Abstract: An off-grid wind turbine system comprising a wind turbine with an electric generator for generating an initial electric power output. An electrolyzer system with a hydrogen electrolyzer located inside the nacelle or tower of the wind turbine, so as to generate hydrogen by an electrolysis process. An electric converter system serves to convert the initial electric power output into a DC electric power output dedicated for powering the electrolyzer. The produced hydrogen is stored in a hydrogen storage tank.

Abstract: A method of operating a power generating system for a wind turbine connected to an electrical grid, the power generating system comprising a power generator, a converter, a transformer and a tap changer, the method comprising; when operating the power generating system in a grid-forming configuration, monitoring a signal for detecting a voltage of the electrical grid which requires an increase in output voltage from the power generating system in order to maintain the grid voltage within a predetermined voltage range; and operating the tap changer to tap-up the transformer to provide at least part of the voltage increase required to maintain the grid voltage within the predetermined voltage range.

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: The invention relates to a method for controlling a wind turbine which comprises a transformer has a variable turns ratio such as an on load tap changer transformer. The adjustment of the turns ratio is possible when a primary side current or a secondary side current of the transformer is less than a switching current threshold. The method comprises operating the wind turbine so that the primary or secondary side current is above the switching current threshold. In response to obtaining a condition for changing the turns ratio of the transformer, the wind turbine is operated so that the primary or secondary side current is reduced below the switching current threshold so that the turns ratio can be changed during the temporary current reduction.

Abstract: A method, controller, wind power plant, and computer program product are disclosed for operating a wind power plant comprising a plurality of wind turbines, the wind power plant producing a plant power output. The method comprises receiving a modulation request signal indicating a requested modulation of the plant power output, the requested modulation specifying a modulation frequency. The method further comprises generating a respective power reference signal for each of at least two wind turbines of the plurality of wind turbines selected to fulfill the requested modulation, Each generated power reference signal includes a respective modulation component corresponding to a portion of the requested modulation and having a frequency different than the modulation frequency.

Abstract: Embodiments herein describe a power converter in a wind turbine that includes a rectifier and an inverter. The rectifier includes a plurality of phase legs where each phase leg includes a plurality of full bridge cells configured to block fault current from flowing from a generator through the rectifier. Moreover, the wind turbine does not have any circuit breaker between the rectifier and the generator. The inverter also includes a plurality of phase legs where each phase leg includes a plurality of full bridge cells configured to block fault current from flowing from a transformer through the inverter. Moreover, the wind turbine does not have any circuit breaker between the inverter and the transformer.

Abstract: A DC to DC power converter is described that includes a transformer, a primary side connected to a primary transformer winding, and a secondary side connected to a secondary transformer winding. The secondary side comprises inductor-capacitor (LC) circuitry at an input, and a plurality of diodes providing uncontrolled rectification. A controller controls switching of the switching circuitry to apply voltage pulses to the primary transformer winding. The voltage pulses are separated by zero-voltage periods. A switching frequency of the switching circuitry is less than the resonant frequency of the LC circuitry.

Abstract: The invention relates to a method for controlling a wind turbine which comprises a transformer has a variable turns ratio such as an on load tap changer transformer. The adjustment of the turns ratio is possible when a primary side current or a secondary side current of the transformer is less than a switching current threshold. The method comprises operating the wind turbine so that the primary or secondary side current is above the switching current threshold. In response to obtaining a condition for changing the turns ratio of the transformer, the wind turbine is operated so that the primary or secondary side current is reduced below the switching current threshold so that the turns ratio can be changed during the temporary current reduction.

Abstract: The invention relates to a method for controlling a wind turbine configured with an on load tap changer transformer which enables adjustment of a current ratio of a primary side current of the transformer and a secondary side current of the transformer. The method comprises detecting that a network voltage on the primary side or secondary side of the transformer is outside a pre-determined voltage range, and in response determining a current reference for the primary side current based on the detected network voltage. The power converter of the wind turbine is controlled to generate an increase of the primary side current towards the current reference, and the current ratio of the transformer is adjusted towards a higher ratio of the current ratio.

Abstract: The invention relates to a method for controlling a wind turbine which comprises a transformer has a variable turns ratio such as an on load tap changer transformer. The adjustment of the turns ratio is possible when a primary side current or a secondary side current of the transformer is less than a switching current threshold. The method comprises operating the wind turbine so that the primary or secondary side current is above the switching current threshold. In response to obtaining a condition for changing the turns ratio of the transformer, the wind turbine is operated so that the primary or secondary side current is reduced below the switching current threshold so that the turns ratio can be changed during the temporary current reduction.

Abstract: A wind turbine power generation system comprising a rotor shaft coupled to an electrical generator which generates a power output at a first AC voltage level; a converter system that converts the power output of the generator at the first AC voltage level to a converter power output at a second AC voltage level; a transformer that converts the converter system power output at the second AC voltage level to a generation system power output at a third AC voltage level; wherein the converter system comprises a machine-side converter, a line-side converter and a DC-link. The machine-side converter is a line-commutated rectifier, and the transformer is an online tap changer transformer. In another aspect, the invention resides in a wind power plant comprising at least one wind power generation system electrically coupled to a substation for onward transmission to a grid.

Abstract: Embodiments herein describe a power converter in a wind turbine that includes a rectifier and an inverter. The rectifier includes a plurality of phase legs where each phase leg includes a plurality of full bridge cells configured to block fault current from flowing from a generator through the rectifier. Moreover, the wind turbine does not have any circuit breaker between the rectifier and the generator. The inverter also includes a plurality of phase legs where each phase leg includes a plurality of full bridge cells configured to block fault current from flowing from a transformer through the inverter. Moreover, the wind turbine does not have any circuit breaker between the inverter and the transformer.

Abstract: The invention relates to a method for controlling a wind turbine which comprises a transformer has a variable turns ratio such as an on load tap changer transformer. The adjustment of the turns ratio is possible when a primary side current or a secondary side current of the transformer is less than a switching current threshold. The method comprises operating the wind turbine so that the primary or secondary side current is above the switching current threshold. In response to obtaining a condition for changing the turns ratio of the transformer, the wind turbine is operated so that the primary or secondary side current is reduced below the switching current threshold so that the turns ratio can be changed during the temporary current reduction.

Abstract: The invention relates to a method for controlling a wind turbine configured with an on load tap changer transformer which enables adjustment of a current ratio of a primary side current of the transformer and a secondary side current of the transformer. The method comprises detecting that a network voltage on the primary side or secondary side of the transformer is outside a pre-determined voltage range, and in response determining a current reference for the primary side current based on the detected network voltage. The power converter of the wind turbine is controlled to generate an increase of the primary side current towards the current reference, and the current ratio of the transformer is adjusted towards a higher ratio of the current ratio.

Abstract: A method, controller, wind power plant, and computer program product are disclosed for operating a wind power plant comprising a plurality of wind turbines, the wind power plant producing a plant power output. The method comprises receiving a modulation request signal indicating a requested modulation of the plant power output, the requested modulation specifying a modulation frequency. The method further comprises generating a respective power reference signal for each of at least two wind turbines of the plurality of wind turbines selected to fulfill the requested modulation, Each generated power reference signal includes a respective modulation component corresponding to a portion of the requested modulation and having a frequency different than the modulation frequency.

Abstract: A conventional cable comprises three conductive cores, each provided with a respective conductive sheath which are together housed within an outer insulating sheath. The three-core cable is used to transmit electric power in the form of dc current and single-phase ac current. A first one of the conductive cores is used to transmit dc current, while a second conductive core is used to transmit the return dc current. The third conductive core is used to transmit the single-phase ac current. The return ac current is transmitted along all three conductive outer sheaths in parallel. The cable is used to transmit dc current from a wind turbine generator to a substation where it is converted to ac before connecting to the mains electricity grid. The ac current is used to power auxiliary circuitry of the wind turbine generator when the output of the turbine generator falls below a give value.

Abstract: A wind turbine power generation system comprising a rotor shaft coupled to an electrical generator which generates a power output at a first AC voltage level; a converter system that converts the power output of the generator at the first AC voltage level to a converter power output at a second AC voltage level; a transformer that converts the converter system power output at the second AC voltage level to a generation system power output at a third AC voltage level; wherein the converter system comprises a machine-side converter, a line-side converter and a DC-link. The machine-side converter is a line-commutated rectifier, and the transformer is an online tap changer transformer. In another aspect, the invention resides in a wind power plant comprising at least one wind power generation system electrically coupled to a substation for onward transmission to a grid.

Abstract: The present invention relates to method for operating a power plant, with at least one wind turbine generator arranged for supplying power to an electrical grid, at least one energy storage device arranged for supplying power to the electrical grid, and a power plant controller, the method comprises, measuring repetitively measurement sets of at least one electrical parameter from the electrical grid, and calculating, in respect the measurement sets of the at least one electrical parameter, a change in active and/or a required change in reactive power at a point of common coupling, and calculating and dispatching of a first control reference signal to the at least one wind turbine generator and a second control reference signal to the at least one energy storage device, for providing ancillary service functionalities to the electrical grid.

Abstract: The present invention relates to a connection system for connecting a power generator to a DC electrical power system, with a controllable voltage source unit functionally connected in series with the power generator to receive AC electrical power from the power generator, and to generate an AC electrical power output accordingly, and a rectifier arranged to receive AC electrical power output from said voltage source unit and to rectify the AC electrical power output to a DC electrical power to be provided to the DC electrical power system. The invention also relates to method for connecting a power generator to a DC electrical power system.

Abstract: The present invention relates to a fault-tolerant control system for a wind turbine comprising a plurality of controllable wind turbine components, the control system comprising control means for generating a replica of essentially concurrent set-point values, a data communication network for transmitting the replica of essentially concurrent set-point values to the plurality of wind turbine components, and a plurality of decentralized voting means being arranged so that a decentralized voting means is assigned to each wind turbine component, each decentralized voting means being adapted to select one set-point value out of the replica of set-point values. The present invention further relates to a wind turbine and to an associated method.