Abstract: There is provided a switching valve for a voltage source converter, the switching valve including a number of modules, each module including at least one switching element and at least one energy storage device, each switching element and each energy storage device arranged to be combinable to selectively provide a voltage source, the switching valve including a controller programmed to selectively control the switching of the switching elements to select zero, one or more of the modules to contribute a or a respective voltage to a switching valve voltage. The controller is programmed to selectively control the switching of the switching elements to carry out a switching operation and to apply a time delay if a charging current is flowing through the modules and/or apply a time delay to a start time of the switching operation if a discharging current is flowing through the modules.

Abstract: A method of determining submodule capacitor degradation. The method includes determining voltage change of at least one submodule capacitor during a control cycle whilst the at least one submodule is switched into a valve circuit and assigning the voltage change dVvsm. The method further includes determining average voltage change across all in-circuit submodules during the control cycle and assigning the average voltage change as dVaverage. The method further includes determining relative capacitance of all in-circuit submodules by comparing dVvsm to the dVaverage. The method further includes determining capacitance deviation of all in-circuit submodules to quantify how much the capacitance deviates from the average voltage change dVaverage. The method further includes comparing the determined capacitance deviation against a pre-defined threshold value to identify degraded in-circuit submodules.

Abstract: There is provided a method, and a controller, for controlling a number of submodules in a valve of a power converter, the method including: determining, by a controller, a first switching time for a first submodule of the submodules; determining, by the controller, a second switching time for a second submodule of the submodules, wherein the first switching time differs from the second switching time by a time difference; wherein the time difference is based on a property of resonance in the power converter, wherein the resonance in the power converter is that caused by switching at least one submodule of the submodules in the valve; and providing, by the controller, one or more switching commands to the valve to cause the first submodule to switch at the first switching time and the second submodule to switch at the second switching time.

Abstract: There is provided a method, and a controller, for controlling a number of submodules in a valve of a power electronics device. The method includes determining, by the controller, a time period in which selected submodules of the submodules are to be switched in order to control an output voltage of the valve; determining, by the controller, for each of the selected submodules, a respective switching time, within the time period, based on a voltage demand for the time period and a voltage of each of the selected submodules, wherein at least one of the respective switching times is different to another of the respective switching times; generating, by the controller, a respective switching command for each of the selected submodules; and providing, by the controller, the respective switching commands to the valve, whereby to control the selected submodules to switch at the respective switching times within the time period.

Abstract: There is provided a switching valve for a voltage source converter, the switching valve including a number of modules, each module including at least one switching element and at least one energy storage device, each switching element and each energy storage device arranged to be combinable to selectively provide a voltage source, the switching valve including a controller programmed to selectively control the switching of the switching elements to select zero, one or more of the modules to contribute a or a respective voltage to a switching valve voltage. The controller is programmed to selectively control the switching of the switching elements to carry out a switching operation and to apply a time delay if a charging current is flowing through the modules and/or apply a time delay to a start time of the switching operation if a discharging current is flowing through the modules.

Abstract: There is provided a switching valve for a voltage source converter.

Abstract: There is provided a switching valve for a voltage source converter.