CN116146415A - Variable pitch cooperative control method and system for double EHA driving independent variable pitch system - Google Patents
Variable pitch cooperative control method and system for double EHA driving independent variable pitch system Download PDFInfo
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Abstract
The invention relates to a variable pitch cooperative control method of a double EHA driving independent variable pitch system, which comprises the following steps of: based on wind field SCADA and wind turbine generator set data, establishing a variable pitch system load and unit power prediction model; step 2: obtaining a predicted value of the variable-pitch load of the unit and the unit power by using a variable-pitch load and unit power prediction model; step 3: establishing a control link of the first driving unit according to the pitch angle instruction and the pitch load predicted value; step 4: establishing a control link of a second driving unit according to the pitch load predicted value and a speed error feedback signal of the first driving unit; step 5: the first driving unit and the second driving unit are cooperatively controlled, so that the cooperative control of the double driving units is realized. According to the invention, the pitch controller receives the pitch instruction of the main control system, and controls the two sets of driving units to respectively control the position and the pressure, so that the high-precision and high-dynamic tracking of the pitch angle instruction of the main control system by the dual-drive independent pitch system is realized.
Description
Technical Field
The application relates to the technical field of wind power generation, in particular to a variable pitch cooperative control method and a system of a double EHA driving independent variable pitch system.
Background
The wind turbine generator pitch system is a core system for safe, stable and efficient operation of the wind turbine generator. However, the pitch system has the problems of high failure rate, high maintenance cost and the like. In addition, the large-scale wind turbine generator and the continuous development of offshore wind power provide higher requirements on stability, reliability, high efficiency and the like of a variable pitch system.
The load of a pitch system is increased due to the large-scale wind turbine generator, and the single-drive pitch system cannot meet the requirement of a pitch driving system due to limited driving force; in addition, the single-drive pitch system has the problems of radial unbalanced load and overlarge local load, so that a reliable pitch system which is more suitable for a large-capacity unit needs to be designed. Wherein a dual (multi) drive pitch system is an effective solution.
In the prior art document with the name of a direct-drive hydraulic variable pitch control mechanism for a wind driven generator, the variable pitch mechanism is driven by two sets of closed pump-controlled hydraulic systems, and when one set of variable pitch driving system hydraulic circuits fails and loses pressure, the control system is automatically switched to the hydraulic circuit of the second set of driving system, so that the redundant design of the variable pitch system is realized, and the reliability of the system is improved. However, the system realizes pitch by one hydraulic cylinder, and the problems of radial offset load and overlarge local load still exist. In another prior art document named as a variable pitch double motor drive control system of a wind generating set, the double drive control can evenly distribute load, so that the output of a single driver is smaller, further, fatigue load loaded on a bearing tooth surface can be reduced, the service life of a variable pitch bearing is prolonged, and double motor synchronous control is realized. In addition, in the prior art document named as a control method and a device of a double-motor pitch system, a main motor and a secondary motor are respectively controlled, so that one part of target torque of the motor is output by the main motor, and the other part of target torque of the motor is output by the secondary motor, the coordination control of the main motor and the secondary motor is realized, and the blades can reach the target position. From the disclosure of the above documents it is known that the electric pitch technology is relatively mature, and how to better combine the advantages of a hydraulic system with a large pitch system is yet to be explored further.
Disclosure of Invention
In order to overcome the defects in the prior art, the pitch controller receives the pitch instruction of the main control system, and controls the two sets of EHA (closed pump control hydraulic system) driving units to respectively control the position and the pressure, so that the high-precision and high-dynamic tracking of the pitch angle instruction of the main control system by the double EHA driving independent pitch system is realized.
In order to achieve the above object, the solution adopted by the present invention is: a variable pitch cooperative control method of a double EHA driving independent variable pitch system comprises the following steps:
step 1: based on wind field SCADA (data acquisition and monitoring control system) and wind motor group data, establishing a variable pitch system load and unit power prediction model;
acquiring long-term SCADA data and wind turbine generator system data in a wind field, cleaning the data, and carrying out normalization processing to obtain a normalization result x of a state quantity and a normalization result y of an actual quantity; taking the normalization result x= { v, w, θ, β, Δψ } of the state quantity as the input of the neural network, the normalization result y= { P, T of the actual quantity Z And (2) outputting the model as a neural network, and training a variable-pitch system load and unit power prediction model through an artificial neural network to obtain the variable-pitch system load and unit power prediction model, wherein the variable-pitch system load and unit power prediction model is as follows:
Wherein: t (T) Z Representing an actual value of pitch load; p represents the actual value of the unit power; x= { v, w, θ, β, Δψ } is represented asNormalization results of state quantity; v represents the wind wheel plane wind speed; w represents the rotational speed of the wind wheel; θ represents the blade azimuth angle; beta represents the blade pitch angle; Δψ represents yaw angle error; f (f) 1 Representing a variable pitch load neural network model; f (f) 2 Representing a power neural network model of the unit;
step 2: obtaining a predicted value of the variable-pitch load of the unit and the unit power by using a variable-pitch load and unit power prediction model;
the state quantity x= { v, w, θ, β, Δψ } which is monitored and collected by the unit main control system in real time; substituting the normalized state quantity into a unit variable pitch load model and a unit power prediction model to obtain a unit variable pitch load and a unit power prediction value of T Znorm ，P norm Then, the inverse normalization treatment is carried out, and the treatment process is as follows:
wherein: y represents the normalization result of the actual quantity; y is norm Representing a predicted value of the variable pitch load of the unit; y is max Representing a predicted value of the unit power; y is min A minimum value representing the actual quantity;
step 3: establishing a control link of the first EHA driving unit according to the pitch angle instruction and the pitch load predicted value;
converting the pitch angle command signal into a displacement signal of a first hydraulic cylinder, and controlling the displacement of a hydraulic cylinder piston rod of the pitch system, wherein a calculation model of the displacement command signal of the first hydraulic cylinder is as follows:
Wherein: l (L) in Representing a first hydraulic cylinder displacement command signal; r represents the turning radius of the end part of the piston rod of the first hydraulic cylinder; h represents the distance from the first cylinder mounting hinge to the center of the vane; alpha represents the turning radius of the piston rod end part of the first hydraulic cylinder and the first hydraulic cylinder is hinged to the center of the blade when the pitch angle position is 0 DEGAn included angle of the connecting lines; l (L) min The distance from the end of the piston rod to the position of the first hydraulic cylinder mounting hinge when the pitch angle is 0 degrees is represented;
the pitch controller commands the pitch angle of the main control system to be beta in Is converted into a displacement command signal l of a first hydraulic cylinder in Designing a control link of the first EHA driving unit to realize the motion control of the first hydraulic cylinder;
step 4: establishing a control link of a second EHA driving unit according to the pitch load predicted value and a speed error feedback signal of the first EHA driving unit;
the pitch controller predicts a pitch load predictive value T Znorm Converted into a second hydraulic cylinder driving force command F in The relationship between the two is as follows:
wherein: f (F) in Representing a second hydraulic cylinder driving force command parameter; t (T) Znorm Representing a predicted value of the variable pitch load of the unit;
step 5: the first EHA driving unit and the second EHA driving unit are cooperatively controlled to realize cooperative control of the double EHA driving units;
And (3) acquiring dynamic high-precision tracking of pitch angle instructions of the main control system by the dual-EHA driving independent pitch-changing system by cooperatively driving the blades by the first EHA driving unit and the second EHA driving unit in the steps (3) and (4), and finally, cooperatively controlling the dual-EHA driving unit.
Preferably, the step 1 of acquiring long-term SCADA data and wind turbine generator system data in a wind field, cleaning the data, and performing normalization processing, specifically includes:
the content of the long-term SCADA data and the wind turbine group data in the wind field covers v under all wind conditions in ≤v≤v out Operating state data v of (v) in Represents cut-in wind speed, v out Indicating the cut-out wind speed;
the data are cleaned to remove the data of the shutdown state of the unit, the acquisition errors of the sensor and the interference;
long-term SCADA data and wind turbine group data in a wind field are acquired, cleaning data are subjected to normalization processing, and the processing procedure is as follows:
wherein: x is x norm A normalization result representing the state quantity; x is x s An input value representing a state quantity; x is x min Representing a minimum value of the state quantity; x is x max A maximum value representing a state quantity; y represents an input value of the actual quantity; y is norm A normalization result representing the actual quantity; y is max A maximum value representing the actual amount; x= { v, w, θ, β, Δψ } includes the rotor plane wind speed v, rotor speed w, blade azimuth angle θ, blade pitch angle β, and yaw angle error Δψ.
Preferably, in the step 3, a control link of the first EHA driving unit is established according to the pitch angle command and the pitch load predicted value, specifically:
design feedforward control link C 2 (s) realizing the displacement command l of the first hydraulic cylinder in Is a fast track of (2); the first hydraulic cylinder displacement command signal l in And comparing the displacement feedback signal with the displacement feedback signal l of the first hydraulic cylinder to obtain a displacement difference value of the first hydraulic cylinder, wherein the displacement difference value is as follows:
e l ＝l in -l；
wherein: e, e l Representing a first hydraulic cylinder displacement difference; l represents a first hydraulic cylinder displacement feedback signal;
design error compensation controller C 1 (s) compensating for the error, eliminating steady state error;
according to the predicted value T of the variable pitch load Z Design feedforward compensation control C 3 (s) compensating;
adding the three control links to obtain a rotation speed control instruction omega of the servo motor in the first EHA driving unit in The following is shown:
ω in (s)＝e l C 1 (s)+l in C 2 (s)+F z C 3 (s)；
wherein: omega in (s) represents a rotational speed control instruction of the servo motor in the first EHA drive unit; c (C) 1 (s) represents a first error compensation control section; c (C) 2 (s) represents a second feedforward control component; c (C) 3 (s) represents a third feedforward compensation control component; f (F) z Representing feedback parameters of a third feedforward compensation control link; s represents a differential operator;
servo driver for controlling servo motor rotation speed to track rotation speed command omega in The bidirectional fixed displacement hydraulic pump is driven to supply oil to the first hydraulic cylinder, and the first hydraulic cylinder is controlled to move.
Preferably, in the step 4, a control link of the second EHA driving unit is established according to the pitch load predicted value and the speed error feedback signal of the first EHA driving unit, specifically:
design feedforward control link C 5 (s) realizing the driving force instruction F for the second hydraulic cylinder in Is a fast track of (2); second hydraulic cylinder driving force command signal F in With the second cylinder driving force feedback signal p B K 3 And comparing to obtain a second hydraulic cylinder driving force difference value, wherein the second hydraulic cylinder driving force difference value is as follows:
e f ＝F in -p B K 1 ；
wherein: e, e f Representing a second hydraulic cylinder drive force difference; f (F) in A second hydraulic cylinder driving force instruction signal; p is p B Representing the high pressure chamber pressure of the second hydraulic cylinder; k (K) 1 Representing the feedback coefficient;
design error compensation controller C 4 (s) compensating for the error, eliminating steady state error; and simultaneously, the variable pitch controller feeds back a difference value according to the speed of the first hydraulic cylinder, as follows:
e v ＝l in s-ls；
wherein: e, e v Representing a speed feedback difference value of the variable pitch controller according to the first hydraulic cylinder; s represents a differential operator;
design feedforward compensation controller C 6 (s) performing a velocity compensation;
adding the three control links to obtain a torque control instruction T of the servo motor in the second EHA driving unit in The following is shown:
T in (s)＝e f C 4 (s)+F in C 5 (s)+e v C 6 (s)；
wherein: t (T) in (s) represents a torque control command of the servo motor in the second EHA drive unit; c (C) 4 (s) represents a second error compensation control section; c (C) 5 (s) represents a fifth feedforward compensation control component; c (C) 6 (s) represents a sixth feedforward compensation control step;
servo driver control servo motor torque tracking torque command T in The bidirectional fixed displacement hydraulic pump is driven to supply oil to the second hydraulic cylinder, so that the second hydraulic cylinder generates driving force.
The second aspect of the present invention provides a pitch control system based on the foregoing pitch cooperative control method of a dual EHA driven independent pitch system, capable of implementing cooperative control of the dual EHA driven independent pitch system, the pitch control system includes: the wind turbine generator system comprises a wind turbine generator system main control system, a variable pitch controller, a first EHA driving unit, a second EHA driving unit and a variable pitch bearing;
the main control system of the wind turbine is mainly used for detecting and controlling the state of the whole wind turbine, and controlling the pitch system by combining the running state of the wind turbine and the wind condition;
the pitch angle command of the main control system is converted into a rotating speed command of a first servo motor of the first EHA driving unit by the pitch controller, and a torque command of a servo motor of the second EHA driving unit is set by combining the predicted pitch load and the pressure feedback of two cavities of the hydraulic cylinder; the variable pitch controller respectively performs position control and pressure control on the first EHA driving unit and the second EHA driving unit, so that dynamic high-precision tracking of the pitch angle instruction of the main control system by the dual-EHA driving independent variable pitch system is realized;
The first EHA driving unit comprises a first servo driver, a first servo motor, a first bidirectional fixed displacement pump, a first hydraulic control one-way valve, a second hydraulic control one-way valve, a first overflow valve, a second overflow valve, a first electromagnetic switch valve, a second electromagnetic switch valve, a third electromagnetic switch valve, a fourth electromagnetic switch valve, a fifth electromagnetic switch valve, a sixth electromagnetic switch valve, a first closed oil tank, a first emergency energy accumulator, a first hydraulic cylinder, a first displacement sensor, a first rodless cavity pressure sensor and a first rod cavity pressure sensor; the first servo driver is connected with the first servo motor and controls the rotating speed and the torque of the first servo motor; the first servo motor is coaxially connected with the first bidirectional fixed displacement pump; the P port of the first bidirectional fixed displacement pump is respectively connected with the P port of the fifth electromagnetic switch valve, the P port of the sixth electromagnetic switch valve, the Q port of the second overflow valve, the Q port of the second hydraulic control one-way valve and the control oil port of the first hydraulic control one-way valve; the Q port of the bidirectional fixed displacement pump is respectively connected with the P port of the first electromagnetic switch valve, the P port of the second overflow valve, the Q port of the first hydraulic control one-way valve and the control oil port of the second hydraulic control one-way valve; the P port of the first hydraulic control one-way valve is respectively connected with the Q port of the first overflow valve, the P port of the second electromagnetic switch valve, the oil port of the first closed oil tank, the P port of the third electromagnetic switch valve, the Q port of the second overflow valve and the P port of the second hydraulic control one-way valve; the P port of the fourth electromagnetic switch valve is respectively connected with the oil port of the first emergency accumulator and the Q port of the sixth electromagnetic switch valve; the rodless cavity of the first hydraulic cylinder is connected with the first rodless cavity pressure sensor, the Q port of the third electromagnetic switch valve, the Q port of the fourth electromagnetic switch valve and the Q port of the fifth electromagnetic switch valve respectively; the rod cavity of the first hydraulic cylinder is respectively connected with the Q port of the first electromagnetic switch valve, the P port of the second electromagnetic switch valve and the first rod cavity pressure sensor; the first displacement sensor is arranged on the first hydraulic cylinder and used for monitoring the displacement of a piston rod of the hydraulic cylinder; the second EHA driving unit comprises a second servo driver, a second servo motor, a second bidirectional fixed displacement pump, a third hydraulic control one-way valve, a fourth hydraulic control one-way valve, a third overflow valve, a fourth overflow valve, a seventh electromagnetic switch valve, an eighth electromagnetic switch valve, a ninth electromagnetic switch valve, a tenth electromagnetic switch valve, an eleventh electromagnetic switch valve, a twelfth electromagnetic switch valve, a second closed oil tank, a second emergency accumulator, a second hydraulic cylinder, a second displacement sensor, a second rodless cavity pressure sensor and a second rod cavity pressure sensor;
The second servo driver is connected with the second servo motor and controls the rotating speed and the torque of the second servo motor; the second servo motor is coaxially connected with the second bidirectional constant displacement pump; the P port of the second bidirectional constant displacement pump is respectively connected with the P port of the eleventh electromagnetic switch valve, the P port of the twelfth electromagnetic switch valve, the Q port of the fourth overflow valve, the Q port of the fourth hydraulic control one-way valve and the control oil port of the third hydraulic control one-way valve; the Q port of the second bidirectional constant displacement pump is respectively connected with the P port of the seventh electromagnetic switch valve, the P port of the fourth overflow valve, the Q port of the third hydraulic control one-way valve and the control oil port of the fourth hydraulic control one-way valve; the P port of the third hydraulic control one-way valve is respectively connected with the Q port of the third overflow valve, the P port of the eighth electromagnetic switch valve, the oil port of the second closed oil tank, the P port of the ninth electromagnetic switch valve, the Q port of the fourth overflow valve and the P port of the fourth hydraulic control one-way valve; the P port of the tenth electromagnetic switch valve is respectively connected with the oil port of the second emergency accumulator and the Q port of the twelfth electromagnetic switch valve; the rodless cavity of the second hydraulic cylinder is respectively connected with the second rodless cavity pressure sensor, the Q port of the ninth electromagnetic switch valve, the Q port of the tenth electromagnetic switch valve and the Q port of the eleventh electromagnetic switch valve; the rod cavity of the second hydraulic cylinder is respectively connected with the Q port of the seventh electromagnetic switch valve, the port of the eighth electromagnetic switch valve and the second rod cavity pressure sensor; the second displacement sensor is arranged on the second hydraulic cylinder and is used for monitoring the displacement of a piston rod of the second hydraulic cylinder;
The variable-pitch bearing outer ring is fixed on the hub, the variable-pitch bearing inner ring is fixedly connected with the root of the blade and the torque transmission disc, the first hydraulic cylinder and the second hydraulic cylinder are arranged in parallel and opposite, the tail parts of rod cavities of the first hydraulic cylinder and the second hydraulic cylinder are respectively connected with the hub through hinges, and the end parts of piston rods of the first hydraulic cylinder and the second hydraulic cylinder are respectively connected with the torque transmission disc through joint bearings.
Compared with the prior art, the invention has the beneficial effects that:
(1) The double EHA driving independent variable pitch system adopted by the invention comprises two EHA driving units, and the highly integrated closed pump control hydraulic system (EHA) driving units do not need a hydraulic slip ring and a long pipeline, so that the risk of oil leakage is reduced, and the maintenance is convenient and fast; the two EHA driving units are arranged in parallel and opposite, cooperatively drive the blades to change the pitch, and have large driving force and small radial unbalanced load.
(2) According to the invention, by predicting the pitch load and respectively carrying out position high-precision control and pressure compensation control on the first EHA driving unit and the second EHA driving unit, the high-precision and high-dynamic tracking of the pitch angle instruction of the main control system by the dual-EHA driving independent pitch system can be realized.
Drawings
FIG. 1 is a control block diagram of a pitch cooperative control method of a dual EHA driven independent pitch system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a dual EHA drive independent pitch system according to an embodiment of the present invention;
FIG. 3 is a schematic view of a pitch actuator according to an embodiment of the present invention;
FIG. 4 is a schematic view of a hydraulic lever structure of a pitch actuator according to an embodiment of the present invention;
FIG. 5 is a flowchart of a method for switching control modes of a pitch system according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a control system of a pitch cooperative control method in an embodiment of the present invention;
FIG. 7 is a training flow chart of a variable pitch system load and unit power prediction model in an embodiment of the invention.
The main reference numerals:
1. a first servo driver; 2. a first servo motor; 3. a first bi-directional fixed displacement pump; 4. a first pilot operated check valve; 5. a first overflow valve; 6. a first electromagnetic switching valve; 7. a second electromagnetic switching valve; 8. a first displacement sensor; 9. a torque transmission disc; 10. a pitch bearing; 11. a first hydraulic cylinder; 12. a first rodless cavity pressure sensor; 13. a first closed oil tank; 14. a third electromagnetic switching valve; 15. a fourth electromagnetic switching valve; 16. a fifth electromagnetic switching valve; 17. a first emergency accumulator; 18. a sixth electromagnetic switching valve; 19. a second overflow valve; 20. a second pilot operated check valve; 21. a first rod cavity pressure sensor; 22. a pitch controller; 23. a master control system; 24. a second servo driver; 25. a second servo motor; 26. a second bi-directional fixed displacement pump; 27. a third pilot operated check valve; 28. a third overflow valve; 29. a seventh electromagnetic switching valve; 30. an eighth electromagnetic switching valve; 31. a second rod cavity pressure sensor; 32. a second displacement sensor; 33. a second hydraulic cylinder; 34. a second rodless cavity pressure sensor; 35. a second closed oil tank; 36. a ninth electromagnetic switching valve; 37. a tenth electromagnetic switching valve; 38. an eleventh electromagnetic switching valve; 39. a second emergency accumulator; 40. a twelfth electromagnetic switching valve; 41. a fourth overflow valve; 42. a fourth pilot operated check valve; 43. a hub; 44. a blade; A. a first EHA driving unit, a B and a second EHA driving unit.
Detailed Description
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The double EHA driving independent variable pitch system adopted by the embodiment of the invention comprises two EHA driving units, and the highly integrated closed pump control hydraulic system (EHA) driving units do not need a hydraulic slip ring and a long pipeline, so that the risk of oil leakage is reduced, and the maintenance is convenient and fast; the two EHA driving units are arranged in parallel and opposite, cooperatively drive the blades to change the pitch, and have large driving force and small radial unbalanced load; the high-precision and high-dynamic tracking of the pitch angle instructions of the main control system by the double-EHA driving independent pitch-varying system can be realized by predicting the pitch load and respectively carrying out position high-precision control and pressure compensation control on the first EHA driving unit A and the second EHA driving unit B. Fig. 1 is a control block diagram of a pitch cooperative control method of a dual EHA driven independent pitch system according to an embodiment of the present invention.
The embodiment of the invention provides a variable pitch cooperative control method of a double EHA driving independent variable pitch system, and a flow chart of the embodiment of the invention is shown in FIG. 2; to demonstrate the applicability of the invention, it is applied to examples, comprising in particular the following steps:
s1: based on wind field SCADA and wind turbine generator set data, a variable pitch system load and unit power prediction model is established.
And acquiring long-term SCADA data and wind turbine generator system data in a wind field, cleaning the data, and carrying out normalization processing to obtain a normalization result x of the state quantity and a normalization result y of the actual quantity.
The content of the long-term SCADA data and the wind turbine group data in the wind farm covers v under all wind conditions in ≤v≤v out Operating state data v of (v) in Represents cut-in wind speed, v out Indicating the cut-out wind speed; the data are cleaned to remove the data of the shutdown state of the unit, the acquisition errors of the sensor and the interference; long-term SCADA data and wind turbine group data in a wind field are acquired, cleaning data are subjected to normalization processing, and the processing procedure is as follows:
wherein: x is x norm A normalization result representing the state quantity; x is x s An input value representing a state quantity; x is x min Representing a minimum value of the state quantity; x is x max A maximum value representing a state quantity; y represents an input value of the actual quantity; y is norm A normalization result representing the actual quantity; y is max A maximum value representing the actual amount; x= { v, w, θ, β, Δψ } includes the rotor plane wind speed v, rotor speed w, blade azimuth angle θ, blade pitch angle β, and yaw angle error Δψ.
Taking the normalization result x= { v, w, θ, β, Δψ } of the state quantity as the input of the neural network, the normalization result y= { P, T of the actual quantity Z As a neural network output, training a variable pitch system load and unit power prediction model through an artificial neural network, as shown in fig. 7, which is a flowchart of training the variable pitch system load and unit power prediction model in the embodiment of the invention, to obtain a variable pitch system load and unit power prediction model, as shown in the following:
Wherein: t (T) Z Representing an actual value of pitch load; p represents the actual value of the unit power; x= { v, w, θ, β, Δψ } represents the normalization result of the state quantity; v represents the wind wheel plane wind speed; w represents the rotational speed of the wind wheel; θ represents the blade azimuth angle; beta represents leafA pitch angle of the blade; Δψ represents yaw angle error; f (f) 1 Representing a variable pitch load neural network model; f (f) 2 Representing a power neural network model of the unit.
S2: and obtaining a predicted value of the variable-pitch load and the unit power of the unit by using the variable-pitch load and unit power prediction model.
The state quantity x= { v, w, θ, β, Δψ } which is monitored and collected by the unit main control system in real time; substituting the normalized state quantity into a unit variable pitch load model and a unit power prediction model to obtain a unit variable pitch load and a unit power prediction value of T Zn orm，P norm Then, the inverse normalization treatment is carried out, and the treatment process is as follows:
wherein: y represents the normalization result of the actual quantity; y is norm Representing a predicted value of the variable pitch load of the unit; y is max Representing a predicted value of the unit power; y is min Representing the minimum of the actual quantity.
S3: and establishing a control link of the first EHA driving unit A according to the pitch angle command and the pitch load predicted value.
Design feedforward control link C 2 (s) realizing the displacement command l of the first hydraulic cylinder in Is a fast track of (2); the first hydraulic cylinder displacement command signal l in And comparing the displacement feedback signal with the displacement feedback signal l of the first hydraulic cylinder to obtain a displacement difference value of the first hydraulic cylinder, wherein the displacement difference value is as follows:
e l ＝l in -l；
wherein: e, e l Representing a first hydraulic cylinder displacement difference; l represents a first hydraulic cylinder displacement feedback signal.
Design error compensation controller C 1 And(s) compensating the error, and eliminating the steady-state error.
According to the predicted value T of the variable pitch load Z Design feedforward compensation control C 3 (s) compensating.
Adding the three control links to obtain a first EHA driveRotation speed control command omega of first servo motor in moving unit A in The following is shown:
ω in (s)＝e l C 1 (s)+l in C 2 (s)+F z C 3 (s)；
wherein: omega in (s) represents a rotational speed control instruction of the servo motor in the first EHA drive unit; c (C) 1 (s) represents a first error compensation control section; c (C) 2 (s) represents a second feedforward control component; c (C) 3 (s) represents a third feedforward compensation control component; f (F) z Representing feedback parameters of a third feedforward compensation control link; s denotes a differential operator.
The first servo driver controls the first servo motor to track the rotating speed command omega in The first bidirectional fixed displacement hydraulic pump 3 is driven to supply oil to the first hydraulic cylinder, and the movement of the first hydraulic cylinder is controlled.
Converting the pitch angle command signal into a displacement signal of a first hydraulic cylinder, and controlling the displacement of a hydraulic cylinder piston rod of the pitch system, wherein a calculation model of the displacement command signal of the first hydraulic cylinder is as follows:
Wherein: l (L) in Representing a first hydraulic cylinder displacement command signal; r represents the turning radius of the end part of the piston rod of the first hydraulic cylinder; h represents the distance from the first cylinder mounting hinge to the center of the vane; alpha represents an included angle between the turning radius of the piston rod end part of the first hydraulic cylinder and the connecting line of the first hydraulic cylinder mounting hinge to the center of the blade when the pitch angle is 0 degrees; l (L) min The distance from the end of the piston rod to the first cylinder mounting hinge position at the 0 pitch angle position is indicated.
The pitch controller commands the pitch angle of the main control system to be beta in Is converted into a displacement command signal l of a first hydraulic cylinder in And designing a control link of the first EHA driving unit A to realize the motion control of the first hydraulic cylinder.
S4: and establishing a control link of the second EHA driving unit B according to the pitch load predicted value and the speed error feedback signal of the first EHA driving unit A.
Design feedforward control link C 5 (s) realizing the driving force instruction F for the second hydraulic cylinder in Is a fast track of (2); second hydraulic cylinder driving force command signal F in With the second cylinder driving force feedback signal p B K 3 And comparing to obtain a second hydraulic cylinder driving force difference value, wherein the second hydraulic cylinder driving force difference value is as follows:
e f ＝F in -p B K 1 ；
wherein: e, e f Representing a driving force difference value of the second hydraulic cylinder; f (F) in A driving force command signal indicating a driving force of the second hydraulic cylinder; p is p B Representing the high pressure chamber pressure of the second hydraulic cylinder; k (K) 1 Representing the feedback coefficient.
Design error compensation controller C 4 (s) compensating for the error, eliminating steady state error; and simultaneously, the variable pitch controller feeds back a difference value according to the speed of the first hydraulic cylinder, as follows:
e v ＝l in s-ls；
wherein: e, e v Representing a speed feedback difference value of the variable pitch controller according to the first hydraulic cylinder; s denotes a differential operator.
Design feedforward compensation controller C 6 (s) performing velocity compensation.
Adding the three control links to obtain a torque control instruction T of a second servo motor in the second EHA driving unit A in The following is shown:
T in (s)＝e f C 4 (s)+F in C 5 (s)+e v C 6 (s)；
wherein: t (T) in (s) represents a torque control instruction of the second servo motor in the second EHA drive unit B; c (C) 4 (s) represents a second error compensation control section; c (C) 5 (s) represents a fifth feedforward compensation control component; c (C) 6 (s) represents a sixth feedforward compensation control section.
The second servo driver controls the second servo motor torque tracking torque command T in Driving a second bidirectional fixed displacement hydraulic pump to supply power for a second hydraulic cylinderThe oil causes the second hydraulic cylinder to generate a driving force.
The pitch controller predicts a pitch load predictive value T Znorm Converted into a driving force command F of a second hydraulic cylinder in The relationship between the two is as follows:
wherein: f (F) in Representing a second hydraulic cylinder driving force command parameter; t (T) Znorm And representing the predicted value of the variable pitch load of the unit.
S5: the first EHA driving unit A and the second EHA driving unit B are cooperatively controlled, so that cooperative control of the double EHA driving units is realized.
And (3) acquiring the first EHA driving unit A and the second EHA driving unit B in the S3 and the S4 to cooperatively drive the blades to change the pitch, so as to realize dynamic high-precision tracking of the pitch angle instruction of the main control system by the dual-EHA driving independent pitch-changing system, and finally realize cooperative control of the dual-EHA driving unit. Fig. 5 is a flowchart of a method for switching control modes of a pitch system according to an embodiment of the present invention.
FIG. 6 is a schematic diagram of a control system of a pitch cooperative control method according to an embodiment of the present invention; table 1 shows the efficiency comparison data of the EHA driving variable pitch system and the valve control cylinder variable pitch system realized by the control principle of the method, and the system efficiency of the method can be obviously higher than that of the valve control cylinder variable pitch system.
Table 1 efficiency comparison of EHA driven pitch and valve controlled cylinder pitch systems
| EHA driving variable pitch | Valve control cylinder variable pitch | |
| System efficiency | ≈60％ | ≤38.5％ |
The second aspect of the present invention provides a pitch control system of a pitch cooperative control method of a dual EHA driven independent pitch system, capable of implementing cooperative control of the dual EHA driven independent pitch system, and the pitch control system mainly includes: the wind turbine generator system main control system 23, the pitch controller 22, the first EHA driving unit A, the second EHA driving unit B and the pitch bearing 10.
The wind turbine main control system 23 is mainly used for detecting and controlling the complete machine state of the wind turbine, and controlling the pitch system by combining the running state of the wind turbine and the wind condition.
The pitch controller 22 converts a pitch angle instruction of the main control system 23 into a rotating speed instruction of the first servo motor 2 of the first EHA driving unit A, and combines predicted pitch load and hydraulic cylinder two-cavity pressure feedback to set a torque instruction of the servo motor B of the second EHA driving unit B; fig. 3 is a schematic structural diagram of a pitch actuator according to an embodiment of the present invention. The pitch controller 22 performs position control and pressure control on the first EHA driving unit a and the second EHA driving unit B, respectively, so as to realize dynamic high-precision tracking of pitch angle instructions of the main control system 23 by the dual EHA driving independent pitch system. Fig. 4 is a schematic structural diagram of a hydraulic rod of a pitch actuator according to an embodiment of the present invention.
The first EHA drive unit a includes a first servo driver 1, a first servo motor 2, a first bidirectional fixed displacement pump 3, a first pilot operated check valve 4, a second pilot operated check valve 20, a first relief valve 5, a second relief valve 19, a first electromagnetic switching valve 6, a second electromagnetic switching valve 7, a third electromagnetic switching valve 14, a fourth electromagnetic switching valve 15, a fifth electromagnetic switching valve 16, a sixth electromagnetic switching valve 18, a first closed tank 13, a first emergency accumulator 17, a first hydraulic cylinder 11, a first displacement sensor 8, a first rodless cavity pressure sensor 12, and a first rodless cavity pressure sensor 21. The first servo driver 1 is connected with the first servo motor 2 and controls the rotating speed and the torque of the first servo motor 2; the first servo motor 2 is coaxially connected with the first bidirectional fixed displacement pump 3; the P port of the first bidirectional fixed displacement pump 3 is respectively connected with the P port of the fifth electromagnetic switch valve 16, the P port of the sixth electromagnetic switch valve 18, the Q port of the second overflow valve 19, the Q port of the second hydraulic control one-way valve 20 and the control oil port of the first hydraulic control one-way valve 4; the Q port of the bidirectional fixed displacement pump 3 is respectively connected with the P port of the first electromagnetic switch valve 6, the P port of the second overflow valve 19, the Q port of the first hydraulic control one-way valve 4 and the control oil port of the second hydraulic control one-way valve 20; the P port of the first hydraulic control one-way valve 4 is respectively connected with the Q port of the first overflow valve 5, the P port of the second electromagnetic switch valve 7, the oil port of the first closed oil tank 13, the P port of the third electromagnetic switch valve 14, the Q port of the second overflow valve 19 and the P port of the second hydraulic control one-way valve 20; the P port of the fourth electromagnetic switch valve 15 is respectively connected with the oil port of the first emergency accumulator 17 and the Q port of the sixth electromagnetic switch valve 18; the rodless cavity of the first hydraulic cylinder 11 is respectively connected with the first rodless cavity pressure sensor 12, the Q port of the third electromagnetic switch valve 14, the Q port of the fourth electromagnetic switch valve 15 and the Q port of the fifth electromagnetic switch valve 16; the rod cavity of the first hydraulic cylinder 11 is respectively connected with the Q port of the first electromagnetic switch valve 6, the P port of the second electromagnetic switch valve 7 and the first rod cavity pressure sensor 21; the first displacement sensor 8 is mounted on the first hydraulic cylinder 11 for monitoring the displacement of the piston rod of the hydraulic cylinder 11. The second EHA drive unit B includes a second servo driver 24, a second servo motor 25, a second bi-directional fixed displacement pump 26, a third pilot operated check valve 27, a fourth pilot operated check valve 42, a third relief valve 28, a fourth relief valve 41, a seventh electromagnetic switching valve 29, an eighth electromagnetic switching valve 30, a ninth electromagnetic switching valve 36, a tenth electromagnetic switching valve 37, an eleventh electromagnetic switching valve 38, a twelfth electromagnetic switching valve 40, a second closed tank 35, a second emergency accumulator 39, a second hydraulic cylinder 33, a second displacement sensor 32, a second rodless cavity pressure sensor 34, and a second rod cavity pressure sensor 31.
The second servo driver 24 is connected with the second servo motor 25 and controls the rotating speed and the torque of the second servo motor 25; the second servo motor 25 is coaxially connected with a second bidirectional constant displacement pump 26; the P port of the second bidirectional displacement pump 26 is respectively connected with the P port of the eleventh electromagnetic switch valve 38, the P port of the twelfth electromagnetic switch valve 40, the Q port of the fourth overflow valve 41, the Q port of the fourth hydraulic control one-way valve 42 and the control oil port of the third hydraulic control one-way valve 27; the Q port of the second bidirectional constant displacement pump 26 is respectively connected with the P port of the seventh electromagnetic switch valve 29, the P port of the fourth overflow valve 41, the Q port of the third hydraulic control one-way valve 27 and the control oil port of the fourth hydraulic control one-way valve 42; the port P of the third hydraulic control one-way valve 27 is respectively connected with the port Q of the third overflow valve 28, the port P of the eighth electromagnetic switch valve 30, the oil port of the second closed oil tank 35, the port P of the ninth electromagnetic switch valve 36, the port Q of the fourth overflow valve 41 and the port P of the fourth hydraulic control one-way valve 42; the P port of the tenth electromagnetic switch valve 37 is respectively connected with the oil port of the second emergency accumulator 39 and the Q port of the twelfth electromagnetic switch valve 40; the rodless cavity of the second hydraulic cylinder 33 is respectively connected with the second rodless cavity pressure sensor 34, the Q port of the ninth electromagnetic switch valve 36, the Q port of the tenth electromagnetic switch valve 37 and the Q port of the eleventh electromagnetic switch valve 38; the rod cavity of the second hydraulic cylinder 33 is respectively connected with the Q port of the seventh electromagnetic switch valve 29, the P port of the eighth electromagnetic switch valve 30 and the second rod cavity pressure sensor 31; a second displacement sensor 32 is mounted on the second hydraulic cylinder 33 for monitoring the displacement of the piston rod of the second hydraulic cylinder 33.
The outer ring of the variable-pitch bearing 10 is fixed on the hub 43, the inner ring of the variable-pitch bearing 10 is fixedly connected with the root of the blade 44 and the torque transmission disc 9, the first hydraulic cylinder 11 and the second hydraulic cylinder 33 are arranged in parallel and oppositely, the tail parts of rod cavities of the first hydraulic cylinder 11 and the second hydraulic cylinder 33 are respectively connected with the hub 43 through hinges, and the end parts of piston rods of the first hydraulic cylinder 11 and the second hydraulic cylinder 33 are respectively connected with the torque transmission disc 9 through joint bearings.
In conclusion, the prediction result of the variable pitch cooperative control method of the dual EHA driving independent variable pitch system proves that the method has a good effect.
(1) The double EHA driving independent variable pitch system adopted by the embodiment of the invention comprises two EHA driving units, and the highly integrated closed pump control hydraulic system (EHA) driving units do not need a hydraulic slip ring and a long pipeline, so that the risk of oil leakage is reduced, and the maintenance is convenient and fast; the two EHA driving units are arranged in parallel and opposite, cooperatively drive the blades to change the pitch, and have large driving force and small radial unbalanced load.
(2) According to the embodiment of the invention, the high-precision control and the pressure compensation control of the position of the first EHA driving unit and the second EHA driving unit are respectively carried out through the pitch load prediction, so that the high-precision and high-dynamic tracking of the pitch angle instruction of the main control system by the dual-EHA driving independent pitch system can be realized.
(3) Compared with the efficiency of the valve control cylinder variable pitch system, the embodiment of the invention can obviously show that the efficiency of the application system of the method is higher than that of the valve control cylinder variable pitch system.
The above examples are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solution of the present invention should fall within the scope of protection defined by the claims of the present invention without departing from the spirit of the present invention.
Claims (5)
1. The pitch cooperative control method of the double EHA driving independent pitch system is characterized by comprising the following steps of:
step 1: based on wind field SCADA and wind turbine generator set data, establishing a variable pitch system load and unit power prediction model;
acquiring long-term SCADA data and wind turbine generator system data in a wind field, cleaning the data, and carrying out normalization processing to obtain a normalization result x of a state quantity and a normalization result y of an actual quantity; taking the normalization result x= { v, w, θ, β, Δψ } of the state quantity as the input of the neural network, the normalization result y= { P, T of the actual quantity Z And (2) outputting the model as a neural network, and training a variable-pitch system load and unit power prediction model through an artificial neural network to obtain the variable-pitch system load and unit power prediction model, wherein the variable-pitch system load and unit power prediction model is as follows:
Wherein: t (T) Z Representing an actual value of pitch load; p represents the actual value of the unit power; x=[ v, w, θ, β, Δψ ] represents the normalization result of the state quantity; v represents the wind wheel plane wind speed; w represents the rotational speed of the wind wheel; θ represents the blade azimuth angle; beta represents the blade pitch angle; Δψ represents yaw angle error; f (f) 1 Representing a variable pitch load neural network model; f (f) 2 Representing a power neural network model of the unit;
step 2: obtaining a predicted value of the variable-pitch load of the unit and the unit power by using a variable-pitch load and unit power prediction model;
the state quantity x= { v, w, θ, β, Δψ } which is monitored and collected by the unit main control system in real time; substituting the normalized state quantity into a unit variable pitch load model and a unit power prediction model to obtain a unit variable pitch load and a unit power prediction value of T Znorm ，P norm Then, the inverse normalization treatment is carried out, and the treatment process is as follows:
wherein: y represents the normalization result of the actual quantity; y is norm Representing a predicted value of the variable pitch load of the unit; y is max Representing a predicted value of the unit power; y is min A minimum value representing the actual quantity;
step 3: establishing a control link of the first EHA driving unit according to the pitch angle instruction and the pitch load predicted value;
converting the pitch angle command signal into a displacement signal of a first hydraulic cylinder, and controlling the displacement of a hydraulic cylinder piston rod of the pitch system, wherein a calculation model of the displacement command signal of the first hydraulic cylinder is as follows:
Wherein: l (L) in Representing a first hydraulic cylinder displacement command signal; r represents the turning radius of the end part of the piston rod of the first hydraulic cylinder; h represents the distance from the first cylinder mounting hinge to the center of the vane; alpha represents half of the revolution of the piston rod end of the first hydraulic cylinder when the pitch angle is 0 DEGAn included angle between the diameter and the connecting line of the first hydraulic cylinder mounting hinge to the center of the blade; l (L) min The distance from the end of the piston rod to the position of the first hydraulic cylinder mounting hinge when the pitch angle is 0 degrees is represented;
the pitch controller commands the pitch angle of the main control system to be beta in Is converted into a displacement command signal l of a first hydraulic cylinder in Designing a control link of the first EHA driving unit to realize the motion control of the first hydraulic cylinder;
step 4: establishing a control link of a second EHA driving unit according to the pitch load predicted value and a speed error feedback signal of the first EHA driving unit;
the pitch controller predicts a pitch load predictive value T Znorm Converted into a second hydraulic cylinder driving force command F in The relationship between the two is as follows:
wherein: f (F) in Representing a second hydraulic cylinder driving force command parameter; t (T) Znorm Representing a predicted value of the variable pitch load of the unit;
step 5: the first EHA driving unit and the second EHA driving unit are cooperatively controlled to realize cooperative control of the double EHA driving units;
And (3) acquiring dynamic high-precision tracking of pitch angle instructions of the main control system by the dual-EHA driving independent pitch system by cooperatively driving the blades by the first EHA driving unit and the second EHA driving unit in the step (3) and the step (4), and finally, cooperatively controlling the dual-EHA driving unit.
2. The method for controlling the pitch of the dual EHA driven independent pitch system according to claim 1, wherein the step 1 is characterized in that long-term SCADA data and wind turbine generator system data in a wind field are obtained, data are cleaned, and normalization processing is performed, specifically:
the content of the long-term SCADA data and the wind turbine group data in the wind field covers v under all wind conditions in ≤v≤v out Operating state data v of (v) in Represents cut-in wind speed, v out Indicating the cut-out wind speed;
the data are cleaned to remove the data of the shutdown state of the unit, the acquisition errors of the sensor and the interference;
long-term SCADA data and wind turbine group data in a wind field are acquired, cleaning data are subjected to normalization processing, and the processing procedure is as follows:
wherein: x is x norm A normalization result representing the state quantity; x is x s An input value representing a state quantity; x is x min Representing a minimum value of the state quantity; x is x max A maximum value representing a state quantity; y represents an input value of the actual quantity; y is norm A normalization result representing the actual quantity; y is max A maximum value representing the actual amount; x= { v, w, θ, β, Δψ } includes the rotor plane wind speed v, rotor speed w, blade azimuth angle θ, blade pitch angle β, and yaw angle error Δψ.
3. The method for controlling the pitch cooperation of the dual EHA driven independent pitch system according to claim 1, wherein the step 3 establishes a control link of the first EHA driving unit according to the pitch angle command and the pitch load prediction value, specifically:
design feedforward control link C 2 (s) realizing the displacement command l of the first hydraulic cylinder in Is a fast track of (2); the first hydraulic cylinder displacement command signal l in And comparing the displacement feedback signal with the displacement feedback signal l of the first hydraulic cylinder to obtain a displacement difference value of the first hydraulic cylinder, wherein the displacement difference value is as follows:
e l ＝l in -l；
wherein: e, e l Representing a first hydraulic cylinder displacement difference; l represents a first hydraulic cylinder displacement feedback signal;
design error compensation controller C 1 (s) compensating for the error, eliminating steady state error;
according to the predicted value T of the variable pitch load Z Design feedforward compensation control C 3 (s) compensating;
adding the three control links to obtain a rotation speed control instruction omega of the servo motor in the first EHA driving unit in The following is shown:
ω in (s)＝e l C 1 (s)+l in C 2 (s)+F z C 3 (s)；
Wherein: omega in (s) represents a rotational speed control instruction of the servo motor in the first EHA drive unit; c (C) 1 (s) represents a first error compensation control section; c (C) 2 (s) represents a second feedforward control component; c (C) 3 (s) represents a third feedforward compensation control component; f (F) z Representing feedback parameters of a third feedforward compensation control link; s represents a differential operator;
servo driver for controlling servo motor rotation speed to track rotation speed command omega in The bidirectional fixed displacement hydraulic pump is driven to supply oil to the first hydraulic cylinder, and the first hydraulic cylinder is controlled to move.
4. The method for controlling the pitch co-operation of the dual EHA driven independent pitch system according to claim 1, wherein the step 4 establishes a control link of the second EHA driving unit according to the pitch load predicted value and the speed error feedback signal of the first EHA driving unit, specifically:
design feedforward control link C 5 (s) realizing the driving force instruction F for the second hydraulic cylinder in Is a fast track of (2); second hydraulic cylinder driving force command signal F in With the second cylinder driving force feedback signal p B K 3 And comparing to obtain a second hydraulic cylinder driving force difference value, wherein the second hydraulic cylinder driving force difference value is as follows:
e f ＝F in -p B K 1 ；
wherein: e, e f Representing a second hydraulic cylinder drive force difference; f (F) in A second hydraulic cylinder driving force instruction signal; p is p B Representing the high pressure chamber pressure of the second hydraulic cylinder; k (K) 1 Representing the feedback coefficient;
design error compensation controller C 4 (s) error is performedCompensating, namely eliminating steady-state errors; and simultaneously, the variable pitch controller feeds back a difference value according to the speed of the first hydraulic cylinder, as follows:
e v ＝l in s-ls；
wherein: e, e v Representing a speed feedback difference value of the variable pitch controller according to the first hydraulic cylinder; s represents a differential operator;
design feedforward compensation controller C 6 (s) performing a velocity compensation;
adding the three control links to obtain a torque control instruction T of the servo motor in the second EHA driving unit in As shown below;
T in (s)＝e f C 4 (s)+F in C 5 (s)+e v C 6 (s)；
wherein: t (T) in (s) represents a torque control command of the servo motor in the second EHA drive unit; c (C) 4 (s) represents a second error compensation control section; c (C) 5 (s) represents a fifth feedforward compensation control component; c (C) 6 (s) represents a sixth feedforward compensation control step;
servo driver control servo motor torque tracking torque command T in The bidirectional fixed displacement hydraulic pump is driven to supply oil to the second hydraulic cylinder, so that the second hydraulic cylinder generates driving force.
5. A pitch system for implementing a pitch cooperative control method of a dual EHA driven independent pitch system according to any one of claims 1 to 4, characterized in that: can realize the independent system cooperative control that becomes of two EHA drive, become the oar system and include: the wind turbine generator system comprises a wind turbine generator system main control system, a variable pitch controller, a first EHA driving unit, a second EHA driving unit and a variable pitch bearing;
The main control system of the wind turbine is mainly used for detecting and controlling the state of the whole wind turbine, and controlling the pitch system by combining the running state of the wind turbine and the wind condition;
the pitch angle command of the main control system is converted into a rotating speed command of a first servo motor of the first EHA driving unit by the pitch controller, and a torque command of a servo motor of the second EHA driving unit is set by combining the predicted pitch load and the pressure feedback of two cavities of the hydraulic cylinder; the variable pitch controller respectively performs position control and pressure control on the first EHA driving unit and the second EHA driving unit, so that the dynamic tracking of the pitch angle instruction of the main control system by the dual-EHA driving independent variable pitch system is realized;
the first EHA driving unit comprises a first servo driver, a first servo motor, a first bidirectional fixed displacement pump, a first hydraulic control one-way valve, a second hydraulic control one-way valve, a first overflow valve, a second overflow valve, a first electromagnetic switch valve, a second electromagnetic switch valve, a third electromagnetic switch valve, a fourth electromagnetic switch valve, a fifth electromagnetic switch valve, a sixth electromagnetic switch valve, a first closed oil tank, a first emergency energy accumulator, a first hydraulic cylinder, a first displacement sensor, a first rodless cavity pressure sensor and a first rod cavity pressure sensor; the first servo driver is connected with the first servo motor and controls the rotating speed and the torque of the first servo motor; the first servo motor is coaxially connected with the first bidirectional fixed displacement pump; the P port of the first bidirectional fixed displacement pump is respectively connected with the P port of the fifth electromagnetic switch valve, the P port of the sixth electromagnetic switch valve, the Q port of the second overflow valve, the Q port of the second hydraulic control one-way valve and the control oil port of the first hydraulic control one-way valve; the Q port of the bidirectional fixed displacement pump is respectively connected with the P port of the first electromagnetic switch valve, the P port of the second overflow valve, the Q port of the first hydraulic control one-way valve and the control oil port of the second hydraulic control one-way valve; the P port of the first hydraulic control one-way valve is respectively connected with the Q port of the first overflow valve, the P port of the second electromagnetic switch valve, the oil port of the first closed oil tank, the P port of the third electromagnetic switch valve, the Q port of the second overflow valve and the P port of the second hydraulic control one-way valve; the P port of the fourth electromagnetic switch valve is respectively connected with the oil port of the first emergency accumulator and the Q port of the sixth electromagnetic switch valve; the rodless cavity of the first hydraulic cylinder is connected with the first rodless cavity pressure sensor, the Q port of the third electromagnetic switch valve, the Q port of the fourth electromagnetic switch valve and the Q port of the fifth electromagnetic switch valve respectively; the rod cavity of the first hydraulic cylinder is respectively connected with the Q port of the first electromagnetic switch valve, the P port of the second electromagnetic switch valve and the first rod cavity pressure sensor; the first displacement sensor is arranged on the first hydraulic cylinder and used for monitoring the displacement of a piston rod of the hydraulic cylinder; the second EHA driving unit comprises a second servo driver, a second servo motor, a second bidirectional fixed displacement pump, a third hydraulic control one-way valve, a fourth hydraulic control one-way valve, a third overflow valve, a fourth overflow valve, a seventh electromagnetic switch valve, an eighth electromagnetic switch valve, a ninth electromagnetic switch valve, a tenth electromagnetic switch valve, an eleventh electromagnetic switch valve, a twelfth electromagnetic switch valve, a second closed oil tank, a second emergency accumulator, a second hydraulic cylinder, a second displacement sensor, a second rodless cavity pressure sensor and a second rod cavity pressure sensor;
The second servo driver is connected with the second servo motor and controls the rotating speed and the torque of the second servo motor; the second servo motor is coaxially connected with the second bidirectional constant displacement pump; the P port of the second bidirectional constant displacement pump is respectively connected with the P port of the eleventh electromagnetic switch valve, the P port of the twelfth electromagnetic switch valve, the Q port of the fourth overflow valve, the Q port of the fourth hydraulic control one-way valve and the control oil port of the third hydraulic control one-way valve; the Q port of the second bidirectional constant displacement pump is respectively connected with the P port of the seventh electromagnetic switch valve, the P port of the fourth overflow valve, the Q port of the third hydraulic control one-way valve and the control oil port of the fourth hydraulic control one-way valve; the P port of the third hydraulic control one-way valve is respectively connected with the Q port of the third overflow valve, the P port of the eighth electromagnetic switch valve, the oil port of the second closed oil tank, the P port of the ninth electromagnetic switch valve, the Q port of the fourth overflow valve and the P port of the fourth hydraulic control one-way valve; the P port of the tenth electromagnetic switch valve is respectively connected with the oil port of the second emergency accumulator and the Q port of the twelfth electromagnetic switch valve; the rodless cavity of the second hydraulic cylinder is respectively connected with the second rodless cavity pressure sensor, the Q port of the ninth electromagnetic switch valve, the Q port of the tenth electromagnetic switch valve and the Q port of the eleventh electromagnetic switch valve; the rod cavity of the second hydraulic cylinder is respectively connected with the Q port of the seventh electromagnetic switch valve, the port of the eighth electromagnetic switch valve and the second rod cavity pressure sensor; the second displacement sensor is arranged on the second hydraulic cylinder and is used for monitoring the displacement of a piston rod of the second hydraulic cylinder;
The variable-pitch bearing outer ring is fixed on the hub, the variable-pitch bearing inner ring is fixedly connected with the root of the blade and the torque transmission disc, the first hydraulic cylinder and the second hydraulic cylinder are arranged in parallel and opposite, the tail parts of rod cavities of the first hydraulic cylinder and the second hydraulic cylinder are respectively connected with the hub through hinges, and the end parts of piston rods of the first hydraulic cylinder and the second hydraulic cylinder are respectively connected with the torque transmission disc through joint bearings.
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