Abstract: A method of controlling a modular multilevel converter, MMC, of a full-bridge or mixed arm type in case of a DC line disturbance is provided. The method includes determining whether a magnitude of a DC voltage (Udp) of the MMC has fallen below an upper voltage threshold (Ud_max_lim), and, if determining that the magnitude of the DC voltage has fallen below the upper voltage threshold, reducing both a magnitude of an AC active current reference (IVD_ORD) and a magnitude of a DC voltage reference (UDC_REF) for the MMC based on the DC pole voltage. An MMC with a controller implementing the method, a converter station including at least one such MMC, and a power transfer system including at least one such converter station, are also provided.

Abstract: A method of controlling a modular multilevel converter, MMC, of a full-bridge or mixed arm type in case of a DC line disturbance is provided. The method includes determining whether a magnitude of a DC voltage (Udp) of the MMC has fallen below an upper voltage threshold (Ud_max_lim), and, if determining that the magnitude of the DC voltage has fallen below the upper voltage threshold, reducing both a magnitude of an AC active current reference (IVD_ORD) and a magnitude of a DC voltage reference (UDC_REF) for the MMC based on the DC pole voltage. An MMC with a controller implementing the method, a converter station including at least one such MMC, and a power transfer system including at least one such converter station, are also provided.

Abstract: A first voltage source converter and converter station including such a first voltage source converter, as well as a method and computer program product for controlling the first voltage source converter are disclosed. The first voltage source converter has a DC side for connection to a DC system, has an AC side for connection to an AC system and is interconnected with an AC side of a second voltage source converter, which has a DC side connected to the DC system. The first voltage source converter includes a number of converter valve pairs, each being connected to a corresponding AC phase of the AC system and a control unit controlling the converter valves to generate at least one AC waveform and to reduce oscillations between the converters.

Abstract: A first voltage source converter and converter station including such a first voltage source converter, as well as a method and computer program product for controlling the first voltage source converter are disclosed. The first voltage source converter has a DC side for connection to a DC system, has an AC side for connection to an AC system and is interconnected with an AC side of a second voltage source converter, which has a DC side connected to the DC system. The first voltage source converter includes a number of converter valve pairs, each being connected to a corresponding AC phase of the AC system and a control unit controlling the converter valves to generate at least one AC waveform and to reduce oscillations between the converters.