Vestas Wind Systems A/s

Søren Andersen

Duy Duc Doan

John Godsk Nielsen

Lars Helle

Gert Karmisholt Andersen

Tusitha Abeyasekera

Anshuman Tripathi

Shu Yu Cao

Kent Tange

Victor Donescu

Tune Pedersen

Allan Holm Jørgensen

Rasool Beevi D-o Mohamed Arif

Jens Peter Biltoft

Thomas Drljevic-Nielsen

Rasool Beevi D-O Mohamed Arif

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

A method of controlling a full-scale converter system in which both the grid-side inverter unit and the generator-side inverter unit have a series-connection of parallel inverters and form a generator-side and grid-side voltage-center-point at a voltage level between the inverters connected in series. The voltage-center-points are electrically connected by a center-line conductor. Conversion operation with a de-rated maximum active power-output is performed in response to at least one of (i) the grid-side inverter and (ii) the generator-side inverter of the first converter-string being disabled, by disabling active power production of at least one of (i) the grid-side inverter and (ii) the generator-side inverter of the second converter-string, or correspondingly reducing active power production of the second converter-string, thereby preventing a compensation current along the center-line conductor.

Wind turbine converter control

A wind turbine converter system with a rectifier and an inverter and a converter controller has at least first and second converter strings. The converter system is controlled by a master-converter controller and a slave-converter controller. The master-converter controller controls the first converter string and the slave-converter controller controls the second converter string. The master-converter controller receives commands from a superordinate wind turbine controller, provides the slave-converter controller with string-control commands on the basis of the superordinate control commands, and controls the conversion operation of the first converter string on the basis of the superordinate control command. The slave-converter controller receives the string-control commands from the master-converter controller and controls the conversion operation of the second converter string on the basis of the string-control commands received. The first and the second converter strings can be arranged in a bipolar configuration giving access to a neutral point. Fault detection can be performed based on current through the neutral. The system is capable of fault ride-through. Also, in case of failure of the master-converter controller, a redundant unit takes its place.

Wind-turbine converter control for modular string converters

In a full-scale converter system both the grid-side inverter unit and the generator-side inverter unit have a series convection of parallel inverters and form a generator-side and grid-side voltage-center-point at a voltage level between those of the inverters connected in series. The voltage-center-points are electrically connected by a center-line conductor that has a cross-section between 30% and 70% of that of a positive or negative potential conductor. The converter system continues conversion operation in the event of a fault in an inverter of a first converter-string, with non-faulty inverters of the converter system, as the center-line conductor is dimensioned by said cross-section to carry a compensation current resulting from an unbalanced active power-output.

Fault tolerant wind turbine converter system

A method of monitoring a split wind-turbine-converter system with at least one generator-side converter and at least one grid-side converter arranged at distant locations, and a DC-link in the form of an elongated conductor arrangement with at least one positive and at least one negative conductor. The impedance of the DC-link conductor arrangement is determined by means of DC-voltage sensors. The voltages between the positive and the negative conductors are determined at the generator-side converter and at the grid-side converter, and the difference between the voltages is determined. The impedance of the DC-link conductor arrangement is determined by putting the determined voltage difference in relation to the DC current flowing through the DC-link conductor arrangement. If the impedance exceeds a given impedance threshold a fault state is recognized.

Monitoring of a DC-link of a split wind-turbine-converter system

Techniques are described for operating a wind power facility in order to provide reactive power support to a power grid. The wind power facility may be a wind turbine or a wind power plant. An exemplary method includes increasing an amount of reactive power injected into the power grid, decreasing an amount of active power injected into the power grid by a certain amount, and dissipating and/or storing substantially the certain amount of active power.

Reactive power support from wind turbine facilities

A method of setting a reference DC-link voltage of a wind-turbine converter system is provided. At least at least one DC voltage demand from at least one generator-side inverter and at least one DC voltage demand are received from at least one grid-side inverter. A generator-side DC voltage demand value on the basis of the at least one DC voltage demand received from the at least one generator-side inverter. Also a grid-side DC voltage demand value is determined on the basis of the at least one DC voltage demand received from the at least one grid-side inverter. The highest DC voltage demand value out of the generator-side and grid-side DC voltage demand values is chosen. This chosen value corresponds to the set reference DC-link voltage.

DC-link reference voltage determination for wind turbine converter systems

A method for operating an electromechanical generator is provided, the method comprising: determining a magnetic field reference parameter based on an electromagnetic power reference representing a desired output of the electromechanical generator, determining a scaling factor for adjusting an air-gap magnetization level of the electromechanical generator to reduce loss in operating the electromechanical generator, modifying the magnetic field reference parameter with the scaling factor; and operating the electromechanical generator based on at least the modified magnetic field reference parameter.

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Tilst, Denmark

Søren Andersen