Abstract: An inverter arrangement based on photovoltaic elements includes at least two strings including switching elements, which strings are connected to at least two AC terminals, where at least one of the strings is a string of submodules, each submodule including at least two switching elements and an energy storage element, having DC terminals and being configured to make a voltage contribution to the forming of an AC voltage on an AC terminal, and a number of input stages each including at least one energy delivery element, where at least some of the energy delivery elements are photovoltaic elements, each input stage being connected to DC terminals of a corresponding for delivering power to or from at least one AC terminal when the corresponding submodule contributes to the forming of the AC voltage on the AC terminal.

Abstract: A multilevel converter converting between AC and DC includes a phase leg having a first and a second phase arm, the first phase arm being connected between a first pole having a first potential and a first AC terminal and the second phase arm being connected between the first AC terminal and a second potential, where the phase arms include half-bridge and full-bridge cells, where each cell includes at least one energy storage element for providing the voltage contribution and cell switching units with cell switches and anti-parallel diodes for controlling the voltage contribution, where the full-bridge cells include a bypass switch controllable to bypass the corresponding energy storage element, and when a phase-to-ground fault occurs the cell switches are blocked and the bypass switches activated with a delay in relation to the blocking.

Abstract: A multilevel converter converting between AC and DC includes a phase leg having a first and a second phase arm, the first phase arm being connected between a first pole having a first potential and a first AC terminal and the second phase arm being connected between the first AC terminal and a second potential, where the phase arms include half-bridge and full-bridge cells, where each cell includes at least one energy storage element for providing the voltage contribution and cell switching units with cell switches and anti-parallel diodes for controlling the voltage contribution, where the full-bridge cells include a bypass switch controllable to bypass the corresponding energy storage element, and when a phase-to-ground fault occurs the cell switches are blocked and the bypass switches activated with a delay in relation to the blocking.

Abstract: A converter arrangement and a method of controlling a three-phase converter arrangement connected to a transmission grid are provided. The converter arrangement includes three phase legs and an energy transfer circuit. The method includes providing a varying respective output phase voltage to the transmission grid by selecting energy storage elements of both the phase legs and the energy transfer circuit and connecting the selected energy storage elements to the transmission grid output. The method further includes selecting energy storage elements for performing a transfer of energy between the energy storage elements during the control period.

Abstract: A converter arrangement and a method of controlling a three-phase converter arrangement connected to a transmission grid are provided. The converter arrangement includes three phase legs and an energy transfer circuit. The method includes providing a varying respective output phase voltage to the transmission grid by selecting energy storage elements of both the phase legs and the energy transfer circuit and connecting the selected energy storage elements to the transmission grid output. The method further includes selecting energy storage elements for performing a transfer of energy between the energy storage elements during the control period.

Abstract: In one aspect of the teachings herein, a self-commutated current source converter is operated in a manner that compensates for the reactive power consumption and/or harmonics generation of a line-commutated current source converter used in the transfer of electrical power between an AC power system and a DC power system. In this regard, the line-commutated current source converter is operated as a first converter in a hybrid converter apparatus and the self-commutated current source converter is operated as a second converter in the hybrid arrangement. According to one example, the first and second converters are stacked, such that each shares a portion of the DC voltage on the DC side of the hybrid converter apparatus, while in another example, the second converter is not used for power conversion and instead is used solely for compensation with respect to the first converter.

Abstract: A converter building including at least one room having a solid room wall enclosing an interior space and an electrical active part contained in the interior space, the room wall having at least one opening, which is designed such that it allows a human to enter the interior space. The opening is sealable, the room wall encloses the interior space in a gas-tight manner when the opening is sealed, and the interior space contains a dielectric insulation medium including a dielectric insulation component other than air.

Abstract: In one aspect of the teachings herein, a self-commutated current source converter is operated in a manner that compensates for the reactive power consumption and/or harmonics generation of a line-commutated current source converter used in the transfer of electrical power between an AC power system and a DC power system. In this regard, the line-commutated current source converter is operated as a first converter in a hybrid converter apparatus and the self-commutated current source converter is operated as a second converter in the hybrid arrangement. According to one example, the first and second converters are stacked, such that each shares a portion of the DC voltage on the DC side of the hybrid converter apparatus, while in another example, the second converter is not used for power conversion and instead is used solely for compensation with respect to the first converter.

Abstract: A cascaded electric power converter and a method of operating a cascaded electric power converter are disclosed. The cascaded converter includes: a converter cell including a cell capacitor and at least one phase leg having at least two electric valves, the at least one phase leg being connected in parallel to the cell capacitor; and a control system for controlling the switching of the electric valves of the at least one phase leg. The control system is configured to, upon detection of a need to by-pass the converter cell, control the switching of the electric valves in a manner so that the cell capacitor is short circuited via a phase leg, so as to obtain a current surge through the phase leg, thereby creating a permanent current path through the converter cell.

Abstract: A photovoltaic system for generating an output voltage that is uninfluenced by varying irradiation, includes a photovoltaic source having an input terminal and an output terminal. The photovoltaic system includes a voltage adding arrangement having a first input terminal and an output terminal. The voltage adding arrangement is connected in series with the photovoltaic source, and includes a first route having a voltage source and a second route as a voltage source bypass. The first and second routes extend between the first input terminal and the output terminal of the voltage adding arrangement. The first and second routes being alternately activateable.

Abstract: A converter building including at least one room having a solid room wall enclosing an interior space and an electrical active part contained in the interior space, the room wall having at least one opening, which is designed such that it allows a human to enter the interior space. The opening is sealable, the room wall encloses the interior space in a gas-tight manner when the opening is sealed, and the interior space contains a dielectric insulation medium including a dielectric insulation component other than air.

Abstract: Voltage source converter based on a chain-link cell topology including one or more phases, each of the phases having one or more series-connected chain-link cell modules connected to each other. The output voltage of the voltage source converter is controlled by control signals applied to the series-connected chain-link cell modules. In case of failure of a chain-link cell module, that module is controlled, by the control signals, such that zero output voltage is provided at its output voltage AC terminal.

Abstract: A cascaded electric power converter and a method of operating a cascaded electric power converter are disclosed. The cascaded converter includes: a converter cell including a cell capacitor and at least one phase leg having at least two electric valves, the at least one phase leg being connected in parallel to the cell capacitor; and a control system for controlling the switching of the electric valves of the at least one phase leg. The control system is configured to, upon detection of a need to by-pass the converter cell, control the switching of the electric valves in a manner so that the cell capacitor is short circuited via a phase leg, so as to obtain a current surge through the phase leg, thereby creating a permanent current path through the converter cell.

Abstract: An arrangement to determine a cell capacitor voltage value of a cell of a multi-cell power converter includes the cell and a control unit. The cell itself includes four power electronic valves interconnected as a full-bridge converter having a first and a second phase leg, where each phase leg includes a series-connection of two of the four power electronic valves and where the connection point between the two power electronic valves of each phase leg is externally connectable, a cell capacitor being connected in parallel to the first and the second phase legs, and four gate units, each being connected to a corresponding one of the power electronic valves as well as to the control unit.

Abstract: Power exchanging arrangement, in shunt connection, with a three-phase electric power network including on one hand for each said phase a reactive impedance element and a Voltage Source Converter connected in series with said element, and on the other hand a control unit configured to control semiconductor devices of turn-off type of said converter for generating a voltage with a fundamental frequency being equal to the fundamental frequency of the voltage of the respective said phase and by that control a flow of reactive power between said arrangement and the respective phase of said electric power network. Each Voltage Source Converter includes a series connection of switching cells in the form of so-called H-bridges including two switching elements connected in parallel and each having at least two semiconductor assemblies connected in series. Each switching cell further comprises at least one energy storing capacitor connected in parallel with said switching elements.

Abstract: Voltage source converter based on a chain-link cell topology including one or more phases, each of the phases having one or more series-connected chain-link cell modules connected to each other. The output voltage of the voltage source converter is controlled by control signals applied to the series-connected chain-link cell modules. In case of failure of a chain-link cell module, that module is controlled, by the control signals, such that zero output voltage is provided at its output voltage AC terminal.

Abstract: An arrangement to determine a cell capacitor voltage value of a cell of a multi-cell power converter includes the cell and a control unit. The cell itself includes four power electronic valves interconnected as a full-bridge converter having a first and a second phase leg, where each phase leg includes a series-connection of two of the four power electronic valves and where the connection point between the two power electronic valves of each phase leg is externally connectable, a cell capacitor being connected in parallel to the first and the second phase legs, and four gate units, each being connected to a corresponding one of the power electronic valves as well as to the control unit.

Abstract: A photovoltaic system for generating an output voltage that is uninfluenced by varying irradiation, includes a photovoltaic source having an input terminal and an output terminal. The photovoltaic system includes a voltage adding arrangement having a first input terminal and an output terminal. The voltage adding arrangement is connected in series with the photovoltaic source, and includes a first route having a voltage source and a second route as a voltage source bypass. The first and second routes extend between the first input terminal and the output terminal of the voltage adding arrangement. The first and second routes being alternately activateable.

Abstract: A voltage source converter for conversion between dc and ac voltage includes at least two serially connected phase legs. The outputs of the conversion stages form phase outputs to be connected to a phase of an alternating voltage network via a respective transformer. The configuration of the conversion stages reduces the requirements on the individual components of the voltage source converter.