The dc power system, due to its convenience of conversion, integration, and use, is getting immense attention in the field of power transmission and distribution. It is superior to the traditional ac systems in terms of efficiency, reliability, and control simplicity as well. A dc circuit breaker is one of the important elements of any dc power system. It is a sophisticated technology designed to break dc current only. The breaking of a dc current is always challenging compared with the breaking of an ac current, as dc current does not have natural zero crossing points like ac current has. Moreover, dc current breaking becomes more critical when the current is inductive as energy stored in the network inductance opposes instantaneous current breaking. Hence, this energy needs to be absorbed and dissipated as heat during the current breaking operation, which is exactly what is done in the traditional dc circuit breaker topologies. This article introduces a new topology for dc circuit breakers with a mechanism to reuse this stored energy instead of dissipating it. The mechanism is analogous to regenerative braking in electric drive systems and can enhance the overall system efficiency. The proposed scheme was analyzed through rigorous computer simulation and was experimentally validated.

The direct current circuit breaker (DCCB) is extensively employed in DC microgrid applications to protect the network during faults. However, numerous DC converters are combined in parallel to form a DC microgrid, which creates a large network inductance. The grid stores energy during regular operation, which repels instantaneous current breaking, and this stored energy needs to be eliminated after current breaking. Conventional topologies use different energy absorption methods to dissipate the stored energy after breaking the current. In this paper, an efficient bidirectional DC circuit breaker (EBDCCB) topology is introduced to extract and reuse this energy instead of dissipating it. The proposed topology has bidirectional power flow capability to meet the requirements of DC microgrid applications as energy storage devices are frequently utilized. Furthermore, EBDCCB shows drastically improved performance in terms of current breaking time, voltage stress, regenerated average current, and energy recovery efficiency compared to the conventional DCCB topology. The mathematical modeling and sizing of the components used in the proposed EBDCCB are elaborately analyzed, and detailed performance testing is presented along with extensive PSIM software simulation. Additionally, an experimental investigation is conducted on a laboratory-scale 48 V/1 A prototype.