*** Withdrawn *** US 8188612 B2 Abstract A start-up method of a wind turbine generator includes a step of increasing a pitch angle of a wind turbine blade from a feather pitch angle to a fine pitch angle. The step of increasing the pitch angle of the wind turbine blade includes steps of: determining based on first to n-th pitch angles (n≧2) greater than the feather pitch angle and smaller than the fine pitch angle and first to n-th rotational speed conditions associated with the first to n-th pitch angles, respectively, whether a control target rotational speed, which is a wind turbine speed or generator speed, satisfies the i-th rotational speed condition when the pitch angle reaches the i-th rotational speed out of the first to n-th pitch angles, the first to n-th pitch angles and the first to n-th rotational speed conditions being stored in a storage unit; decreasing the pitch angle to the (i−1)-th pitch angle or the feather pitch angle in a case that the control target rotational speed does not satisfy the i-th rotational speed condition when the pitch angle reaches the i-th pitch angle; and increasing the pitch angle to the (i+1)-th pitch angle or the fine pitch angle in a case that the control target rotational speed satisfies the i-th rotational speed condition when the pitch angle reaches the i-th pitch angle.
Claims 1. A start-up method of a wind turbine generator, comprising:
a step of increasing a pitch angle of a wind turbine blade from a feather pitch angle to a fine pitch angle,
wherein the step of increasing said pitch angle includes using a controller to:
determine, based on first to n
^{th }pitch angles (n≧2) greater than said feather pitch angle and smaller than said fine pitch angle and first to n^{th }rotational speed conditions associated with said first to n^{th }pitch angles, respectively, whether a control target rotational speed, which is a wind turbine speed or generator speed, satisfies an i^{th }rotational speed condition out of said first to n^{th }rotational speed conditions when said pitch angle reaches an i^{th }rotational speed out of said first to n^{th }pitch angles, the first to n^{th }pitch angles and the first to nth n-th rotational speed conditions being stored in a storage unit of the controller, wherein n≧i≧1;decrease said pitch angle to an (i−1)
^{th }pitch angle or said feather pitch angle in a case that said control target rotational speed does not satisfy said i^{th }rotational speed condition when said pitch angle reaches the ith i-th pitch angle; andincrease said pitch angle to an (i+1)
^{th }pitch angle or said fine pitch angle in a case that said control target rotational speed satisfies said i^{th }rotational speed condition when said pitch angle reaches said i^{th }pitch angle.2. The start-up method according to
outputting an alarm in a case that said control target speed does not reach a predetermined interconnection speed when an elapsed time which is reckoned in response to a wind speed exceeding a start-up wind speed reaches a predetermined time.
3. A wind turbine generator, comprising:
a wind turbine rotor including a wind turbine blade having a variable pitch angle;
a generator coupled to said wind turbine rotor; and
a controller for controlling said pitch angle,
wherein said controller includes a storage unit storing first to n
^{th }pitch angles (n≧2) greater than a feather pitch angle and smaller than a fine pitch angle, and first to n^{th }rotational speed conditions associated with said first to n^{th }pitch angles, respectively,wherein said controller controls said pitch angle of said wind turbine blade to be increased from said feather pitch angle to said fine pitch angle,
in the control for increasing said pitch angle from said feather pitch angle to said fine pitch angle, said controller
determines whether a control target rotational speed, which is a wind turbine speed or a generator speed, satisfies an i
^{th }rotational speed condition out of said first to n^{th }rotational speed conditions when said pitch angle reaches an i^{th }pitch angle out of the first to n^{th }pitch angle,decreases said pitch angle to an (i−1)
^{th }pitch angle or said feather pitch angle if said control target rotational speed does not satisfy said i^{th }rotational speed condition when said pitch angle reaches said ith i-th pitch angle, andincreases said pitch angle to an (i+1)
^{th }pitch angle or said fine pitch angle if said control target rotational speed satisfies said i^{th }rotational speed condition when said pitch angle reaches said i^{th }pitch angle, wherein n≧i≧1.4. The wind turbine generator according to
Description The present application is National Phase of International Application Number PCT/JP2010/050435 filed Jan. 15, 2010, the disclosure of which is hereby incorporated by reference herein in its entirety. The present invention is related to a wind turbine generator, more particularly to optimization of the start-up procedure of a wind turbine generator. One issue that should be considered to start a wind turbine generator is to avoid undesired influence on the utility grid (for example, to reduction in the voltage of the utility grid) when the wind turbine generator is interconnected to the utility grid to be brought online. As a technique for preventing undesired influence on the utility grid, there is known a technique using a soft starter, for example. Such a technique is disclosed in, for example, Japanese Unexamined Patent Publication JP 2005-39924 A. One parameter that should be considered in starting the wind turbine generator is the generator speed (or the wind turbine speed). It is an effective approach for avoiding undesired influence on the utility grid to interconnect the wind turbine generator to the utility grid in a state in which the generator speed is controlled to an appropriate rotational speed (referred to as “interconnection speed”). It is necessary to set the pitch angle of the wind turbine blades to the fine pitch angle so as to raise the generator speed of the generator up to the interconnection speed. Here, a method is adopted in which the pitch angle is gradually increased from the feather pitch angle to the fine pitch angle, because of the necessity to gradually increase the wind turbine speed. One typical procedure is as follows: Referring to When a delay occurs to the follow-up of the rotational speed, however, such method may result in that the pitch angle is set to an excessive attack angle for the wind speed of the wind flowing into the wind turbine, causing stall of the wind turbine blades. A delay may occur to the follow-up of the rotational speed, for example, when the wind speed is reduced after the pitch angle starts being increased from the waiting speed or when the blades suffer from deterioration of the aerodynamic performance, weight increase or occurrence of unbalance, due to icing thereon. When the wind turbine blades are placed into the stall state, this disables the increase in the rotational speed, causing a start-up failure. In this case, it is required to start the start-up procedure over again, which disadvantageously causes a problem in the operation.
- Patent Document 1: JP 2005-39924 A
Therefore, an object of the present invention is to prevent a wind turbine blade from stalling in starting up a wind turbine generator and to thereby achieve a stable start-up of the wind turbine generator. In an aspect of the present invention, a start-up method of a wind turbine generator includes a step of increasing a pitch angle of a wind turbine blade from a feather pitch angle to a fine pitch angle. The step of increasing the pitch angle of the wind turbine blade includes steps of: determining based on first to n-th pitch angles (n≧2) greater than the feather pitch angle and smaller than the fine pitch angle and first to n-th rotational speed conditions associated with the first to n-th pitch angles, respectively, whether a control target rotational speed, which is a wind turbine speed or generator speed, satisfies the i-th rotational speed condition when the pitch angle reaches the i-th rotational speed out of the first to n-th pitch angles, the first to n-th pitch angles and the first to n-th rotational speed conditions being stored in a storage unit; decreasing the pitch angle to the (i−1)-th pitch angle or the feather pitch angle in a case that the control target rotational speed does not satisfy the i-th rotational speed condition when the pitch angle reaches the i-th pitch angle; and increasing the pitch angle to the (i+1)-th pitch angle or the fine pitch angle in a case that the control target rotational speed satisfies the i-th rotational speed condition when the pitch angle reaches the i-th pitch angle. In the above-described procedure of the start-up method of the wind turbine generator, the pitch angle is decreased when the wind turbine/generator speed is not sufficiently increased in the process of increasing the pitch angel of the wind turbine blade up to the fine pitch angle, and this prevents the wind turbine blade from stalling to achieve a stable start-up of the wind turbine generator. In another aspect of the present invention, a wind turbine generator is provided with a wind turbine rotor including a wind turbine blade having a variable pitch angle; a generator coupled to the wind turbine rotor; and a controller for controlling the pitch angle. The controller includes a storage unit storing first to n-th pitch angles (n≧2) greater than a feather pitch angle and smaller than a fine pitch angle and first to n-th rotational speed conditions associated with the first to n-th pitch angles, respectively. The controller controls the pitch angle of the wind turbine blade to be increased from the feather pitch angle to the fine pitch angle. In the control for increasing the pitch angle from the feather pitch angle to the fine pitch angle, the controller determines whether a control target rotational speed, which is a wind turbine speed or a generator speed, satisfies the i-th rotational speed condition when the pitch angle reaches the i-th pitch angle out of the first to n-th pitch angle. The controller decreases the pitch angle to the (i−1)-th pitch angle or the feather pitch angle if the control target rotational speed does not satisfy the i-th rotational speed condition when the pitch angle reaches the i-th pitch angle, and increases the pitch angle to the (i+1)-th pitch angle or the fine pitch angle if the control target rotational speed satisfies the i-th rotational speed condition when the pitch angle reaches the i-th pitch angle. In the wind turbine generator thus constructed, the pitch angle is decreased when the wind turbine/generator speed is not sufficiently increased in the process of increasing the pitch angle of the wind turbine blade up to the fine pitch angle, and this prevents the wind turbine blade from stalling to achieve a stable start-up of the wind turbine generator. The present invention prevents the wind turbine blade from stalling in starting up the wind turbine generator, and thereby achieves a stable start-up of the wind turbine generator. The pitch controller In the following, a description is given of the start-up procedure of the wind turbine generator First, an outline of the start-up procedure of the wind turbine generator In the following, a specific example of the start-up procedure of the wind turbine generator Initially, the wind turbine rotor When the pitch angle θ of the wind turbine blades When the pitch angle θ of the wind turbine blades When the pitch angle θ of the wind turbine blades When the pitch angle θ of the wind turbine blades Subsequently, the procedures of increasing the pitch angle θ step by step are similarly repeated until the pitch angle θ reaches the fine pitch angle θfine. When the generator speed N reaches the interconnection speed Nin in a state in which the pitch angle θ of the wind turbine blades In the above-described start-up procedure of the wind turbine generator In the start-up procedure of the wind turbine generator More specifically, the start-up of the wind turbine generator If the generator speed N does not reach the interconnection speed Nin even when the elapsed time from starting the wind turbine generator The reckoning time from which the elapsed time is reckoned may be defined variously. For example, the reckoning time may be defined as the time when the wind turbine rotor Although various embodiments of the present invention are specifically described, the present invention should not be interpreted to be limited to the above-stated embodiments. For example, the rotational speed of the wind turbine rotor Legal Events
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