风机变桨系统概述外文翻译

1、核准通过，归档资料。未经允许，请勿外传！9JWKffwvG#tYM*Jg&6a*CZ7H$dq8KqqfHVZFedswSyXTy#&QA9wkxFyeQ!djs#XuyUP2kNXpRWXmA&UE9aQGn8xp$R#, 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 g

2、enerator set, the generator power 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 chang

3、es, the windward angle of the 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, reduc

4、ing efficiency, and to limit 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 efficienc

5、y and to improve the operating 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

6、control system greatly reduced. 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 m

7、eans, driving the rotation of 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

8、 the rated speed until the wind 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

9、 to the changes in the output 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 sy

10、stem in accordance with its work 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 dista

11、nce is generally hydraulically.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 failu

12、re, only a maintenance shutdown; 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 al

13、so can reduce the blade flapping 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

14、, the blade pitch angle changes. 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

15、 speed is bounded generally low, 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, includin

16、g changes in blade pitch angle 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

17、 the three blades at the same 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 sys

18、tem mainly consists of the following 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, mai

19、ntenance difficulties; Canadian 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; rep

20、resents the development direction 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

21、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 of the pitch control system via fieldbus (eg CAN bus) and the main control system communication, to accept t

22、he instruction of the main control system (mainly the instructions of the speed and angle of blades), and control reversible DC speeder driver DC motor driven by the blades toward the required direction and angle of rotation, while the PLC is also responsible for the assist control of the charging control of the battery, the battery voltage monitoring.6 main technical