MODULAR MULTILEVEL CONVERTER

摘要

A power electronic converter (30) for use in high voltage direct current power transmission and reactive power compensation comprises at least one converter limb (32). The or each converter limb (32) includes first and second DC terminals (34,36) for connection in use to a DC network (40) and an AC terminal (38) for connection in use to an AC network (42). The or each converter limb (32) defines first and second limb portions (44,46) which are connected in series between the AC terminal (38) and a respective one of the first and second DC terminals (34,36). Each limb portion (44,46) includes a chain-link converter (50) which is connected in series with at least one primary switching element (48). Each chain-link converter (50) includes a plurality of modules (52) which are connected in series, and each module includes at least one secondary switching element (54) that is connected to at least one energy storage device (56). The or each primary switching element (48) in each limb portion of a respective converter limb selectively defines a circulation path which carries a DC circulation current to regulate the energy level of at least one energy storage device (56) in a respective chain-link converter (50).