Vestas Wind Systems A/s

Vestas Wind Sysiems A/s

Duy Duc Doan

Gert Karmisholt Andersen

John Godsk Nielsen

Lars Helle

Søren Andersen

Ciprian Biris

Kent Tange

Torsten Lund

Tusitha Abeyasekera

Tune Pedersen

Poul Møhl Dyrlund

Cem Özgür Gerçek

Lars Meyer

Amit Kumar Gupta

Kenneth G Hansen

Allan Holm Jørgensen

Hamid Soltani

Hans Christian Bisgaard-Clausen

Hock Heng Thia

Luis Miguel Calhau Gonçalves

Morteza Rabi

Thomas Drljevic-Nielsen

Jens Peter Biltoft

Per Bisgaard

Luis Miguel Calhau GONÇALVES

A system for a wind turbine that includes a protection system interfaced to a circuit breaker system and a sensing system. The protection system is configured to determine an operational mode of the wind turbine by monitoring at least two parameters determine a parameter set comprising a plurality of operational parameters based on a determined operational mode, and an associated set of expected values corresponding to the parameter set, determine actual values corresponding to the determined parameter set, identify a fault condition in the event that the determined set of actual values of the operational parameters do not correspond to the determined set of expected values of the operational parameters, and implement a protection action based on the identified fault condition.

Wind turbine generator fault protection system

This invention concerns a method of controlling a power converter systemoperating in an overmodulation region. The power converter systemcomprises more than two current controllersa modulatorand a power converter, and the modulatoris configured to provide at least one modulated drive signalto the power converterbased on voltage reference vector signalsfrom the more than two current controllers. The method comprises determining the voltage reference vector signals; determining compensated voltage reference vector signalsindicative of a fundamental frequency of a respective voltage reference vector signal; and, determining the at least one modulated drive signalbased on a combination of the compensated voltage reference vector signals

Method of operating a power generation system

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.

Wind turbine with reduced DC-voltage reserve

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.

DC chopper for MMC cell with integrated chopper resistor

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.

Method of operating a power generation system in an overmodulation range

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.

Control of a wind turbine power generation system for optimising DC link voltage

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.

Method of controlling a wind turbine generator

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.

A power conversion system for a wind turbine generator, comprising a machine-side converter having an AC voltage input from a generator and a DC voltage output to a DC link, wherein the machine-side converter is a modular multi-level converter comprising one or more converter legs corresponding to a respective one or more electrical phases of the generator, each of the converter legs comprising a plurality of converter cells, the system further comprising: a converter control module which provides the machine-side converter with a gate signal, and an electrical frequency estimation module configured to estimate the mean electrical frequency of the generator; wherein the gate signal has at least one mean switching frequency corresponding to at least one electrical phase of the generator; wherein the converter control module is configured to modulate the mean switching frequency of the gate signal in dependence on the mean electrical frequency of the generator.

Control system for modular multilevel converter

Controlling a power converters during over voltage condition. A wind turbine signal is monitored for detection of an over voltage of the grid and upon detection of the over voltage, an over-modulation mode is initiated wherein the grid side converter is operated with a modulation index being increased in an over-modulation range at least during a sub-period of the over-modulation mode, and upon the detection of the operational condition, a DC-voltage adjustment mode is initiated wherein the DC voltage of the DC link is decreased from a second voltage level towards a first voltage level at least during a sub-period of the DC-voltage adjustment mode.

Controlling a wind turbine during over-voltage ride through

A method of controlling a wind turbine generator () comprising an electrical generator () and a power converter (), the power converter () comprising an electrical switch () that is configured to process electrical power produced by the electrical generator (), the method comprising: controlling an output from the electrical switch () using a variable pulse-width modulated control signal, thereby to control characteristics of output power from the power converter (); acquiring sample data () relating to an electronic signal within the wind turbine generator (), wherein the sample data () is used for controlling the wind turbine generator (); and dynamically adjusting a frequency () at which the sample data is acquired to synchronise data acquisition with a carrier frequency () of the control signal.

Control of a wind turbine generator for reduced tonal audibility

A power generation system, wind turbine, and method of pulse width modulation (PWM) for power converters are disclosed. The method generally includes generating a substantially random distribution of timing values, applying a filter to the random distribution to produce a modified random distribution, and delivering PWM timing signals based on the modified random distribution to the power converters.

Random pulse width modulation for power converters

A method, converter arrangement, and controller are disclosed for connecting an output of a converter with an electrical grid to control inrush currents into a grid filter assembly connected with the output of the converter, the electrical grid carrying an alternating current (AC) signal having one or more phases. The method includes determining a voltage of the AC signal and operating, after pre-charging a direct current (DC) link of the converter to a predetermined voltage, the converter using open-loop voltage control to produce an AC output signal that substantially matches the AC signal of the electrical grid. The open-loop voltage control is based on the determined voltage of the AC signal. The method further includes closing, after a predetermined amount of time of operating the converter using the open-loop voltage control, a switching device to thereby connect the output of the converter with the electrical grid.

Controlled inrush current for converter-connected grid filter

A wind turbine generatorsupplies three-phase a.c. current of variable voltage and variable frequency to two pairs of rectifiersandwhich generate respective d.c. outputs connected to positive, negative and neutral d.c. conductors. The outputs from each pair of rectifiers are connected together, and the outputs from the two pairs are connected in series to create a high-voltage d.c. output. Invertersthen convert the d.c. power to a.c. at a fixed frequency and voltage suitable for connection to the mains grid. To reduce the effect of common-mode noise, a capacitor is connected between the 1 neutral conductorand earth, and a respective filter circuitis connected between each of the a.c. outputs of the invertersand earth. To reduce the effect of voltage surges during lightning, a surge protection device is also connected between the neutral d.c. conductorand earth. Any imbalance in the current in the positive and negative conductorsis compensated by detecting the presence of current flowing in the neutral conductor. Power supplied to auxiliary circuits from the output of one of the inverters, e.g., of the wind turbine is measured, and any resulting imbalance between the current in the positive and negative conductors is compensated. In the event of an earth-leakage fault in the conductors connecting the a.c. outputs of the inverters to the grid, when isolated, isolation detection relaysare provided.

Converters for wind turbine generators

The present invention relates to a method for shutting down a wind power facility, said wind power facility comprising a power generator, a power converter comprising generator side and grid side converters being separated by an intermediate DC circuit, and power dissipation or power storage means being operatively connected to the intermediate DC circuit, the method comprising the steps of determining that the wind power facility needs to be shut down, and operating the generator side converter in accordance with a load time curve during shutdown of the wind power facility in order to avoid overloading of selected generator side converter components and the power dissipation or power storage means. Moreover, the present invention relates to a wind power facility for performing this method.

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Tilst, Denmark

Duy Duc Doan