Abstract: A wind turbine generator (100a-e) comprising an electric generator (102) and an apparatus (104a-e) for electric power conversion, wherein the apparatus (104a-e) comprises: a first power converter (106) for converting AC power from the electric generator (102) to DC power; a second power converter (108) for converting DC power from the first power converter (106) to AC power to be provided to an electric power grid (110); a DC link (112) comprising a positive rail (114) and a negative rail (116) connecting the first power converter (106) to the second power converter (118); and an energy storage arrangement (118a-d) comprising multiple supercapacitors (120) connected or connectable to the DC link (112) so as to support the operation of one or more of the first and second power converters (106, 108). The energy storage arrangement (118a-d) comprises one or more DC-to-DC converters (122) for connecting one or more of the supercapacitors (122) of the energy storage arrangement (118a-d) to the DC link (112).

Abstract: A method for tracking a gear tooth meshing angle of a gearbox of a wind turbine is disclosed. An initial reference virtual gear tooth meshing angle of the gearbox is selected, and an angular position of a high speed shaft and/or a low speed shaft of the gearbox is monitored. A virtual gear tooth meshing angle relative to the reference virtual gear tooth meshing angle is estimated, based on the monitored angular position of the high speed shaft and/or the low speed shaft and on information regarding topology of the gearbox. A number of full rotations of the high speed shaft and/or the low speed shaft which corresponds to an integer number of full periods of gear meshing of the gearbox is calculated, and the reference virtual gear tooth meshing angle is reset each time the high speed shaft and/or the low speed shaft has performed the calculated number of full rotations. The estimated virtual gear tooth meshing angle is applied to a periodic noise signal of the wind turbine.

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; monitoring a signal for detecting an over-voltage condition in the electrical grid which requires a reduction in the output voltage from the power generating system; initiating a convertor response mode configured to provide at least part of the required voltage reduction; and initiating a transformer response mode configured to provide at least part of the required voltage reduction; wherein the transformer response mode comprises operating the tap changer to adjust the output voltage from the power generating system.

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: 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: Method and apparatus for monitoring a wind turbine having an electrical component. An exterior temperature and power loss associated with the electrical component is obtained, and a thermal model describing the electrical component is executed, based on the exterior temperature and power loss, to determine an internal temperature of the electrical component. A further thermal model describing the electrical component is executed, based on the internal temperature and an exterior component temperature, to predict a future thermal condition of the electrical component in order to monitor operation of the wind turbine.

Abstract: This invention concerns a method of controlling a power converter system 26 operating in an overmodulation region. The power converter system 26 comprises more than two current controllers 71, 73, 77, 79 a modulator 76 and a power converter 78, and the modulator 76 is configured to provide at least one modulated drive signal 87 to the power converter 78 based on voltage reference vector signals 82a, 82b, 82c, 82d from the more than two current controllers 71, 73, 77, 79. The method comprises determining the voltage reference vector signals 82a, 82b, 82c, 82d; determining compensated voltage reference vector signals 84a, 84b, 84c, 84d indicative of a fundamental frequency of a respective voltage reference vector signal 82a, 82b, 82c, 82d; and, determining the at least one modulated drive signal 87 based on a combination of the compensated voltage reference vector signals 84a, 84b, 84c, 84d.

Abstract: The invention relates to monitoring a wind turbine having an electrical component. An exterior temperature and power loss associated with the electrical component is obtained, and a thermal model describing the electrical component is executed, based on the exterior temperature and power loss, to determine an internal temperature of the electrical component. A further thermal model describing the electrical component is executed, based on the internal temperature and an exterior component temperature, to predict a future thermal condition of the electrical component in order to monitor operation of the wind turbine.

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: The invention relates to a method for operating a wind turbine which comprises a power generator, a generator side converter, a grid side converter, a DC link electrically connected to an output of the generator side converter and an input of the grid side converter. The method comprises monitoring a wind turbine signal for detection of an operational condition which requires an increase of an output voltage of the grid side converter, upon detection of the operational condition, initiate an over-modulation mode wherein the grid side converter is operated with a modulation index in an over-modulation range, and upon the detection of the operational condition, initiate a DC-voltage adjustment mode wherein the a DC-voltage of the DC link is increased from a first voltage level towards a second voltage level.

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; monitoring a signal for detecting an over-voltage condition in the electrical grid which requires a reduction in the output voltage from the power generating system; initiating a convertor response mode configured to provide at least part of the required voltage reduction; and initiating a transformer response mode configured to provide at least part of the required voltage reduction; wherein the transformer response mode comprises operating the tap changer to adjust the output voltage from the power generating system.

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 invention concerns a method of controlling a line side converter of a power converter system operating in an over-modulation range. The line side converter comprises a controller comprising a feedback control module configured to output a feedback control signal for modifying a drive signal received by a modulator. The method comprises determining a modulation index within the over-modulation range; and, controlling the feedback control module to adjust the feedback control signal based on the modulation index.

Abstract: This invention relates to a method of controlling at least one wind turbine of a plurality of wind turbines connected to an electrical grid at a predefined point in the electrical grid. The wind turbine comprises a DC link connecting a generator side converter to a line side converter, where the line side converter is controlled according to a modulation index requested by a power converter controller. The method comprises determining a harmonic frequency signal indicative of a harmonic frequency value at the predefined point in the electrical grid; determining a deviation between the harmonic frequency signal and a permissible harmonic frequency value; determining a permissible modulation index based on the deviation; comparing the permissible modulation index to the modulation index requested by the power converter controller; and, altering a DC link voltage set-point based on the comparison between the permissible modulation index and the requested modulation index.

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 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; monitoring a signal for detecting a voltage in the electrical grid which requires an increase in output voltage from the power generating system; determining a partial-load condition of the converter, which corresponds to the converter being configured to output a voltage which is substantially below its maximum output voltage; and upon determining the partial-load condition, operating the tap changer to tap down the transformer, and operating the converter to provide the required increase in output voltage from the power generating system.

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 invention relate to a method for controlling an amount of reactive current provided from a wind turbine generator to a power grid during an abnormal power grid event, said wind turbine generator comprising a doubly-fed induction generator having a rotor and a stator, and a power converter coupling the rotor to the power grid, the power converter comprising a grid-side inverter, wherein the method comprises the step of balancing the reactive current provided to the power grid between a reactive stator current and a reactive grid-side inverter current, wherein the reactive grid-side inverter current is controlled in accordance with a reactive current capacity of a grid breaker receiving the reactive current provided by the grid-side inverter. Aspects of the present invention also relate to a wind turbine generator being capable of performing the 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: This invention concerns a method of controlling a line side converter of a power converter system operating in an over-modulation range. The line side converter comprises a controller comprising a feedback control module configured to output a feedback control signal for modifying a drive signal received by a modulator. The method comprises determining a modulation index within the over-modulation range; and, controlling the feedback control module to adjust the feedback control signal based on the modulation index.