Research on topology optimization of high-voltage DC circuit breaker based on controllable capacitor oscillation

HVDC circuit breakers are the core equipment for the reliable operation of VSC-HVDC. The controllable resonant DC circuit breaker amplifies the oscillating current through excitation capacitor oscillation and boost, quickly generating a current zero point, and achieving the transmission of fault current and circuit breaking. In this paper, controlled resonant DC circuit breaker with a half-bridge topology structure is first simulated. But this topology structure cannot generate a current crossing point when the oscillation frequency decreases, resulting in the mechanical switch cannot be broken. So, a DC circuit breaker with a full-bridge topology structure is proposed, and the simulation results show that the topology structure can make the oscillation current rises quickly. Compared with the half-bridge topology circuit, its current crossing zero point can be created when the oscillation frequency reduces. Finally, in order to verify the safety and reliability of the full-bridge topology, stress analysis is conducted on the full control device and diodes, which provides a basis for the safe and reliable operation and electrical structure design of the high-voltage DC circuit breaker.