Abstract: The volume and cost of the transformer coupling bridge-type solid-state fault current limiter（ SSFCL） depend on the components of the fault current limiter including the series coupling transformer, rectifier bridge and current-limiting inductance. To reduce the volume and cost of the coupling transformer, a novel auto-transformer coupling bridge-type SSFCL is proposed with a detailed analysis of its working principle and current-limiting process. For the problem of large current-limiting inductance due to the inability of rectifier bridge thyristor to control the turn-off, the topology of the secondary side of SSFCL is improved by using fullcontrolled power electronic devices. The improved topology has the ability to shorten the time for the bridge and current-limiting inductance to withstand the inrush current while reducing the amplitude and the slope of inrush current. Thus, the related parameters of power electronic devices in rectifier bridge and current-limiting inductance can be decreased and the cost of SSFCL further cut.Simulation results show that SSFCLs with auto-transformer are more efficient and cost-effective than those with normal transformer with the same current-limiting objective. The effectiveness of the improved SSFCL is validated by experiment.