Self-triggered low-voltage hybrid DC circuit breakers have the advantages of low loss

high performance

and selective protection. Facing the new requirements for 1 500 V and above breaking in low-voltage DC systems

it is still necessary to solve the design challenges of large capacity and miniaturization

low cost and high reliability. A series arc asynchronous coordination topology is proposed

where breaking units A and B are formed by the series connection of multiple poles in a molded case circuit breaker (MCCB)

with an electronic module connected in parallel with unit B. The arc in unit B drives natural current commutation

while unit A maintains continuous arcing to reduce the current rise rate during IGBT conduction and increase the total breaking voltage during metal oxide varistor (MOV) operation. Upon completion of the breaking process

the arc extinction in unit A ensures reliable electrical isolation. By cooperatively distributing high voltage stress between the arc in unit A and the electronic module

the breaking voltage rating increases from 750 V to 1 000 and 1 500 V without modifying existing MCCB or electronic module designs

while the interruption time is reduced to ~11 ms. Regarding the decrease in arc voltage and its rise rate of unit B in this topology

its influence on energy extraction

current commutation

and arc reignition is explored. The study reveals that the charging time of the energy supply circuit is prolonged and a unique platform period appears; the current commutation time is approximately unchanged

and the device power loss is greatly reduced; the arc reignition probability increases

which can be mitigated through proper MOV selection and timing sequence control. The research results provide important theoretical and method references for the development of new high performance low-voltage hybrid DC circuit breakers.