Abstract: The requirement for the high-speed and large-capacity DC circuit breaker（DCCB） hampers the development and application of the modular multi-level converter high voltage direct current（MMC-HVDC） grid. The current-limiting schemes based on hybrid MMC are restricted by the particular topology, and thus are not suitable for existing systems based on half-bridge MMC. This paper proposed an emergency current-limiting control scheme with generality of submodule topologies and fault types, which can reduce the breaking current and absorbed energy of the DCCB. The principle of the emergency current-limiting control, together with its coordination strategy with DCCB, were firstly introduced. The calculating equations of fault currents under current-limiting control were derived. The influence of the different switching time on the development of the fault current was studied. Eventually, the four-terminal DC grid based on half-bridge MMC was simulated. The simulation results show that the proposed current-limiting control can not only reduce breaking current and absorbed energy of the DCCB by 4.29 kA（40.74%） and 23.4 MJ（60.47%）, respectively, but also can be suitable for high-resistance fault.