Speed management of a wind turbine when switching electrical configurations

Patent metadata

Field	Value
Publication number	US-2016208781-A1
Application number	US-201414916618-A
Country	US
Kind code	A1
Filing date	Sep 3, 2014
Priority date	Sep 5, 2013
Publication date	Jul 21, 2016
Grant date	—

Abstract

To efficiently nm a wind turbine in varying wind speeds, the wind turbine may be configured to switch between two different electrical configurations that offer different efficiencies depending on wind speed. For example, a star configuration may be preferred during low wind speeds while a delta configuration is preferred for high wind speeds. Before switching, the power output by the turbine's generator may be driven to zero. Doing so, however, removes load from the rotor blades which cause the rotor speed to increase. Instead, the rotor speed may be controlled such that the speed stays at or above the speed of the rotor immediately before the generator power is ramped down. Maintaining rotor speed at or slightly above the current speed while switching between electrical configurations may mitigate the torque change experienced by the turbine and reduce the likelihood of structural failure.

First claim

We claim:

1 . A controller for a wind turbine, the controller comprising control logic configured to:
upon determining to switch between electrical configurations when operating at a pre-switch rotor speed, decrease an output power produced by a generator in the wind turbine; while decreasing the output power, adjust a parameter associated with a rotor of the wind turbine to maintain the speed of the rotor at or above at least one of the pre-switch rotor speed and a desired post-switch rotor speed; upon determining that the output power reaches a predefined power value, switch between a first electrical configuration associated with the generator to a second electrical configuration; after switching to the second electrical configuration, increase the output power produced by the generator in the wind turbine; and while increasing the output power, adjust the parameter associated with the rotor to maintain the speed of the rotor at or above at least one of the pre-switch rotor speed and the desired post-switch rotor speed.

2 . The controller of claim 1 , wherein determining to switch from the first electrical configuration to the second electrical configuration comprises determining that the output power of the generator satisfies a power threshold for a predefined period of time.

3 . The controller of claim 2 , wherein determining to switch from the first electrical configuration to the second electrical configuration comprises evaluating the output power of the generator to a plurality of different power thresholds associated with respective power values, each power threshold is associated with a different time constraint that determines whether to switch from the first electrical configuration to the second electrical configuration.

4 . The controller of claim 1 , wherein the first electrical configuration is a delta configuration and the second electrical configuration is a star configuration.

5 . The controller of claim 1 , wherein the control logic is configured to:
increase the output power of the generator to a desired output power value corresponding to the second electrical configuration, wherein, when the generator outputs the desired output power value, the control logic operates the wind turbine at the desired post-switch rotor speed.

6 . The controller of claim 1 , wherein adjusting the parameter associated with the rotor to maintain the speed of the rotor at or above the current rotor speed comprises at least one of (i) changing a pitch of a blade in the rotor to compensate for a reduced load associated with the generator and (ii) braking the rotor.

7 . The controller of claim 1 , wherein the control logic is configured to:
track the number of switches between the first and second electrical configurations; compare the number of switches to a switching budget; and upon determining the number of switches exceed the switching budget, adjust at least one switching criteria to reduce a switching rate associated with the wind turbine.

8 . A wind turbine, comprising:
a generator; a rotor coupled to the generator; and a controller configured to:
upon determining to switch between electrical configurations when operating at a pre-switch rotor speed, decrease an output power produced by the generator,
while decreasing the output power, adjust a parameter associated with the rotor to maintain the speed of the rotor at or above at least one of the pre-switch rotor speed and a desired post-switch rotor speed,
upon determining that the output power reaches a predefined power value, switch between a first electrical configuration associated with the generator to a second electrical configuration,
after switching to the second electrical configuration, increase the output power produced by the generator, and
while increasing the output power, adjust the parameter associated with the rotor to maintain the speed of the rotor at or above at least one of the pre-switch rotor speed and the desired post-switch rotor speed.

9 . The wind turbine of claim 8 , wherein determining to switch from the first electrical configuration to the second electrical configuration comprises determining that the output power of the generator satisfies a power threshold for a predefined period of time.

10 . The wind turbine of claim 9 , wherein determining to switch from the first electrical configuration to the second electrical configuration comprises evaluating the output power of the generator to a plurality of different power thresholds that define a plurality of different power ranges, each power range is associated with a different time constraint that determines whether to switch from the first electrical configuration to the second electrical configuration.

11 . The wind turbine of claim 8 , wherein the first electrical configuration is a delta configuration and the second electrical configuration is a star configuration.

12 . The wind turbine of claim 8 , wherein the control logic is configured to:
increase the output power of the generator to a desired output power value corresponding to the second electrical configuration, wherein, when the generator outputs the desired output power value, the controller operates the wind turbine at the desired post-switch rotor speed.

13 . The wind turbine of claim 8 , wherein adjusting the parameter associated with the rotor to maintain the speed of the rotor at or above the current rotor speed comprises at least one of (i) changing a pitch of a blade in the rotor to compensate for a reduced load associated with the generator and (ii) braking the rotor.

14 . The wind turbine of claim 8 , wherein the controller is configured to:
track the number of switches between the first and second electrical configurations; compare the number of switches to a switching budget; and upon determining the number of switches exceed the switching budget, adjust at least one switching criteria to reduce a switching rate associated with the wind turbine.

15 . A method for controlling a wind turbine, the method comprising:
upon determining to switch between electrical configurations when operating at a pre-switch rotor speed, decreasing an output power produced by a generator in the wind turbine; while decreasing the output power, adjusting, by operation of one or more computer processors, a parameter associated with a rotor of the wind turbine to maintain the speed of the rotor at or above at least one of the pre-switch rotor speed and a desired post-switch rotor speed; upon determining that the output power reaches a predefined power value, switching between a first electrical configuration associated with the generator to a second electrical configuration; after switching to the second electrical configuration, increasing the output power produced by the generator in the wind turbine; and while increasing the output power, adjusting the parameter associated with the rotor to maintain the speed of the rotor at or above at least one of the pre-switch rotor speed and the desired post-switch rotor speed.

16 . The method of claim 15 , wherein determining to switch from the first electrical configuration to the second electrical configuration comprises determining that the output power of the generator satisfies a power threshold for a predefined period of time.

17 . The method of claim 16 , wherein determining to switch from the first electrical configuration to the second electrical configuration comprises evaluating the output power of the generator to a plurality of different power thresholds that define a plurali

Assignees

• Vestas Wind Sys As

Inventors

• Kjær Martin Ansbjerg
• Koldkjaer Peter
• Knudsen Mølgaard Hviid
• Soleimanzadeh Maryam
• Sørensen Martin Møller
• Zaib Ali
• Singh Arvishwa Kumar
• Christensen Poul Brandt
• Jensen Michael Houlind

Classifications

• F03D7/028 Primary

  controlling wind motor output power · CPC title

• G05F1/66

  Regulating electric power · CPC title

• F03D9/002

  Mechanical Engineering · mapped topic

• F03D7/047

  characterised by the controller architecture, e.g. multiple processors or data communications · CPC title

• F03D1/06

  Rotors · CPC title