Abstract: A wind turbine system with a medium voltage (MV) converter system for converting electric power by the wind turbine generator. A housing, e.g. a placed on the ground near the wind turbine tower, encloses the MV converter to block access. An access door with a controllable locking mechanism is controlled by an access control system which unlocks the access door after execution of a safety access algorithm. This allows a person to provide service to the potentially dangerous MV equipment in a safe an automated way after request. The housing preferably has a control compartment where a person can request access and await opening of the access door for safe access to the MV converter.

Abstract: This disclosure proposes procedures and systems for discharging system capacitors and de-energizing power transmission systems having Modular Multilevel Converter (MMC) topologies by intelligent control of MMC cell components including configuration of bypass and insert switches using integrated DC choppers to effectively de-energize MMC cell capacitors and/or DC-link capacitors under operating conditions such as after a normal stop, for protection against over-voltages, dumping turbine energy, and under certain hardware fault conditions.

Abstract: A wind turbine system with a medium voltage (MV) converter system for converting electric power by the wind turbine generator. A housing, e.g. a placed on the ground near the wind turbine tower, encloses the MV converter to block access. An access door with a controllable locking mechanism is controlled by an access control system which unlocks the access door after execution of a safety access algorithm. This allows a person to provide service to the potentially dangerous MV equipment in a safe an automated way after request. The housing preferably has a control compartment where a person can request access and await opening of the access door for safe access to the MV converter.

Abstract: According to embodiments described herein a Modular Multilevel Converter (MMC) is pre-charged by: driving a bypass current from an auxiliary power source through a plurality of bypass switches included in a corresponding plurality of cells; in response to a summed voltage across a plurality of cell capacitors included in the plurality of cells satisfying a drive threshold, driving an insert current through a plurality of insert switches included in the plurality of cells; and in response to a voltage across a Direct Current (DC) link capacitor satisfying a pre-charge threshold when driving the insert current, opening a circuit breaker connecting the auxiliary power source with the plurality of cells and connecting a generator with external power line rails between which the DC link capacitor is connected.

Abstract: An off grid electric system for charging electric vehicles. An electric storage system (BTS) is arranged to store electric power generated by a plurality of wind turbines. A plurality of electric vehicle charging stations are connected to the plurality of wind turbines, and the electric storage system by means of an off grid electric power network (CN), so as to allow each charging station to charge at least one electric vehicle (EV).

Abstract: This disclosure proposes a topology that integrates a DC chopper into the Modular Multilevel Converter (MMC) cells of a power converter. The integrated DC chopper may include chopper resistors that may also be advantageously integrated into a heat sink for a power module including at least the power transistors of the MMC cell. Embodiments herein also describe a method for using an MMC cell's IGBTs and chopper resistors for providing a safe discharge of both cell capacitors and DC-link capacitors in different operating conditions.

Abstract: This disclosure proposes procedures and systems for discharging system capacitors and de-energizing power transmission systems having Modular Multilevel Converter (MMC) topologies by intelligent control of MMC cell components including configuration of bypass and insert switches using integrated DC choppers to effectively de-energize MMC cell capacitors and/or DC-link capacitors under operating conditions such as after a normal stop, for protection against over-voltages, dumping turbine energy, and under certain hardware fault conditions.

Abstract: According to embodiments described herein a Modular Multilevel Converter (MMC) is pre-charged by: driving a bypass current from an auxiliary power source through a plurality of bypass switches included in a corresponding plurality of cells; in response to a summed voltage across a plurality of cell capacitors included in the plurality of cells satisfying a drive threshold, driving an insert current through a plurality of insert switches included in the plurality of cells; and in response to a voltage across a Direct Current (DC) link capacitor satisfying a pre-charge threshold when driving the insert current, opening a circuit breaker connecting the auxiliary power source with the plurality of cells and connecting a generator with external power line rails between which the DC link capacitor is connected.

Abstract: The present invention relates to wind energy park connected to an electrical grid, having airborne wind energy systems (AWES), e.g. with kites. The wind energy park has an electrical DC network connecting the plurality of AWES and a grid converter unit for converting DC to AC, and transmit AC to the electrical grid. The wind energy park control unit controls the AWES to produce electrical power to the electrical grid by alternating between a power production phase, and a recovery phase so to balance the supply of power to the electrical grid according a demanded setpoint. An advantage is that the grid converter may be smaller, as compared to an AC network, because the power is evened out with the negative power from the AWES being in recovery phase. In this way, the invention stabilizes the grid and has a grid forming capability.

Abstract: This disclosure proposes a topology that integrates a DC chopper into the Modular Multilevel Converter (MMC) cells of a power converter. The integrated DC chopper may include chopper resistors that may also be advantageously integrated into a heat sink for a power module comprising at least the power transistors of the MMC cell. Embodiments herein also describe a method for using an MMC cell's IGBTs and chopper resistors for providing a safe discharge of both cell capacitors and DC-link capacitors in different operating conditions.

Abstract: A method for use in controlling a wind turbine generator of a wind power plant based on a condition of a power converter or a component forming part of a power converter in the wind power plant. The method comprises determining the initial condition of the power converter or a component forming part of a power converter and determining the evolution of the condition from the initial condition based on notional power reference values of the wind turbine generator. The method further comprises comparing the evolution of the condition to a predetermined threshold and determining, from the comparison, a time period by which the condition of the power converter or a component forming part of a power converter will substantially equal the predetermined threshold.

Abstract: The present invention relates to a method for simultaneous operation of a plurality of chopper circuits of a wind turbine power converter, the method comprising the steps of operating a controllable switching member of a first chopper circuit in accordance with a first switching pattern, and operating a controllable switching member of a second chopper circuit in accordance with a second switching pattern, wherein the first switching pattern is different from the second switching pattern during a first time period. In order to reduce switching losses the first switching pattern may involve that the controllable switching member of the first chopper circuit is clamped during the first time period. Additional chopper circuits may be provided in parallel to the first and second chopper circuits. The present invention further relates to a power dissipation chopper being operated in accordance with the before mentioned method.

Abstract: A Direct Current (DC) chopper may be integrated into the Modular Multilevel Converter (MMC) cells of a power converter. The integrated DC chopper may include chopper resistors that may also be advantageously integrated into a heat sink for a power module including at least the power transistors of the MMC cell. The safe discharge of both cell capacitors and DC-link capacitors in different operating conditions is performed using Insulated-Gate Bipolar Transistors (IGBTs) and chopper resistors of an MMC cell.

Abstract: The present invention relates to operation of a wind turbine using a power storage unit, such as a rechargeable battery, to power a group of power consuming units during grid loss. The wind turbine comprises a number of power consuming units being grouped into at least a first group and a second group, a first electrical converter for connecting the generator to the electrical grid, and a second electrical converter for connecting the electrical generator to the power storage unit. Upon detecting an occurrence of the grid loss, the generator is operated to ensure sufficient power of the power storage unit to operate the first group of power consuming units.

Abstract: A method for use in controlling a wind turbine generator based on a condition of a power converter or a component forming part of a power converter in the wind turbine generator. The method comprises determining a condition of the power converter or the component forming part of a power converter, then comparing the condition to a predetermined threshold and modifying an operational parameter of the wind turbine generator if the condition substantially equals or exceeds the predetermined threshold. In particular, the invention proposes the wind turbine generator is derated if the condition of the power converter or the component forming part of a power converter substantially equals or exceeds the predetermined threshold.

Abstract: This disclosure proposes a topology that integrates a DC chopper into the Modular Multilevel Converter (MMC) cells of a power converter. The integrated DC chopper may include chopper resistors that may also be advantageously integrated into a heat sink for a power module comprising at least the power transistors of the MMC cell. Embodiments herein also describe a method for using an MMC cell's IGBTs and chopper resistors for providing a safe discharge of both cell capacitors and DC-link capacitors in different operating conditions.

Abstract: Aspects of the present disclosure are generally directed to configurations of power conversion systems for wind turbine generators. For example, certain aspects are directed to a multi-rotor wind turbine. The multi-rotor wind turbine generally includes a plurality of rotors, each coupled to a plurality of electrical generators, one or more machine-side converters, MSCs, coupled to the electrical generators of each of the plurality of rotors and configured to generate at least one direct-current, DC, signal, and one or more line-side converters, LSCs, coupled to the MSCs and configured to generate at least one AC signal based on the at least one DC signal.

Abstract: The present invention relates to wind energy park connected to an electrical grid, having airborne wind energy systems (AWES), e.g. with kites. The wind energy park has an electrical DC network connecting the plurality of AWES and a grid converter unit for converting DC to AC, and transmit AC to the electrical grid. The wind energy park control unit controls the AWES to produce electrical power to the electrical grid by alternating between a power production phase, and a recovery phase so to balance the supply of power to the electrical grid according a demanded setpoint. An advantage is that the grid converter may be smaller, as compared to an AC network, because the power is evened out with the negative power from the AWES being in recovery phase. In this way, the invention stabilizes the grid and has a grid forming capability.

Abstract: A method for use in controlling a wind turbine generator of a wind power plant based on a condition of a power converter or a component forming part of a power converter in the wind power plant. The method comprises determining the initial condition of the power converter or a component forming part of a power converter and determining the evolution of the condition from the initial condition based on notional power reference values of the wind turbine generator. The method further comprises comparing the evolution of the condition to a predetermined threshold and determining, from the comparison, a time period by which the condition of the power converter or a component forming part of a power converter will substantially equal the predetermined threshold.

Abstract: The present invention relates to a method for simultaneous operation of a plurality of chopper circuits of a wind turbine power converter, the method comprising the steps of operating a controllable switching member of a first chopper circuit in accordance with a first switching pattern, and operating a controllable switching member of a second chopper circuit in accordance with a second switching pattern, wherein the first switching pattern is different from the second switching pattern during a first time period. In order to reduce switching losses the first switching pattern may involve that the controllable switching member of the first chopper circuit is clamped during the first time period. Additional chopper circuits may be provided in parallel to the first and second chopper circuits. The present invention further relates to a power dissipation chopper being operated in accordance with the before mentioned method.