Wind turbine generator system

• US 7,205,676 B2
• Filed: 06/27/2006
• Issued: 04/17/2007
• Est. Priority Date: 01/08/2004
• Status: Active Grant

• Current Assignee: Hitachi Industrial Products, Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Ichinose, Masaya, Futami, Motoo, Sakai, Hiromitsu
• Primary Examiner(s): Ponomarenko; Nicholas
• Application Number:
  US11/475,416
• Publication Number:
  US 20060244265A1
• Time in Patent Office: 294 Days
• Field of Search: 290/43, 290/44, 290/54, 290/55, 322/24, 322/25, 322/29, 322/37
• US Class Current: 290/44
• CPC Class Codes: F03D 7/026 for starting-up
• CPC Class Codes: F03D 9/255 connected to electrical distribution networks; Arrangements therefor
• CPC Class Codes: F05B 2270/337 Electrical grid status parameters, e.g. voltage, frequency or power demand
• CPC Class Codes: H02P 2101/15 for wind-driven turbines
• CPC Class Codes: H02P 9/007 Control circuits for doubly fed generators
• 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: Y02E 10/72 Wind turbines with rotation axis in wind direction

Abstract

To shorten a startup interval to reach a synchronizing condition, a phase difference and an amplitude difference between the grid voltage and the stator voltage of one phase of a winding are obtained. The difference in amplitude is decreased prior to or in parallel to synchronizing the stator voltage with the grid voltage. The calculated compensation phase compensation value is used as an initial value for synchronizing at the next synchronizing operation.

Claims

1. A wind turbine generator system including switching means arranged on a stator side of a doubly fed generator for linkage with a grid and a converter for exciting a secondary winding of the doubly fed generator, a rotor of the doubly fed generator coupled to a wind turbine for generating electric power, comprising:

first detection means for detecting a stator voltage at the switching means on the stator side of the doubly fed generator;

second detection means for detecting a grid voltage at the switching means on the side of the grid;

third detection means for detecting a rotation phase of the doubly fed generator;

equalizing means for equalizing, when the switch is open, the stator voltage generated by excitation on the secondary side with the grid voltage; and

controlling means for decreasing a difference in phase between the grid voltage and the stator side voltage with the converter when the switch is open after the equalizing means equalizes the stator voltage generated by excitation on the secondary side with the grid voltage.

2. The wind turbine generator system as claimed in claim 1, further comprising means for previously equalizing the stator voltage with the grid voltage in amplitude and then synchronizing the stator voltage with the grid voltage in phase.