Alstom Technology Limited

General Electric Technology Gmbh

Michael Marc Claude Merlin

Timothy Charles Green

David Reginald Trainer

Omar Fadhel Jasim

Nnamdi Okaeme

Kevin J Dyke

Colin Donald Murray Oates

William Crookes

Francisco Jose Moreno Muñoz

Masoud Bazargan

Sajjad Fekriasl

Ralph Feldman

Diego Soto-Sanchez

In the field of high voltage direct current power transmission networks, a method of controlling a converter that includes at least one converter limb which corresponds to a respective phase of the converter, is described. The method includes obtaining a respective AC current demand phase waveform for each converter limb which the corresponding converter limb is required to track, and a DC current demand which each converter limb is also required to track. The method further determining a limb portion current for each limb portion that the limb portion must contribute to track the corresponding required AC current demand phase waveform and the required DC current demand, and providing a limb portion voltage source for each limb portion to achieve the corresponding limb portion current. The method carrying out mathematical optimization to determine one or more optimal limb portion currents and/or provide optimal limb portion voltage sources.

Converter and method of controlling a converter

An alternate arm converter includes at least one converter limb that defines first and second limb portions. Each limb portion includes at least one director switch connected in series with a chain-link converter between one of two DC terminals and an AC terminal of the converter. The chain-link converters are operable to generate a voltage waveform at the AC terminal, and the director switches are operable to switch the respective chain-link converters in and out of circuit between the respective DC terminal and the AC terminal. The converter also includes a controller configured to selectively control the switching of each director switch to form a current circulation path including each limb portion and the DC network. The controller, during formation of the current circulation path, forces an alternating current to flow through the current circulation path to transfer energy between the chain-link converters of the limb portions.

Alternate arm converter

A power electronic converter for use in high voltage direct current power transmission and reactive power compensation comprises three converter limbs, each converter limb including first and second DC terminals for connection in use to a DC network and an AC terminal for connection in use to a respective phase of a three-phase AC network, each converter limb defining first and second limb portions being connected in series between the respective AC terminal and a respective one of the first and second DC terminals, each limb portion including at least one switching element being controllable in use to facilitate power conversion between the AC and DC networks, the power electronic converter further including a plurality of auxiliary units, each auxiliary unit being operably associated with the respective phase of the AC network, each auxiliary unit including at least one module including a voltage source, the limb portions being controllable in use to define at least one three-phase static synchronous compensator including at least one of the plurality of auxiliary units in each branch of a star configuration, each of the first and/or second DC terminals defining the neutral point of the respective star configuration.

HVDC converter including fullbridge cells for handling a DC side short circuit

A power electronic converter for use in high voltage direct current power transmission and reactive power compensation includes at least one converter limb, which includes first and second DC terminals and an AC terminal. Each converter limb defines first and second limb portions connected in series between the AC terminal and a respective one of the first and second DC terminals. Each limb portion includes a chain-link converter connected in series with at least one primary switching element. Each chain-link converter includes a plurality of modules connected in series, and each module includes at least one secondary switching element connected to at least one energy storage device. Each primary switching element 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 in a respective chain-link converter.

Modular multilevel power electronic converter having selectively definable circulation path

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Dourdan, France

Michael Marc Claude Merlin