Variable speed distributed drive train wind turbine system

• US 20050012339A1
• Filed: 02/04/2004
• Published: 01/20/2005
• Est. Priority Date: 05/07/2003
• Status: Active Grant

• Current Assignee: Clipper Windpower, LLC
• Original Assignee: Clipper Windpower Technology, Inc.
• Inventors: Erdman, William, Cousineau, Kevin L., Mikhail, Amir S., Holley, William, Howes, Lawrence H.
• Granted Patent: US 7,042,110 B2
• Time in Patent Office: Days
• US Class Current: 290/44
• CPC Class Codes: F03D 15/10 using gearing not limited to rotary motion, e.g. with oscillating or reciprocating members
• CPC Class Codes: F03D 7/0224 Adjusting blade pitch
• CPC Class Codes: F03D 7/0272 by measures acting on the electrical generator
• CPC Class Codes: F03D 7/0276 controlling rotor speed, e.g. variable speed
• CPC Class Codes: F03D 7/028 controlling wind motor output power
• CPC Class Codes: F03D 7/0284 in relation to the state of the electric grid
• CPC Class Codes: F03D 7/042 by means of an electrical or electronic controller
• CPC Class Codes: F03D 7/048 controlling wind farms
• CPC Class Codes: F03D 9/25 the apparatus being an electrical generator F03D9/22 takes precedence
• CPC Class Codes: F03D 9/255 connected to electrical distribution networks; Arrangements therefor
• CPC Class Codes: F03D 9/257 the wind motor being part of a wind farm
• CPC Class Codes: F05B 2210/16 Air or water being indistinctly used as working fluid, i.e. the machine can work equally with air or water without any modification
• CPC Class Codes: F05B 2270/1016 in variable speed operation
• CPC Class Codes: F05B 2270/1032 Torque
• CPC Class Codes: F05B 2270/337 Electrical grid status parameters, e.g. voltage, frequency or power demand
• CPC Class Codes: H02J 2300/20 The dispersed energy generation being of renewable origin
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 2300/28 The renewable source being wind energy
• CPC Class Codes: H02J 3/0012 Contingency detection
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/40 : Synchronising a generator for connection to a network or to another generator
• CPC Class Codes: H02P 2101/10 : for water-driven turbines
• CPC Class Codes: H02P 2101/15 : for wind-driven turbines
• CPC Class Codes: H02P 5/747 : mechanically coupled by gearing
• CPC Class Codes: H02P 9/02 : Details of the control
• CPC Class Codes: H02P 9/04 : Control effected upon non-electric prime mover and dependent upon electric output value of the generator
• CPC Class Codes: H02P 9/10 : Control effected upon generator excitation circuit to reduce harmful effects of overloads or transients, e.g. sudden application of load, sudden removal of load, sudden change of load
• CPC Class Codes: H02P 9/102 : for limiting effects of transients
• CPC Class Codes: H02P 9/105 : for increasing the stability
• CPC Class Codes: H02P 9/107 : for limiting effects of overloads
• CPC Class Codes: Y02E 10/56 : Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 10/72 : Wind turbines with rotation axis in wind direction
• CPC Class Codes: Y02E 10/76 : Power conversion electric or electronic aspects

Abstract

A variable speed wind turbine employing a rotor connected to a multiplicity of synchronous generators with wound field or permanent magnet rotors. A passive rectifier and an inverter are used for power transfer back to the grid. A Turbine Control Unit (TCU) commands a required generator torque based on rotor speed and power output of the turbine inverters. Torque is controlled by regulating the DC current by control of the inverter. A main-shaft-damping filter is provided by measurement of the DC bus voltage. In high winds the turbine remains at a constant average output power through a constant torque command and a varying pitch command to a rotor pitch servo system. A set point is fixed at the inverter output such that output VAR load is minimized running the turbine at very nearly unity power factor. Dynamic VAR and power factor control is provided by a separate VAR apparatus.

Claims

1. An electric power-generating device comprising:

a main input shaft turned by a source of energy;

a synchronous generator operatively connected to said main input shaft, an output of said synchronous generator being AC electrical power;

a passive rectifier connected to said output of said synchronous generator, an output of said passive rectifier being DC electrical power; and

,

an inverter connected to said output of said passive rectifier, an output of said inverter being AC electrical power.

2. The electric power-generating device of claim 1 wherein said device includes a plurality of synchronous generators operatively connected to said main input shaft.

3. The electric power-generating device of claim 2 further comprising a controller that brings each generator of said plurality of synchronous generators online sequentially in the event of low energy conditions of said source of energy to improve system efficiency at low power.

4. The electric power-generating device of claim 3 wherein said controller alternates the sequence in which said controller shifts the order in which said generators are brought online such that each generator receives substantially similar utilization.

5. The electric power-generating device of claim 1 wherein electric power-generating device is a wind turbine that includes said generator, and said passive rectifier, said wind turbine being located at the top of a tower and wherein said inverter is located at the bottom of said tower.

6. The electric power-generating device of claim 5 wherein a set of power cables conduct electrical power from the top of said tower to the bottom of said tower and wherein said power cables conduct DC electrical power.

7. The electric power-generating device of claim 6 wherein said set of power cables consist of two cables per generator.

8. The electric power-generating device of claim 1 wherein said passive rectifier comprises a plurality of diodes that convert AC electrical power into DC electrical power.

9. The electric power-generating device of claim 8 wherein said generator is a three-phase synchronous generator and wherein said passive rectifier comprises six diodes.

10. The electric power-generating device of claim 1 further comprising a controller that controls generator torque by regulating the current in said DC electrical power.

11. The electric power-generating device of claim 10 wherein the voltage of said DC electrical power is measured and used as an input to said controller.

12. The electric power-generating device of claim 11 further comprising a band pass filter for said voltage measurement that is tuned to measure vibrations in mechanical portions of said electric power-generating device at a predetermined resonant frequency and wherein said controller provides a generator torque signal that cancels and dampens vibrations.

13. The electric power-generating device of claim 1 further comprising a controller that measures vibrations in mechanical portions of said electric power-generating device and controls generator torque to actively dampen said vibrations.

14. The electric power-generating device of claim 13 wherein said controller measures said vibrations by measuring the voltage of said DC electrical power.

15. The electric power-generating device of claim 14 further comprising a band pass filter in said controller to filter said DC electrical power to a predetermined frequency that corresponds to a mechanical resonance in said mechanical portions of said electric power-generating device.

16. A fluid-flow turbine comprising:

a blade for converting fluid-flow power into mechanical power;

a plurality of generators operatively connected to said blade for converting said mechanical power into AC electrical power;

a passive rectifier electrically connected to each of said generators for converting said AC electrical power into DC electrical power; and

an inverter electrically connected to each of said passive rectifiers to convert said DC electrical power into AC electrical power.

17. The electric power-generating device of claim 16 further comprising a controller for bringing each generator online sequentially in low fluid-flow conditions to improve system efficiency at low power.

18. The electric power-generating device of claim 17 wherein said controller alternates the sequence in which said controller shifts the order in which said generators are brought online such that each generator receives substantially similar utilization.

19. A fluid-flow farm comprising:

a plurality of fluid-flow turbines each of which converts fluid-flow power into AC electrical power at substantially unity power factor;

an electrical collection system that electrically connects each of said fluid-flow turbines to a substation wherein said electrical collection system is sized for operation of said fluid-flow turbines at substantially unity power factor; and

a dynamically adjustable power factor controller at said substation for adjusting the power factor of the aggregate output of said fluid-flow farm.

20. A fluid-flow farm comprising:

a plurality of fluid-flow turbines each of which converts fluid-flow power into AC electrical power at substantially unity power factor;

each one of said fluid-flow turbines comprising a blade which converts fluid-flow power into mechanical power, a synchronous generator operatively connected to said blade to convert said mechanical power into AC electrical power, a passive rectifier to convert said AC electrical power into DC electrical power, and an inverter to convert said DC electrical power into AC electrical power;

an electrical collection system that electrically connects each of said fluid-flow turbines to a substation wherein said electrical collection system is sized for operation of said fluid-flow turbines at substantially unity power factor; and

,

a dynamically adjustable power factor controller at said substation for adjusting the power factor of the aggregate output of said fluid-flow farm.

21. An apparatus for generating electric power comprising:

first means for converting fluid-flow power into mechanical power;

a plurality of generators connected to said first means for converting said mechanical power into AC electrical power;

rectifying means connected to said plurality of generators for rectifying outputs of said generators to thereby convert said AC electrical power of said generators into DC electrical power; and

inverting means connected to said rectifying means for inverting said DC electrical power to thereby convert said DC electrical power to AC electrical power.

22. The apparatus of claim 21 further comprising:

means for bringing each of said generators online sequentially in low fluid-flow conditions to improve system efficiency at low power.

23. The apparatus of claim 22 wherein the order in which said generators are brought online is such that each generator receives substantially similar utilization.

24. An apparatus for generating electric power comprising:

a plurality of fluid-flow turbines, each of which converts fluid-flow power into AC electrical power at substantially unity power factor;

an electrical collection system for electrically connecting each of said fluid-flow turbines to a substation wherein said electrical collection system is sized for operation of said fluid-flow turbines at substantially unity power factor; and

means at said substation for dynamically adjusting the power factor of the aggregate output of said plurality of fluid-flow turbines.

25. A apparatus for generating electric power comprising:

a plurality of fluid-flow turbines, each of which utilizing a blade to drive synchronous generators that convert fluid-flow power into AC electrical power at substantially unity power factor;

converting means associated with each turbine for converting said AC electrical power of said synchronous generators into DC electrical power;

means for inverting said DC electrical power of each said synchronous generators of a turbine to thereby convert said DC electrical power to AC electrical power;

an electrical collection system for electrically connecting each of said fluid-flow turbines to a substation wherein said electrical collection system is sized for operation of said fluid-flow turbines at substantially unity power factor; and

,

means for dynamically adjusting the power factor of the aggregate output of said plurality of fluid-flow turbines at said substation.

26. The apparatus of claim 25 further comprising:

a number of towers, one for each of said plurality of turbines;

each turbine and an associated converting means being located on top of one of said towers; and

,

said means for inverting being located at a bottom of said tower.

27. The apparatus of claim 26 further comprising:

means for conducting DC electrical power electrical power from said converting means at said top of said tower to said inverting means at said bottom of said tower.

28. A method of generating electric power comprising steps of:

A. converting fluid-flow power into mechanical power;

B. utilizing a plurality of generators to convert said mechanical power into AC electrical power;

C. rectifying outputs of said generators to thereby convert said AC electrical power of said generators into DC electrical power; and

D. inverting said DC electrical power to thereby convert said. DC electrical power to AC electrical power.

29. The method of claim 28 further comprising a step of:

E. bringing each of said generators online sequentially in low fluid-flow conditions to improve system efficiency at low power.

30. The method of claim 29 wherein in said step E the order in which said generators are brought online is such that each generator receives substantially similar utilization.

31. A method of generating electric power comprising steps of:

A. providing a plurality of fluid-flow turbines, each of which converts fluid-flow power into AC electrical power at substantially unity power factor;

B. electrically connecting each of said fluid-flow turbines via an electrical collection system to a substation wherein said electrical collection system is sized for operation of said fluid-flow turbines at substantially unity power factor; and

C. dynamically adjusting the power factor of the aggregate output of said plurality of fluid-flow turbines at said substation.

32. A method of generating electric power comprising steps of:

A. providing a plurality of fluid-flow turbines, each of which utilizing a blade to drive synchronous generators that convert fluid-flow power into AC electrical power at substantially unity power factor;

B. rectifying outputs of each said synchronous generators of a turbine to thereby convert said AC electrical power of said synchronous generators into DC electrical power;

C. inverting said DC electrical power of each said synchronous generators of a turbine to thereby convert said DC electrical power to AC electrical power;

D. electrically connecting each of said fluid-flow turbines via an electrical collection system to a substation wherein said electrical collection system is sized for operation of said fluid-flow turbines at substantially unity power factor; and

,

E. dynamically adjusting the power factor of the aggregate output of said plurality of fluid-flow turbines at said substation.

33. The method of claim 32 wherein:

said step A of providing a plurality of fluid-flow turbines includes the step of providing a plurality of towers with each one of said turbines on top of one of said towers;

said step B of rectifying outputs of each said generators is performed at said top of said one tower; and

,

said step C of inverting said DC electrical power of each said synchronous generators of a turbine to thereby convert said DC electrical power to AC electrical power is performed at a bottom of said one tower.

34. The method of claim 33 further comprising a step of:

F. conducting DC electrical power electrical power from said top of one tower to said bottom of said one tower prior to said step C of inverting said DC electrical power of each said synchronous generators of a turbine.