Abstract:
The present invention relates to a method for operating a wind power facility in order to provide reactive power support to a power grid, the method comprising the step of 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 essentially said certain amount of active power in power dissipation and/or power storage means. The wind power facility may comprise a wind turbine or a wind power plant.
Abstract:
According to an embodiment, a method of operating a wind turbine comprising a DC-to-AC voltage converter is provided, the wind turbine being connectable to a grid via the DC-to-AC voltage converter, the method comprising: determining a line voltage of a power line connecting the DC-to-AC voltage converter to the grid; if the determined line voltage exceeds a predefined voltage threshold value, injecting reactive current into the power line, wherein the amount of reactive current injected is chosen such that an output voltage of the DC-to-AC voltage converter is kept within a predetermined voltage range.
Abstract:
A method for controlling a power converter in a wind turbine generator, the power converter being connected to a power grid, the method comprising obtaining an alternating current (AC) line voltage at a connection point between the power converter and the power grid, obtaining a frequency of the power grid based on the AC line voltage, dynamically adapting the AC line voltage to the frequency of the power grid, generating a reference signal based on at least the frequency-adapted AC line voltage, and determining a converter control signal to be provided to the power converter based on the reference signal and the grid frequency in order to generate a power at the frequency of the power grid. Further, a wind turbine generator implementing the method is provided.
Abstract:
A method of controlling a wind turbine generator is provided, the wind turbine generator converting mechanical energy to electrical. The method comprises: determining an electromagnetic power reference representing the electromagnetic power generated by the wind turbine generator, wherein the electromagnetic power reference is determined based on a desired output of the wind turbine generator; controlling the electrical power generated by the wind turbine generator using a control signal, wherein the control signal is derived from the electromagnetic power reference and is modified in dependence on an inverse power function of the wind turbine generator by incorporating minimal copper loss constraint and stator voltage limiting constraint such that non-linearity of the wind turbine generator plant is compensated in the control loop and it operates at its maximum efficiency. One effect of the method is that classical linear control loop design can be employed in spite of the plant being a non-linear identity.
Abstract:
A method for controlling a variable speed wind turbine generator is disclosed. The generator is connected to a power converter comprising switches. The generator comprises a stator and a set of terminals connected to the stator and to the switches of the power converter. The method comprises: determining a stator flux reference value corresponding to a generator power of a desired magnitude, determining an estimated stator flux value corresponding to an actual generator power, determining a difference between the determined stator flux reference value and the estimated stator flux value, and operating said switches in correspondence to the determined stator flux reference value and the estimated stator flux value to adapt at least one stator electrical quantity to obtain said desired generator power magnitude.
Abstract:
An off grid electric system for charging electric vehicles. A plurality of wind turbines (WT1, WT2, WT3, WT4) serve to generate respective electric power outputs, and an electric storage system (BTS), e.g. Li-ion batteries, is arranged to store electric power generated by the wind turbines. A plurality of electric vehicle charging stations (VC1, VC2, VC3, VC4) 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). In preferred embodiments, the wind turbines have permanent magnet generators that generate Medium Voltage AC outputs, e.g. 4-8 kV, and generate Medium Voltage DC outputs by means of a DC-DC converter placed down-tower. In some embodiments the DC-DC converter is placed in a kiosk near the wind turbine, whereas the EV charging stations are placed 25-500 m further away from the wind turbine. Such off grid wind turbine systems are feasible for e.g. charging of large fleets of EVs, especially in embodiments where a weather forecast is used to control electric power distribution between electric storage and wind turbines in response to a prediction of available wind turbine electric power.
Abstract:
The present invention relates to wind energy park connected to an electrical grid, having airborne wind energy systems (AWES, 100), e.g. with kites (101). The wind energy park (WEP) has an electrical DC network (506) connecting the plurality of AWES and a grid converter unit (504) for converting DC to AC, and transmit AC to the electrical grid. The wind energy park control unit (503) 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 stabilises the grid and has a grid forming capability.
Abstract:
A method for use in controlling a wind turbine generator (1) 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 (1). 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:
A method of controlling a wind turbine generator (1) comprising an electrical generator (10) and a power converter (12), the power converter (12) comprising an electrical switch (14a, 14b) that is configured to process electrical power produced by the electrical generator (10), the method comprising: controlling an output from the electrical switch (14a, 14b) using a variable pulse-width modulated control signal, thereby to control characteristics of output power from the power converter (12); acquiring sample data (26) relating to an electronic signal within the wind turbine generator (1), wherein the sample data (26) is used for controlling the wind turbine generator (1); and dynamically adjusting a frequency (30) at which the sample data is acquired to synchronise data acquisition with a carrier frequency (24) of the control signal.
Abstract:
According to an embodiment of the present invention, a method of operating a wind turbine including a power generator, a generator/machine side converter connected to the power generator, a grid/line side converter connected to a power grid through power components, and a DC-link connected between the machine side converter and the line side converter, comprises: Monitoring the power grid for overvoltage events; if an overvoltage event is detected disabling active operation of the machine side converter and of the line side converter, enabling an AC- load dump connected between the machine side converter and the power generator in order to dissipate active power output by the power generator into the AC-load dump, waiting for a waiting period, and enabling active operation of the line side converter and the machine side converter if the overvoltage ends within the waiting period.