风机变桨系统概述外文翻译

1、中国地质大学长城学院本科毕业论文外文资料翻译系 别： 信息工程系 专 业： 电气工程及其自动化 外文资料翻译译文1 风机变桨系统概述 1.1风力发电机组控制系统硬件分别安装在三个不同部分： 机舱控制，安装在机舱内 。地面控制，安装在塔架底部 。变桨控制，安装在轮毂内部。1.2 人机界面触摸屏显示风机的运行状况和参数，或者启动或停止风机。1.3 风力发电机组四种控制方式： 1.3.1 定速定浆距控制发电机直接连到恒定频率的电网,在发电时不进行空气动力学控制。1.3.2 定速变浆距控制 发电机直接连到恒定频率的电网,在大风时浆距控制用于调节功率。 1.3.3 变速定浆距控制 变频器将发电机和电网去

2、耦(decouples),允许转子速度通过控制发电机的反力矩改变。在大风时,减慢转子直到空气动力学失速限制功率到期望的水平。 1.4 变速变浆距控制 变频器将发电机和电网去耦, 允许通过控制发电机的反力矩改变转子速度。在大风时,浆距控制用于调节功率。2 变桨系统的工作原理 定浆距风机通过叶片的失速,即改变叶片横断面周围流动的气流,导致效率的损失,从而控制风机的最大输出功率。 变浆距风机是通过叶片沿其纵向轴转动,改变气流对叶片的攻角,从而改变风力发电机组获得的空气动力转矩,使发电机功率输出保持稳定。 变桨伺服控制系统作为风力发电控制系统的外环,在风力发电机组的控制中起着十分重要的作用。它控制风力

3、发电机组的叶片节距角可以随风速的大小进行自动调节。在低风速起动时,桨叶节距可以转到合适的角度,使风轮具有最大的起动力矩；当风速过高时,通过调整桨叶节距,改变气流对叶片的攻角,从而改变风力发电机组获得的空气动力转矩,使发电机功率输出保持稳定。3 变桨系统和定桨系统的比较 定桨距失速调节型风力发电机组 定奖距是指桨叶与轮载的连接是固定的，桨距角固定不变，即当风速变化时，桨叶的迎风角度不能随之变化,桨叶翼型本身所具有的失速特性。当风速高于额定风速时，气流的攻角增大到失速条件，使桨叶的表面产生涡流，效率降低，来限制发电机的功率输出。为了提高风电机组在低风速时的效率，通常采用双速发电机（即大/小发电机）

4、。在低风速段运行的，采用小电机使桨叶县有较高的气动效率，提高发电机的运行效率。 失速调节型的优点是失速调节简单可靠，当风速变化引起的输出功率的变化只通过桨叶的被动失速调节而控制系统不作任何控制，使控制系统大为减化。其缺点是叶片重量大（与变桨距风机叶片比较），桨叶、轮载、塔架等部件受力较大，机组的整体效率较低。 变桨距调节型风力发电机组是指通过变桨驱动装置,带动安装在轮毂上的叶片转动, 从而改变叶片桨距角的大小。其调节方法为：当风电机组达到运行条件时，控制系统命令变桨系统将桨距角调到45，当转速达到一定时，再调节到0，直到风力机达到额定转速并网发电；在运行过程中，当输出功率小于额定功率时，桨距角

5、保持在0位置不变，不作任何调节；当发电机输出功率达到额定功率以后，调节系统根据输出功率的变化调整桨距角的大小，使发电机的输出功率保持在额定功率。 缺点是结构比较复杂，故障率相对较高。4 变桨系统的分类 4.1 变桨距系统根据其工作方式可分为统一变桨和独立变桨二种方式 统一变桨距控制即机组所有桨叶都由一个执行机构驱动，或者三个执行机构同时驱动,桨叶节距角变化相同。由于液压系统力矩大，在大型风力机统一变桨距方式一般都采用液压方式。 独立变桨距方式，每个桨叶都由独立的变桨距执行机构驱动，如果其中一个变桨距执行结构出现故障，其它两个桨叶仍能调节桨叶节距角,实现功率控制，而统一变桨距执行结构出现故障，只

6、能停机维修；另外自然界的风在整个风轮扫及面上分布是不均匀的，独立桨叶控制可以根据各个桨叶上的风速不同进行调节，不仅能维持发电机输出功率，而且能减小桨叶拍打振动，因此独立桨叶控制比统一控制更具有一定的优势。独立变桨距控制将桨叶负载分别由单一的执机构承担，所以一般都采用电机执行方式，电动机通过主动 齿轮带动桨叶轮毂内齿圈，使桨叶节距角发生改变。但变桨距过程桨叶节距 角变化只是0 到90。 但风力机组风速传感器安装在风轮后的机舱上，不能正确反映扫及面上的风速，因此控制时一般都以发电机额定功率或转子转速为界，即当发电机输出功率（转速）低于额定值时，进行变速恒频控制，最大捕获风能；而当输出功率（转速）高

7、于额定值时，进行变桨距控制，维持发电机功率在额定值附近。 要实现真正的独立变桨,输入变量包括桨叶节距角变化和风速，以及每个桨叶受力等,实现多变量控制，但由于风速传感器不能反映每个桨叶上的风速情况，而且复杂的控制程序也很难在工程中实现，所以目前工程上仍然采用统一变桨，即三个桨叶同时动作。 4.2根据执行机构的类型可分为液压变桨和电动变桨。 4.3电动变桨根据所用电机可以分为直流伺服和交流伺服两种类型。 4.3.1直流型电变桨伺服控制系统 直流型变桨系统主要由以下特点：采用串激直流电机,起动力矩大。对于转动重达数吨直径数十米的叶片有好处； 由于采用直流无级调速,低速性能好； 不允许空载运行,否则会

8、引起“飞车”； 电机有碳刷,维修困难； 加后备电池比较方便。 4.3.2交流型电变桨伺服控制系统 交流型变桨系统主要由以下特点： 采用交流永磁同步电机或交流异步电机,结构简单维修工作量小； 代表了伺服控制系统的发展方向； 必须加ups；以便在电网突然断电或其它紧急情况停机时, 变桨伺服系统可以通过自备的ups短暂供电,使变桨系统完成收桨及采取予定的其它安全措施。 5 变桨系统的组成 变桨系统主要由plc可逆直流调速装置直流电机绝对式位置编码器等组成,并由蓄电池作为后备电源。 plc组成变浆的控制系统,它通过现场总线(例如can总线)和主控制系统通信,接受主控制系统的指令(主要是桨叶转动的速度和

9、角度指令),并控制可逆直流调速装置驱动直流电机带动桨叶朝要求的方向和角度转动,同时plc还负责蓄电池的充电控制蓄电池电压的监控等辅助控制。6 主要技术性能指标 6.1伺服电机 额定转速 2500 rpm 额定输出电流 17a 额定转矩 20.0 nm 电源电压 三相ac380v 绝缘等级 f级 冷却方式 自然冷却 防护等级 ip64 环境温度 2540 制动装置 选件 编码器 绝对值位置编码器 6.2伺服驱动系统 额定输出功率 7.5kw 额定输出电流 24a 额定输出电压 30-400v(ac) 输入电压 3ac380v(2510) 过载能力 43a/30秒 冷却方式 散热器外置自然冷却 防

10、护等级 ip24或更高 环境温度 2540 制动电阻 外加 配置现场总线 can总线 保护功能 电机三相短路保护过载保护电源过压保护等外文原文1 fan pitch system overview1.1 wind turbine control system hardware were installed in three different parts the cabin control, installed inside the cabin.ground control, mounted on the bottom of the tower.pitch control, internall

11、y mounted on the hub.1.2 man-machine interface the touch screen displays the operational status and parameters of the fan, or to start or stop the fan.1.3 wind turbine the four control way1.3.1 constant speedgivenpitchcontrolthegenerator is directlyconnected to theconstant frequencyof the grid,theae

12、rodynamic controlis not performedwhenthepower generation.1.3.2 constant speed variable pitch controlthe generator is directly connected to the constant frequency of the power grid, power is used to adjust the pitch control in high winds.1.3.3 variable speed and pitch controlthe inverter of the gener

13、ator and grid decoupling (decouples), to allow the rotor speed by the anti-torque control of the generator changes. in high winds, slow down the rotor until aerodynamic stall limit power to the desired level.1.4 variable speed pitch controlinverter generator and grid decoupling change permitted by t

14、he anti-torque control of the generator rotor speed. in high winds, the pitch control is used to adjust the power.2 pitch system worksfixed pitch by a stall of the blade, i.e. to change the airflow flowing around the blade cross section, resulting in a loss of efficiency, thereby controlling the max

15、imum output power of the blower fan.the variable pitch fan is through the vanes to rotate along its longitudinal axis to change the angle of attack of the airflow to the blades, thereby changing the the aerodynamic torque obtained by the wind turbine generator, so that the generator power output sta

16、ble.pitch servo control system as the outer ring of wind power control system, plays a very important role in the control of the wind turbine. it controls the blade pitch angle of the wind turbine can automatically adjust the size of the wind velocity. the start of the low wind speed, the blade pitc

17、h can go to the right angle, so that the wind wheel has a maximum starting torque;, thereby changing wind when the wind velocity is too high, by adjusting the blade pitch, and to change the angle of attack of the airflow to the blades aerodynamic torque obtained by the generator set, the generator p

18、ower output to maintain stability.3 pitch system and the comparison of fixed-blade systemfixed-blade away from the stall adjustment type wind turbine given award from the connection of the paddle wheel load is fixed, the pitch angle is fixed, that is, when the wind changes, the windward angle of the

19、 blade can not be changes, bladethe airfoil itself has stall characteristics. when the wind speed is higher than the rated wind speed, the angle of attack of the air flow is increased to a stall condition, the eddy current is generated on the surface of the blades, reducing efficiency, and to limit

20、the power output of the generator. in order to improve the efficiency of wind turbines in low wind speeds, usually a two-speed generator (ie, large / small generator). segment running at low wind speeds, using a small motor to the blades county high aerodynamic efficiency and to improve the operatin

21、g efficiency of the generator. stall adjusting the advantages of the type stall regulation is simple and reliable, passive stall regulated only by the blades when the wind speed changes caused by variations in output power and the control system without any control, the control system greatly reduce

22、d. the disadvantage is that the weight of leaves (comparison with variable pitch fan blades), paddle wheel load, tower components by a larger force, and lower the overall efficiency of the unit.the pitch adjustment wind turbines generating means through the pitch drive means, driving the rotation of

23、 the blades mounted on the hub, thereby changing the size of the blade pitch angle. adjustment method: when the wind turbine operating conditions, the control system commands pitch pitch angle adjusted to 45 , and then adjusted to 0 when the speed reaches a certain reach the rated speed until the wi

24、nd turbine to the grid; during operation, when the output power is less than the rated power, the pitch angle to maintain the same, does not make any adjustment in the 0 position; reach rated power when the generator output power, the regulation system adjusted according to the changes in the output

25、 power of the pitch angle size, so that the output power of the generator is maintained at the rated power. the disadvantage is that the more complex structure, a relatively high failure rate.4 pitch classification4.1 variable pitch unified pitch and independent pitch system in accordance with its w

26、ork can be divided into two kinds of waysunified variable pitch control that crew all blades by an executive agency drive, or drive three implementing agencies, the blade pitch angle changes. the torque of the hydraulic system, unified in a large wind turbine pitch distance is generally hydraulicall

27、y.independent variable pitch mode, each blade by the independent pitch actuator driver, if one pitch implementation of structural failure, and the other two blades can still adjust the blade pitch angle, the power control, unified pitch implementation of structural failure, only a maintenance shutdo

28、wn; further, the nature of the wind in the sweep of the entire wind wheel and the surface is not uniformly distributed, independent blade control may be adjusted depending on the wind speed on the respective blades, not only to maintain the generator output power, but also can reduce the blade flapp

29、ing vibration, independent blade control more than unified control has certain advantages. independent variable pitch control blade load borne by a single executive agency, so generally used motor execution, motor internal ring gear paddle wheels driven by the drive gear, the blade pitch angle chang

30、es. but the pitch process changes in the pitch angle of the blade only from 0 to 90 . but on wind turbines wind speed sensor is installed in the cabin after the wind wheel, can not correctly reflect the sweep and surface wind speed, control generator rated power or rotor speed is bounded generally l

31、ow, that is, when the generator output power (speed) rated vscf control, maximum capture of wind energy; higher than the rated output power (speed), pitch control and maintain the generator power rating near. to achieve a truly independent pitch input variables, including changes in blade pitch angl

32、e and wind speed, and each blade force multivariable control, but because of the wind speed sensor does not reflect the wind speed on each blade, and the complexity of the control program it is difficult to achieve in the project, so the project still unified pitch, that the three blades at the same

33、 time.4.2 can be divided according to the type of the implementing agency the hydraulic pitch, and the electric pitch.4.3 electric pitch depending on the motor can be divided into two types of dc servo and ac servo.4.3.1 dc electric pitch servo control systemdc pitch system mainly consists of the fo

34、llowing characteristics: a series wound dc motor starting torque. tens of meters in diameter blade rotation weighing several tons, is good; dc stepless speed, low-speed performance; does not allow no-load operation, otherwise it would cause speed; motor carbon brush, maintenance difficulties; canadi

35、an the backup battery is more convenient.4.3.2 ac electric pitch servo control systemac-type pitch system mainly consists of the following characteristics: ac permanent magnet synchronous motors, or ac induction motor, simple structure, maintenance workload is small; represents the development direc

36、tion of the servo control system; must be added to the ups; sudden power failure so that the grid or otheremergency shutdown, the pitch servo system can briefly owned the ups power supply system to complete the closing paddle and take other safety measures predetermined pitch.5 the composition of the pitch systemthe pitch system mainly by the plc, reversible, absolute position encoder dc speeder, dc motor by the battery as a backup power supply. plc composed o