Abb Technology Ag

Abb Technology Ltd

Abb Schweiz Ag

Arman Hassanpoor

Jürgen Häfner

A method and computer program product are provided for selecting switching cells for voltage contribution in a phase arm of a multilevel converter, a cell selecting control device for a multilevel converter and a multilevel converter. The cell selecting control device and multilevel converter includes a balancing control element that obtains a reference voltage for the phase arm, obtains a measurement of the current running through the phase arm and selects cells for contributing to an AC voltage output from the multilevel converter based on the reference voltage and the magnitude of the phase arm current.

Multilevel converter with cells being selected based on phase arm current

A high voltage direct current (HVDC) hybrid circuit breaker is provided. The circuit breaker includes a solid-state main breaker, a mechanical fast disconnector and a solid-state auxiliary breaker connected in series, the series-connection of the disconnector and the auxiliary breaker being connected in parallel to the main breaker, a snubber circuit including a capacitor, and a switching device being arranged for disconnecting the snubber capacitor in response to the auxiliary breaker being opened. By disconnecting the snubber capacitor, an uncontrolled discharging of the capacitor through the disconnector and the main breaker, and the resulting non-zero current flowing through the disconnector during the breaking action, may be avoided. Further, a method of an HVDC hybrid circuit breaker is provided.

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Ludvika, Sweden

Arman Hassanpoor