CN109139372B - 一种基于独立变桨的风电机组控制和制动方法 - Google Patents
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Abstract
本发明属于风电技术领域,涉及一种基于独立变桨的风电机组控制和制动方法。在风电机组采取变桨距制动时,通过安装在每个叶片上的桨距调节器来增大每个叶片的桨距角;根据每个叶片桨距角的变化速率分别调节各个叶片的桨距角;每个叶片根部安装应变传感器,在轮毂内缘安装用于测量叶片桨距的传感器,在机舱内安装桨距调节器和控制器;通过位于三个叶片根部的应变传感器测量得到各自对应拉伸应力大小,并计算出每个叶片桨距角的响应变化速率;在不同时刻,通过桨距调节器增大每个叶片的桨距角,直至达到最大角度90度。本发明方法减少了风机在制动时由于不平衡载荷带来的冲击载荷,提高风机主轴和轴承的寿命。
Description
技术领域
本发明属于风电技术领域,涉及一种基于独立变桨的风电机组控制和制动方法。
背景技术
世界上的风机,根据其叶轮主轴的方向,可以分为水平轴和垂直轴式。目前已经建成的陆上或海上风电场,都由水平轴式风机组成。水平轴式风机,根据其叶片控制方式,又可大致分为失速型和变桨距两种。失速型风机,在运行时具有固定的桨距和转速,型式简单,多应用在早期的千瓦级风机上。大型兆瓦级别的风机,为了提高发电效率,具有变桨距和变速的特性。
水平轴风机的结构设计,需要满足一系列的工况下的极限和疲劳载荷。国际设计规范中包含的工况有正常运行工况,停机工况和制动工况等。对于变桨距风机,制动工况通常意味着风机三个桨叶在短时间内以相同的速率增加到最大桨距角(90度)。在此过程中,由于叶片的桨距角突然增大,叶轮所受的气动力扭矩方向反转,使叶轮在短时间内停止转动。
风机的制动原因,一方面可能由于风速过大,需要停止运行来避免结构劳损,另一方面可能是风机的关键部位发生故障,需要停止运行来检修。在上述的制动过程中,由于叶片桨距角的迅速增大,往往会对风机主轴造成较大的冲击载荷。此外,由于湍流风的存在,叶片盘面内三个风机叶片的局部进流风速并不相等,从而导致叶片的受力不均,三个叶片根部的弯矩也不平衡。这一现象常导致风机齿轮箱主轴轴承的结构疲劳劳损,不利于控制风电运营的维护成本。
发明内容
本发明目的在于提出一种减少风机制动过程中叶片根部不平衡载荷的方法,从而提高风机运行的可靠性,降低维护成本。
一种基于独立变桨的风电机组制动方法,步骤如下:在风电机组采取变桨距制动时,通过安装在每个叶片上的桨距调节器来增大每个叶片的桨距角;由于风电机组是独立变桨系统,每个叶片桨距角的变化速率不同;根据每个叶片桨距角的变化速率分别调节各个叶片的桨距角;
每个叶片根部安装应变传感器,在轮毂内缘安装用于测量叶片桨距的传感器,在机舱内安装桨距调节器和控制器;
通过位于三个叶片根部的应变传感器测量得到各自对应拉伸应力大小,并计算出每个叶片桨距角的响应变化速率;
对于第k个叶片,其桨距角的响应变化速率和拉伸应力的关系:
其中,为叶片k的桨距角的响应变化速率,k=1、2、3;σ1,σ2,σ3分别为在某时刻叶片1、2、3根部的拉伸应力;μ为系数,通过数值模拟确定大小;从关系式看出,当叶片k的拉伸应力σk过大时,应维持较小的桨距角响应变化速率,反之则采用较大的桨距角响应变化速率,但桨距角的响应变化速率不可超过桨距调节系统的限制在不同时刻,通过桨距调节器增大每个叶片的桨距角,直至达到最大角度90度;当叶轮转速小于1rpm,风机制动完成,叶片桨距角停止变化。
所述的风机是水平轴变桨距风力发电机、陆上或海上风机。
本发明的有益效果:
(1)该装置组成部件,包括应力应变片,传感器,桨距调节系统均为成熟的工业产品,容易实施。
(2)减少了风机在制动时由于不平衡载荷带来的冲击载荷,提高风机主轴和轴承的寿命。
(3)提高风机可靠性的同时降低了维护成本。
附图说明
图1是一个陆上三叶片水平轴风机的示意图。
图2(a)是位于风机顶部的叶片在制动前的桨距位置示意图。
图2(b)是位于风机顶部的叶片在制动后的桨距位置示意图。
图3(a)是常规制动,风机桨距角在制动时的变化示意图。
图3(b)是本发明方法独立变桨制动,风机桨距角在制动时的变化示意图。
图4(a)是常规制动,风机盘面内的不平衡载荷弯矩在制动过程中的变化示意图。
图4(b)是本发明方法独立变桨制动,风机盘面内的不平衡载荷弯矩在制动过程中的变化示意图。
图5是适用于风机制动过程的独立变桨的控制框图。
图6是本发明方法的制动流程图。
图中:1叶片;2应变传感器;3海床;4叶片剖面;5风轮平面。
具体实施方式
以下结合附图和技术方案,进一步说明本发明的具体实施方式。
一种基于独立变桨的风电机组制动方法,步骤如下:在风电机组采取变桨距制动时,通过安装在每个叶片上的桨距调节器来增大每个叶片的桨距角;由于风电机组是独立变桨系统,每个叶片桨距角的变化速率不同;根据每个叶片桨距角的变化速率分别调节各个叶片的桨距角;
每个叶片根部安装应变传感器,在轮毂内缘安装用于测量叶片桨距的传感器,在机舱内安装桨距调节器和控制器;
通过位于三个叶片根部的应变传感器测量得到各自对应拉伸应力大小,并计算出每个叶片桨距角的响应变化速率;
对于第k个叶片,其桨距角的响应变化速率和拉伸应力的关系:
其中,为叶片k的桨距角的响应变化速率,k=1、2、3;σ1,σ2,σ3分别为在某时刻叶片1、2、3根部的拉伸应力;μ为系数,通过数值模拟确定大小;从关系式看出,当叶片k的拉伸应力σk过大时,应维持较小的桨距角响应变化速率,反之则采用较大的桨距角响应变化速率,但桨距角的响应变化速率不可超过桨距调节系统的限制在不同时刻,通过桨距调节器增大每个叶片的桨距角,直至达到最大角度90度;当叶轮转速小于1rpm,风机制动完成,叶片桨距角停止变化。
图1所示的风机属于6MW级别,机舱长度为10米,重量360顿,机舱水平高于地平面100米。在每个叶片的根部连接有应变传感器,用以测量拉应力,并计算叶片在制动时受到的弯矩载荷。
图2所示是某个叶片在制动初始和结束时的位置。叶片初始桨距角θ1=15度,在桨距调节器的作用下,角度不断变大直至θ2=90。在这一过程中,作用在叶轮上的空气扭矩反转,使叶轮慢慢停止。
图3所示三个叶片在制动过程中的桨距角变化。左图中,采用的是常规的制动方式,三个叶片为统一变桨控制,桨距角在t0时刻以相同速率增加到90度。在t1时刻,制动已经完成。图右所示的是采用独立变桨制动的效果。由于三个叶片采用独立控制,其变化路径并不相同,三个叶片分别在t1,t2,t3时刻达到最大角度。
图4所示是对风机主轴起到破坏作用的不平衡载荷变化示意。当采用常规制动时(左图),由于三个叶片上受到空气载荷的不均匀,弯矩在制动发生后保持较高水平,直至制动结束,当采用独立变桨制动时,由于通过调整三个叶片的桨距角,可使三个叶片受力均匀,从而保持较低的不平衡载荷。
图5所示是该独立变桨控制系统的框图。如图所示,该系统的关键之一是根据叶根应变传感器的测量值计算出每个叶片的桨距角变化率,并通过每个叶片的独立桨距调节器来调整叶片角度变化。
图6所示的是该独立变桨控制系统在风机制动过程中的系统工作流程图。随着风速变化和叶片转速的变化,单个叶片所受到的空气载荷不同,根据叶片根部应变片采集到的数据信号来计算下一时刻的桨距变化率,变桨驱动器不断调节桨距角,直至叶轮速度降低到满足要求。
Claims (1)
1.一种基于独立变桨的风电机组制动方法,在风电机组采取变桨距制动时,通过安装在每个叶片上的桨距调节器来增大每个叶片的桨距角;由于风电机组是独立变桨系统,每个叶片桨距角的变化速率不同;根据每个叶片桨距角的变化速率分别调节各个叶片的桨距角;其特征在于,步骤如下:
每个叶片根部安装应变传感器,在轮毂内缘安装用于测量叶片桨距的传感器,在机舱内安装桨距调节器和控制器;
通过位于三个叶片根部的应变传感器测量得到各自对应拉伸应力大小,并计算出每个叶片桨距角的响应变化速率;
对于第k个叶片,其桨距角的响应变化速率和拉伸应力的关系:
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US8240991B2 (en) * | 2011-06-23 | 2012-08-14 | General Electric Company | Method and system for operating a wind turbine |
CN102418663B (zh) * | 2011-12-29 | 2013-12-04 | 一重集团大连设计研究院有限公司 | 一种用于海上大功率风电机组的变桨系统及控制方法 |
US9605558B2 (en) * | 2013-08-20 | 2017-03-28 | General Electric Company | System and method for preventing excessive loading on a wind turbine |
US9995276B2 (en) * | 2014-06-19 | 2018-06-12 | Vestas Wind Systems A/S | Control of wind turbines in response to wind shear |
JP6282187B2 (ja) * | 2014-07-03 | 2018-02-21 | 株式会社日立製作所 | 風車及びその停止方法 |
DE102014225637A1 (de) * | 2014-12-12 | 2016-06-30 | Robert Bosch Gmbh | Verfahren und Vorrichtung zum Überwachen einer Windenergieanlage |
DE102015119986A1 (de) * | 2015-11-18 | 2017-05-18 | Wobben Properties Gmbh | Steuerung einer Windenergieanlage mit verstellbaren Rotorblättern |
CN106968886A (zh) * | 2017-05-18 | 2017-07-21 | 国电联合动力技术有限公司 | 一种风电机组的紧急收桨方法 |
CN108150350A (zh) * | 2017-11-24 | 2018-06-12 | 南京风电科技有限公司 | 一种风力发电机组变速率收桨控制方法 |
-
2018
- 2018-08-06 CN CN201810884863.8A patent/CN109139372B/zh active Active
- 2018-08-22 US US16/762,045 patent/US20200340447A1/en not_active Abandoned
- 2018-08-22 WO PCT/CN2018/101650 patent/WO2020029324A1/zh active Application Filing
Also Published As
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WO2020029324A1 (zh) | 2020-02-13 |
US20200340447A1 (en) | 2020-10-29 |
CN109139372A (zh) | 2019-01-04 |
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