Wind park with multiple wind turbines

Patent metadata

Field	Value
Publication number	US-10903648-B2
Application number	US-201816496033-A
Country	US
Kind code	B2
Filing date	Mar 23, 2018
Priority date	Mar 24, 2017
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

A wind park for feeding power into a supply network at a connection point is provided. The wind park includes wind turbines for generating the power, a DC network for transmitting the power to the connection point, an inverter configured to transform electrical DC voltage into an AC voltage for feeding the power into the supply network, at least one DC-DC converter for feeding the power into the DC network. The DC-DC converter includes a switching device and a transformer with primary and secondary sides. The primary side is coupled to the at least one wind turbine via the switching device and the secondary side is coupled to the DC park network via at least one rectifier. The DC-DC converter is configured to apply a DC voltage of changing polarity to the primary side by the switching device to transform a DC voltage of the at least one wind turbine.

First claim

The invention claimed is:

1. A wind park for feeding electrical power into an electrical supply network at a network connection point, comprising:
at least two wind turbines for generating the electrical power;
a direct current (DC) park network for transmitting the electrical power from the at least two wind turbines to the network connection point;
an inverter arranged between the DC park network and the network connection point and configured to transform electrical DC voltage of the DC park network into an alternating current (AC) voltage for feeding the electrical power of the at least two wind turbines into the electrical supply network; and
at least one DC-DC converter for feeding the electrical power from at least one wind turbine of the at least two wind turbines into the DC park network, wherein:
the at least one DC-DC converter includes a switching device and a transformer with a primary side and a secondary side,
the primary side is coupled to the at least one wind turbine via the switching device,
the secondary side is coupled to the DC park network via at least one rectifier having a plurality of diodes, and
the DC-DC converter is configured to apply a DC voltage of changing polarity to the primary side of the transformer using the switching device thereby transforming a DC voltage of the at least one wind turbine from the primary side to the secondary side, and

wherein the transformer of the DC-DC converter is a step-up transformer configured to transform a lower voltage on the primary side into a higher voltage on the secondary side.

2. The wind park as claimed in claim 1 , wherein the at least one wind turbine provides the switching device with the DC voltage at a DC voltage output and the DC voltage is generated to be transformed from the primary side to the secondary side using the switching device.

3. The wind park as claimed in claim 1 , wherein the switching device includes two circuit breakers or at least four circuit breakers configured to apply the DC voltage as the DC voltage of the changing polarity to the primary side.

4. The wind park as claimed in claim 1 , wherein the transformer of the DC-DC converter is a high-frequency transformer configured to produce fewer electrical losses when transforming the DC voltage from the primary side to the secondary side in a case of high switching frequencies or large switching edges.

5. The wind park as claimed in claim 1 , wherein the transformer of the DC-DC converter is a DC isolating stage configured to perform DC isolation between the at least one wind turbine and the DC park network.

6. The wind park as claimed in claim 1 , wherein the transformer of the DC-DC converter is a high-voltage transformer configured to perform DC isolation between the at least one wind turbine and the DC park network, wherein the high-voltage transformer has a predefined transmission ratio.

7. The wind park as claimed in claim 1 , wherein the DC park network has a voltage for transmitting power that is greater than 6 kilovolt (kV).

8. The wind park as claimed in claim 1 , wherein the secondary side has at least two rectifiers configured to rectify the transformed DC voltage from the primary side to the secondary side into the DC voltage of the DC park network by full-wave rectifier circuit.

9. The wind park as claimed in claim 8 , wherein the full-wave rectifier circuit is a push-pull full-wave rectifier circuit or a bridge rectifier circuit.

10. The wind park as claimed in claim 1 , wherein the at least one rectifier includes high-voltage diodes.

11. The wind park as claimed in claim 1 , wherein the transformer has a center tap operative to perform push-pull full-wave rectification.

12. The wind park as claimed in claim 1 , wherein the transformed DC voltage from the primary side to the secondary side has a substantially square-wave profile.

13. The wind park as claimed in claim 1 , wherein the inverter includes, on a DC park network side, a discharging or grounding apparatus for achieving a zero-potential state in the DC park network or in a section of the DC park network, wherein the discharging or grounding apparatus has a chopper or a discharge resistor.

14. The wind park as claimed in claim 1 , wherein the DC park network includes at least one isolating switch for isolating a fault in a section of the DC park network, wherein the isolating switches is operative to connect or isolate sections of the DC park network to enable selective DC park network disconnection.

15. The wind park as claimed in claim 1 , wherein the DC park network is a ring network or a mesh network.

16. The wind park as claimed in claim 1 , wherein the primary side of the transformer is operative to be galvanically decoupled via the switching device, wherein electrical decoupling is performed by opening a switch arranged in the switching device to achieve complete electrical or galvanic decoupling between the at least one wind turbine and the DC park network.

17. The wind park as claimed in claim 1 , wherein the DC-DC converter is a forward converter or a resonant converter.

18. The wind park as claimed in claim 1 , wherein at least one electrical load or an energy store is arranged in the DC park network to electrically consume power inside the DC park network if the electrical supply network and the DC park network are isolated.

19. The wind park as claimed in claim 1 , comprising:
an isolating switch configured to automatically reclose or isolate a fault.

20. A method for controlling a wind park for feeding electrical power into an electrical supply network at a network connection point, comprising:
generating, by at least two wind turbines, the electrical power;
transmitting, by a DC park network, the electrical power from the at least two wind turbines to the network connection point;
transforming, by an inverter arranged between the DC park network and the network connection point, electrical DC voltage of the DC park network into an AC voltage for feeding the electrical power of the at least two wind turbines into the electrical supply network; and
feeding, by at least one DC-DC converter, the electrical power from at least one wind turbine of the at least two wind turbines into the DC park network, wherein:
the DC-DC converter has a switching device and a transformer with a primary side and a secondary side,
the primary side is coupled to the at least one wind turbine via the switching device,
the secondary side is coupled to the DC park network via at least one rectifier having a plurality of diodes, and
the DC-DC converter applies a DC voltage of changing polarity to the primary side of the transformer by the switching device, wherein a DC voltage of the at least one wind turbine is transformed from the primary side to the secondary side, and

wherein the transformer of the DC-DC converter is a step-up transformer configured to transform a lower voltage on the primary side into a higher voltage on the secondary side.

21. A wind park for feeding electrical power into an electrical supply network at a network connection point, comprising:
at least two wind turbines for generating the electrical power;
a direct current (DC) park network for transmitting the electrical power from the at least two wind turbines to the network connection point;
an inverter arranged between the DC park network and the network connection point and configured to transform electrical DC voltage of the DC park network into an alternating current (AC) voltage for feeding t

Assignees

• Wobben Properties Gmbh

Inventors

• Brombach Johannes
• Strafiel Christian

Classifications

• H02J2105/16

  being internal to power sources or power generation plants · CPC title

• H02J2101/28

  Wind energy · CPC title

• H02J4/25

  for transfer of electric power between AC and DC networks, e.g. for supplying the DC section within a load from an AC mains system · CPC title

• H02M3/33553 Primary

  with galvanic isolation between input and output of both the power stage and the feedback loop · CPC title

• H02J1/102 Primary

  being switching converters (H02J1/108, H02J1/12 take precedence) · CPC title