A hybrid circuit breaker comprised of a high-speed mechanical switch and power semiconductor devices has advantages such as a large discharge capacity, a fast turn-off speed, and a strong current-limiting capability, and thus has become a hot issue to study in the field of breaking a large capacity system. Compared with other hybrid solutions, a hybrid DC circuit breaker scheme that uses a power semiconductor device with a full control function to break current has advantages such as a faster breaking speed and greater facilitation of breaking rational current. However, when breaking current using the full-control type power semiconductor device, its current transfer loop usually requires the full-control type power semiconductor device to switch off the current, consequently increasing complexity and cost, which restricts its promotion and application.
In a traditional transfer current circuit, a capacitor charging circuit is directly connected to a main loop. Without isolation, interference will occur to a charging power source and the main loop during a breaking process. Moreover, it is highly demanding on voltage-withstanding capability of the main loop charging power supply, and the breaking is not reliable.