CONVERTER AND CONTROL METHOD OF SAME

摘要

A converter and a control method of same. The converter comprises at least one phase unit. Each phase unit comprises an upper bridge arm (100) and a lower bridge arm (110), the upper bridge arm and the lower bridge arm both comprise at least two sub-modules (10, 11) connected in series to each other and at least one electric reactor (20), all sub-modules in the same bridge arm are connected in the same direction, and the connection direction of the sub-modules in the upper bridge arm is contrary to that of the sub-modules in the lower bridge arm; one ends of the upper bridge arm and the lower bridge arm are respectively used as a first and a second direct current endpoints (P, N) of the phase unit, which are used to access a direct current network; and the other ends of the upper bridge arm and the lower bridge arm are short-circuited to each other and used as an alternating current endpoint (A) of the phase unit, which are used to access an alternating current network. The sub-module comprises three disconnectable devices (1, 3, 5) having antiparallel diodes (2, 4, 6), one diode (7), and one energy storage element (8). When the converter is shut down due to a direct current fault, an alternating current system can be prevented from injecting the faulty current to the direct current network; in this way, the temporary fault of the direct current network is eliminated without the need of tripping an alternating current incoming breaker, thereby accelerating the reboot of the system.