristors,charging power supply and the ability to actively interrupt bidirectional fault currents.The blocking principles and designing guidelines are presented in detail,the feasibility is verified by 500 V-18 A simulation results and scale-down experiment,the engineering calculation and simulation of 10 k V-1 k A prototype is completed and compared with other DCCBs.Experimental results and comparative analysis show that the proposed DBM-SSCB has both lower losses and significant performance advantages thus has a good engineering application prospect.