WIND TURBINE WITH AN AUXILIARY POWER SUPPLY

Abstract

Provided is a wind turbine with an auxiliary power supply. The wind turbine includes a generator, a main converter and a transformer. The generator is connected with the main converter. The main converter is connected with the transformer. The transformer is connected with an electrical grid. Thus electrical power with a varying frequency, being produced by the generator, is converted into electrical power with a defined frequency by the main converter and the electrical power with the defined frequency is transformed and provided to the grid by the transformer while the transformation is done in accordance to grid code requirements. An auxiliary power supply, providing auxiliary power, is connected via an auxiliary converter with the transformer, thus the auxiliary power supply is decoupled from the transformer and from the grid by the auxiliary converter.

Claims

1. A wind turbine with an auxiliary power supply, the wind turbine comprising: a generator; a main converter; and a transformer; wherein the generator is connected with the main converter, the main converter is connected with the transformer, the transformer is connected with an electrical grid; wherein electrical power with a varying frequency is produced by the generator, and is converted into electrical power with a defined frequency by the main converter; the electrical power with the defined frequency being transformed and provided to the electrical grid by the transformer while the transformation is done in accordance to grid code requirements; wherein the auxiliary power supply, providing auxiliary power, is connected via an auxiliary converter with the transformer, and the auxiliary power supply is decoupled from the transformer and from the electrical grid by the auxiliary converter.

2. The wind turbine according to claim 1, wherein the auxiliary converter comprises a AC/DC converting part and a subsequent DC/AC converting part.

3. The wind turbine according to claim 1, wherein the auxiliary converter is a full-scale power converter.

4. The wind turbine according to claim 2, wherein an energy storage is connected with the DC-part of the auxiliary converter.

5. The wind turbine according to claim 1, wherein the auxiliary converter is connected, via a breaker, with the generator, and auxiliary power is provided to wind turbine components needed for basic functionalities of the wind turbine.

6. The wind turbine according to claim 1, wherein the generator is connected via a generator breaker with the main converter.

7. The wind turbine according to claim 1, wherein the main converter is connected via a main breaker with the transformer.

8. The wind turbine according to claim 7, wherein the main breaker is a high voltage main breaker.

9. The wind turbine according to claim 7, wherein the main converter is connected via the main breaker with the auxiliary converter.

10. The wind turbine according to claim 1, wherein a main reactor is connected between the main converter and a main breaker.

11. The wind turbine according to claim 1, wherein the transformer is connected via a breaker, which is a low voltage breaker, with the electrical grid.

12. The wind turbine according to claim 1, wherein the electrical grid is a wind farm internal grid or a power supply grid of a grid operator.

13. The turbine according to claim 7, wherein the main breaker is connected via an auxiliary breaker with the auxiliary converter.

14. The wind turbine according to claim 13, wherein an EMI-filter and/or an auxiliary transformer is connected between the auxiliary breaker and the auxiliary converter.

15. The wind turbine according to claim 1, wherein the auxiliary power unit comprises an uninterruptible power supply.

Description

BRIEF DESCRIPTION

[0042] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0043] FIG. 1 shows a first embodiment of a wind turbine according to the invention in a principle manner,

[0044] FIG. 2 shows a second embodiment of a wind turbine according to the invention in a principle manner,

[0045] FIG. 3 shows a third embodiment of a wind turbine according to the invention in a principle manner, and

[0046] FIG. 4 shows a wind turbine with an auxiliary power supply according to the prior art known as described above in the introduction of this description in a principle manner.

DETAILED DESCRIPTION

[0047] FIG. 1 shows a first embodiment of a wind turbine according to the invention.

[0048] For this figure reference is made to the equivalent components and functionalities a shown and described by help of FIG. 4.

[0049] According to the embodiments of the invention the auxiliary power supply APU is connected via an auxiliary converter AUXC1 with the auxiliary breaker AB.

[0050] Thus the auxiliary power supply APU is electrically decoupled from the auxiliary breaker AB and its subordinate components.

[0051] Due to this decoupling the main converter MCONV and the main reactor MR might provide an output voltage of 690 V (in this example, it might be other voltages referring to other manufacturers as well) with an extended allowed deviation of XX % and showing a frequency of 50 Hz or 60 Hz with an extended allowed deviation of +XX % as input for the transformer TR.

[0052] Thus the unwanted restrictions on voltage and frequency (as described above) can be avoided.

[0053] The auxiliary converter AUXC1 comprises an AC/DC converting part and a subsequent DC/AC converting part.

[0054] In a preferred configuration the auxiliary converter AUXC1 is a full-scale power converter.

[0055] The auxiliary converter AUXC1 is used to decouple the voltage and frequency dependence between the grid GR and the auxiliary power supply APU.

[0056] In a preferred configuration an EMF-filter EMF is arranged between the auxiliary breaker AB and the auxiliary converter AUXC1.

[0057] The EMF-filter EMF1 is used to filter harmonics on the grid GR before the auxiliary converter AUXC1.

[0058] In a preferred configuration an auxiliary transformer AUXT1 is arranged between the auxiliary breaker AB and the auxiliary converter AUXC1. Thus the auxiliary transformer AUXT1 is optional.

[0059] The auxiliary transformer AUXT1 can comprise these functionalities: step up or step down/isolated or auto.

[0060] The auxiliary transformer AUXT1 is used to step up or step down the voltage of the grid GR before the auxiliary converter AUXC1.

[0061] The generator G is preferably a Permanent Magnet Generator, PMG.

[0062] FIG. 2 shows a second embodiment of a wind turbine according to the invention.

[0063] For this figure reference is made to the equivalent components and functionalities a shown and described by help of FIG. 1 and by help of FIG. 4.

[0064] According to the embodiments of the invention the auxiliary power supply APU is connected via an auxiliary converter AUXC2 with the auxiliary breaker AB.

[0065] The auxiliary converter AUXC2 comprises an AC/DC converting part and a subsequent DC/AC converting part.

[0066] An energy storage ENS is connected with the DC-part of the auxiliary converter AUXC2.

[0067] The energy storage ENS can be any kind of batteries, super capacitors, etc.

[0068] In a preferred configuration the auxiliary converter AUXC2 is a full-scale power converter.

[0069] The energy storage ENS can be used to provide short time energy or power to the auxiliary converter AUXC2.

[0070] For a time limited period of time the uninterruptible power supply UPS can stop extracting power from the grid GR or from the configuration generator Gmain converter MCONV. Thus instead of doing so the power is extracted from the energy storage ENS and is supplied to the auxiliary power supply APU.

[0071] If the uninterruptible power supply UPS is equipped and connected with an active grid side it will be possible (for a time limited period) that the uninterruptible power supply UPS stops extracting power from the grid GR or from the configuration generator Gmain converter MCONV. Instead of this the power might be extracted from the energy storage ENS and might be supplied to the auxiliary power supply APU and to the generator G as well.

[0072] For example this might be used for an improved grid fault ride through, GFRT capability, for an improved inertia response, for an improved frequency control, for an improved reactive capability or for other ancillary services needed.

[0073] The auxiliary converter AUXC2 is acting like an Uninterruptable Power Supply, UPS and can operate with an active grid side or with a passive grid side.

[0074] FIG. 3 shows a third embodiment of a wind turbine according to the invention.

[0075] For this figure reference is made to the equivalent components and functionalities a shown and described by FIG. 2.

[0076] According to the embodiments of the invention the auxiliary power supply APU is connected via the auxiliary converter AUXC2 with the auxiliary breaker AB.

[0077] The auxiliary converter AUXC2 is additionally connected via a breaker BEMF-B with the generator G and with the generator breaker GB.

[0078] In case of a grid failure, a grid fault or in case of a grid disturbance it is possible to open the auxiliary breaker AB and the generator breaker GB.

[0079] Next the generator G is brought to a rotational speed, which is between 0 RPM and nominal RPM. Next the breaker B-EMF-B is closed and the auxiliary converter AUXC2 is supplied from the generator G directly.

[0080] Thus auxiliary power can be provided to wind turbine components and is used there to keep and to guarantee basic functionalities of the wind turbine. The auxiliary power might be used for enabling lubrication of bearings, to guarantee the functionality of warning lights, to heat dedicated components of the wind turbine, to ensure a dehumidification of internal power equipments (like converters), to ensure the communication between the wind turbine and controllers or to ensure communication between wind turbine components, etc.

[0081] Even a fast idling will be enabled. The fast idling refers to a method reducing tower-loads, which are caused by waves if the wind turbine is without grid connection. This gives a significant reduction in steel for the tower and foundation.

[0082] The advantage of this embodiment is that in case of short term or in case of a long term grid outage the wind turbine is able to produce its own auxiliary power needed and addressed above.

[0083] Although the invention has been illustrated and described in greater detail with reference to the preferred exemplary embodiment, the invention is not limited to the examples disclosed, and further variations can be inferred by a person skilled in the art, without departing from the scope of protection of the invention.

[0084] For the sake of clarity, it is to be understood that the use of a or an throughout this application does not exclude a plurality, and comprising does not exclude other steps or elements.