Wind turbine pitch control system

Abstract

The present invention discloses a wind turbine pitch control system, which relates to the technical field of wind power generation, and in particular to a wind turbine pitch control system. The device includes a pitch hydraulic system, a controller, a calibration switch, a calibration block, a grating encoder, and a three-position four-way solenoid valve. The pitch control system controls the pitch hydraulic system actuator through the three-position four-way valve to achieve pitch action. The pitch control system is also provided with a grating encoder, which is used to collect pitch rotation angle information. The grating encoder has a high density of collected rotation signals and a high collection accuracy, thereby achieving more accurate control accuracy. The calibration switch is used to determine a predetermined position to prevent abnormal conditions such as controller reset, temporary freeze, or interference between the grating encoder and the controller during signal transmission, thereby causing the absolute angle obtained by the controller to be inaccurate.

Description

Technical Field

[0001] The invention relates to the technical field of wind power generation, and in particular to a variable pitch control system for a wind power generator set. Background Art

[0002] The wind turbine pitch system is used to adjust the blade pitch angle so that the wind turbine can be in the best working state. It is also an important part of the safety system on the wind turbine, which can ensure that the wind turbine can start and stop normally and shut down in emergency under special circumstances. About 70% of the working time of the wind turbine is in small pitch angle, which requires the pitch system to have high precision and short pitch mechanism execution stroke; about 30% of the working time of the wind turbine is in large pitch angle, which requires the pitch system to respond quickly and the pitch mechanism to have a long execution stroke.

[0003] Modern wind turbines (doubly fed, direct drive, semi-direct drive) almost all use variable pitch wind turbines. Variable pitch means that the vertical projection of the blade changes. Simply put, when the blade is vertical to the ground, it is 0°, and when it is horizontal, it is 90°. 90° to 0° is called open pitch, and the opposite is called feathering.

[0004] The output power of the wind turbine increases with the increase of wind speed. When the wind speed is too high, if the wind turbine blades are not retracted, the load on the entire wind turbine will be very large. The most serious accident is the tower collapse. The blades are fully unfolded when the wind speed is around 3-8 meters per second; when the wind speed exceeds 8 meters per second (some units may be around 10 meters per second), the blades begin to change pitch. When the blades are aligned, the overall blade force is reduced, and the wind turbine load is also reduced, but the output power will not decrease due to the wind speed, so the rated output power can be guaranteed under the premise of ensuring the safety of the unit. Most wind turbines will fully feather the blades when the wind speed exceeds 20 meters per second. At the same time, the wind turbine stops running and yaws to ensure the minimum load on the unit.

[0005] In the prior art, the pitch control system either adopts a hydraulic pitch control method, a control method in which all blades change pitch simultaneously, or a control method in which each blade changes pitch independently. The independent pitch control method is becoming more and more popular because it can make corresponding adjustments in a timely manner according to the uniformity of the wind field and the handling of the wind turbine.

[0006] In the implementation of independent pitch control, the driving wheel is usually externally toothed, the pitch bearing is internally toothed, and the blades are fixed to the pitch bearing by bolts, hubs, and pitch bearings. During the installation and use of independent pitch control, the pitch mechanism will cause inconsistencies in the pitch angles of each independent blade due to various usage factors. Over time, this will cause the wind turbine to vibrate, abnormal wear of the bearings of the turbine, and even damage to the turbine. As for the accuracy of pitch angle adjustment, the general method is currently manual regular inspection and maintenance, which requires a lot of manpower and material resources, and because the wind turbine is installed at a high position, it brings certain inconveniences and safety issues to the operation. Summary of the invention

[0007] The invention provides a wind turbine generator set pitch control system, which is used to solve the problem that manual adjustment of pitch accuracy is time-consuming and labor-intensive.

[0008] The present invention adopts the following technical solution:

[0009] A wind turbine generator set pitch control system, comprising: a pitch hydraulic system, a controller, a calibration switch, a calibration block, a grating encoder and a three-position four-way solenoid valve;

[0010] The wind turbine generator set is provided with a variable pitch bearing, the variable pitch bearing comprises a moving ring and a stationary ring, the calibration switch is arranged on the stationary ring, the calibration block is arranged on the moving ring, the calibration switch is used to collect predetermined variable pitch angle information, the grating encoder is used to collect the hub rotation information, the three-position four-way valve is used to control the variable pitch hydraulic system to implement the variable pitch action; the controller is used to receive the predetermined variable pitch angle information and the hub rotation information, and the controller is also used to control the three-position four-way valve to implement the variable pitch action through the variable pitch hydraulic system;

[0011] The calibration switch, the grating encoder and the three-position four-way solenoid valve are electrically connected to the controller respectively.

[0012] Furthermore, the moving coil is provided with a slide groove and a fixing screw, the slide groove is fixedly connected to the moving coil, the calibration block is slidably connected to the slide groove, and the fixing screw is used to fix the calibration block on the slide groove.

[0013] Furthermore, it also includes: a GPRS communication module and a server, the server is used to monitor the pitch angle information, the server is also used to issue pitch angle instructions to the controller, the GPRS communication module is used to establish a communication connection between the controller and the server, and the GPRS communication module is respectively communicated with the controller and the server.

[0014] Furthermore, it also includes: an acceleration sensor, which is fixedly connected to the wind turbine generator set, and is used to collect vibration information of the wind turbine generator set. The controller is also used to transmit the received vibration information of the wind turbine generator set to the server through the GPRS communication module, and the acceleration sensor is electrically connected to the controller.

[0015] Furthermore, it also includes an electric motor and a pressure gauge. The pitch hydraulic system is provided with an accumulator. The electric motor is used to provide kinetic energy for the pitch hydraulic control system. The pressure gauge is used to collect the pressure of the pitch hydraulic system. The controller is also used to control the start or stop of the motor when the pressure of the pitch hydraulic system reaches a threshold value. The pressure gauge and the motor are electrically connected to the controller respectively.

[0016] Furthermore, it also includes a super capacitor, which is used to provide electrical energy to the controller, the GPRS communication module and the motor.

[0017] Furthermore, the calibration switch is a Hall switch, and the calibration block is a magnet.

[0018] The positive effects of the present invention are as follows:

[0019] A variable pitch control system for a wind turbine generator set, the variable pitch control system controls the variable pitch hydraulic system actuator through a three-position four-way valve to achieve variable pitch action, the control method is simple and reliable, for the three-position four-way valve with an O-shaped middle position function, the middle position function can lock the blades after the pitch is changed. The variable pitch control system is also provided with a grating encoder, the grating encoder is used to collect variable pitch rotation angle information, the grating encoder collects rotation signal density with high, usually can achieve a rotation of one circle to send thousands of signals, so the collection accuracy is high, thereby achieving more precise control accuracy. The calibration switch is used to determine the predetermined position to prevent abnormal conditions such as controller reset, temporary freeze or interference between the grating encoder and the controller during signal transmission, thereby causing the absolute angle obtained by the controller to be inaccurate.

[0020] The calibration block of the pitch control system is slidably connected to the moving coil through a slide groove. When the pitch system needs to be adjusted, only the relative position of the calibration block and the moving coil needs to be adjusted. Compared with the mechanical adjustment of the pitch system in the prior art, the adjustment is more labor-saving, efficient and accurate.

[0021] The wind turbine pitch control system is also equipped with a server and a GPRS module. The staff can remotely monitor the pitch angle information of the wind turbine. They can also send remote control instructions to the controller through the server and the GPRS module, requiring the wind turbine to change the pitch according to the angle specified by the instruction. This allows them to cope with sudden severe weather, emergency maintenance, and emergency testing without having to go to the wind turbine site to perform operations.

[0022] The acceleration sensor is used to collect vibration information of the wind turbine generator set. This information is sent to the controller. When the vibration information exceeds the threshold, the controller controls the pitch system to perform pitch-changing action to avoid unnecessary losses. The vibration information is also sent to the server through the GPRS module. When the server staff receives the information, they will conduct a simple analysis and judgment. If necessary, they will send personnel to investigate the root cause of the vibration on site. Once the cause of the problem is determined, they will also solve the problem.

[0023] The variable pitch hydraulic system is equipped with an accumulator, the hydraulic pressure is stable, and the ripple is small. The variable pitch control system controls the motor of the variable pitch hydraulic system to stop the motor when no additional pressure is needed, and unload the motor to prevent the hydraulic oil of the hydraulic system from heating up, aging and deterioration, and save electricity. The accumulator can still provide kinetic energy for variable pitch when the external power supply is stopped.

[0024] The wind turbine pitch control system is also equipped with a supercapacitor, which is used to provide power to the controller, GPRS communication module and motor when the external power supply is cut off. The supercapacitor and accumulator provide double insurance to ensure the safe operation of the equipment in an emergency.

[0025] The calibration switch used to calibrate the reference angle is a Hall switch, and the matching calibration block is a magnet. There is no contact between the calibration block and the calibration switch, so there is no wear and tear, and the service life is long. It is suitable for use in harsh working conditions and outdoor conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the principle of a variable pitch hydraulic system according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of a pitch control system according to an embodiment of the present invention;

[0028] Figure 3 Schematic diagram of a control system according to an embodiment of the present invention.

[0029] In the figure:

[0030] Calibration switch 1;

[0031] Calibration block 2;

[0032] Grating encoder 3;

[0033] Three-position four-way solenoid valve 4;

[0034] Dynamic 5;

[0035] Static circle 6;

[0036] Chute 5-1;

[0037] Set screw 7;

[0038] Electric motor 8;

[0039] Pressure gauge 9;

[0040] Accumulator 10. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific implementation methods described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] like Figure 1-3 As shown, a wind turbine generator set pitch control system includes: a pitch hydraulic system, a controller, a calibration switch 1, a calibration block 2, a grating encoder 3 and a three-position four-way solenoid valve 4;

[0043] The wind turbine generator set is provided with a pitch bearing, the pitch bearing includes a moving ring 5 and a stationary ring 6, the calibration switch 1 is arranged on the stationary ring 6, the calibration block 2 is arranged on the moving ring 5, the calibration switch 1 is used to collect predetermined pitch angle information, the grating encoder 3 is used to collect the hub rotation information, the three-position four-way valve is used to control the pitch hydraulic system to implement the pitch action; the controller is used to receive the predetermined pitch angle information and the hub rotation information, and the controller is also used to control the three-position four-way valve to implement the pitch action through the pitch hydraulic system;

[0044] The calibration switch 1 , the grating encoder 3 and the three-position four-way solenoid valve 4 are electrically connected to the controller respectively.

[0045] More specifically, the blades of the wind turbine are mounted on a hub, and the hub is mounted on the inner ring or outer ring of a pitch bearing. The pitch action of the wind turbine blades is achieved by rotating the pitch bearing. In this embodiment, the hub is fixedly connected to the inner ring of the pitch bearing.

[0046] There are many forms of power sources for the rotation of the inner ring of the variable pitch bearing, such as the combination of an electric motor 8 and a reducer, a hydraulic motor drive, and a hydraulic cylinder drive, etc. The technical solution of this embodiment is a hydraulic motor or hydraulic cylinder drive. The power output end of the hydraulic motor or hydraulic cylinder drives the inner ring of the variable pitch bearing to rotate, thereby realizing the variable pitch action.

[0047] For a hydraulic motor or hydraulic cylinder, there are usually two oil ports, which are inlet and outlet ports of each other and correspond to actions in two relative directions respectively. The three-position four-way valve has the control capability of actions in two directions. The three-position four-way valve has two working ports, namely working port A and working port B. Working port A is connected to the first oil port of the hydraulic cylinder or hydraulic motor, and working port B is connected to the second oil port of the hydraulic cylinder or hydraulic motor; the three-position four-way valve also has two system ports, namely pressure port P and oil return port T, which are connected to the hydraulic pressure line and the hydraulic return line respectively.

[0048] When the pressure port P of the three-position four-way valve is connected to the working port A, and the return oil port T is connected to the working port B, the hydraulic motor or hydraulic cylinder implements the action in the first direction. For the hydraulic motor, the hydraulic motor output shaft rotates in the first direction. For the hydraulic cylinder, the cylinder rod performs a push-pull action in the first direction, thereby realizing the pitch change of the blades to the first direction.

[0049] When the pressure port P of the three-position four-way valve is connected to the working port B, and the return oil port T is connected to the working port A, the hydraulic motor or hydraulic cylinder implements the action in the second direction. For the hydraulic motor, the hydraulic motor output shaft rotates in the second direction. For the hydraulic cylinder, the cylinder rod performs a push-pull action in the second direction, thereby realizing the pitch change of the blades to the first direction.

[0050] Obviously, the blade pitch of the wind turbine is continuously variable and can be adjusted to a specified angle according to the wind force. Therefore, a grating encoder 3 is provided on the inner ring or outer ring of the pitch bearing, which is connected to the inner ring or outer ring of the pitch bearing. The grating encoder 3 is used to determine the time when the hydraulic motor or hydraulic cylinder should stop moving by collecting the rotation angle of the inner ring or outer ring. The grating encoder 3 consists of a photoelectric code disk with an axis in the center, on which there are annular open and dark lines. When the disk rotates one pitch, under the illumination of the light-emitting element, the photosensitive element obtains A and B signals as sine waves with a phase difference of 90 degrees. This group of signals is amplified and shaped by the amplifier to obtain an output square wave, A is 90 degrees ahead of B, and its voltage amplitude is generally 5V. If phase A leads phase B, it is positive rotation, and phase B leads phase A, it is negative rotation. The phase relationship between phase A and phase B can be used to distinguish the encoder's positive and reverse rotation. The pulse generated by phase C is the reference pulse, also known as the zero-point pulse. It generates a pulse at a fixed position when the shaft rotates one circle, and the zero reference position of the encoder can be obtained. After the AB phase pulse signal is converted from frequency to voltage, a voltage signal proportional to the shaft speed is obtained, and the speed value and displacement can be measured.

[0051] The rotation angle signal collected by the grating encoder 3 is sent to the controller, and the controller determines the switching timing of the three-position four-way valve according to the angle signal and the predetermined value.

[0052] There are usually two types of grating encoders 3, namely incremental encoders and absolute encoders. As the name implies, incremental encoders can only generate signals of angle rotation and cannot determine the current angle; while absolute encoders can give the absolute value determined by the current encoder. However, in this embodiment, the absolute encoder setting seems to be more suitable. However, due to the poor working environment of the encoder, after multiple runs, the angle obtained is sometimes not correct, or due to some factors, wrong encoding information values ​​appear, such as a short-term freeze in the controller, or interference occurs during signal transmission, resulting in deviations in the measured absolute angle. For wind turbines, this phenomenon is absolutely not allowed to occur, which may cause damage to the unit at the least and major safety accidents at the worst.

[0053] Therefore, as a supplement to the angle measurement value, a calibration switch 1 and a calibration block 2 are provided, and the calibration switch 1 and the calibration block 2 are used to obtain a predetermined angle value, and the angle at which the calibration switch 1 is actuated is the predetermined angle.

[0054] The pitch system is calibrated periodically and when an abnormality occurs, such as when it is reset, through calibration switch 1. The predetermined angle set by calibration switch 1 is usually the feathering angle, that is, the position where the blades are parallel to the ground. When calibration is required, the controller controls the three-position four-way valve to make the hydraulic motor or hydraulic cylinder continuously pitch in the feathering direction. When the predetermined angle is reached, calibration switch 1 moves relative to calibration block 2, and the controller controls the three-position four-way valve to lock the current position as the full feathering angle of the absolute position.

[0055] When changing the pitch, the three-position four-way valve is controlled to change the pitch according to the preset value. During the pitch changing process, the grating encoder 3 continuously gives a rotation angle signal, and the controller accumulates the received rotation signal until it reaches the preset value. The controller controls the three-position four-way valve to stop changing the blade pitch, and the pitch changing ends.

[0056] The variable pitch control system controls the variable pitch hydraulic system actuator through a three-position four-way valve to achieve variable pitch action. The control method is simple and reliable. For a three-position four-way valve with an O-shaped mid-position function, the mid-position function can lock the blades after the variable pitch. The variable pitch control system is also provided with a grating encoder 3, which is used to collect variable pitch rotation angle information. The grating encoder 3 has a high density of collected rotation signals and can usually send thousands of signals per rotation, so the collection accuracy is high, thereby achieving more precise control accuracy. The calibration switch 1 is used to determine the predetermined position to prevent abnormal conditions such as controller reset, temporary freeze, or interference between the grating encoder 3 and the controller during signal transmission, thereby causing the absolute angle obtained by the controller to be inaccurate.

[0057] Furthermore, the moving coil 5 is provided with a slide groove 5-1 and a fixing screw 7, the slide groove 5-1 is fixedly connected to the moving coil 5, the calibration block 2 is slidably connected to the slide groove 5-1, and the fixing screw 7 is used to fix the calibration block 2 on the slide groove 5-1.

[0058] More specifically, after installation, commissioning, or maintenance of a wind turbine, there will usually be a certain deviation in the reference angle. For example, the feathering angle should be the angle at which the blades are parallel to the ground, so that the blades' resistance to the airflow is minimized. If the reference angle deviates, when the wind turbine needs to feather the blades to resist strong winds, the blades' resistance to the airflow will act on the turbine, causing enormous damage.

[0059] Therefore, it is very necessary to adjust the reference angle after installation, commissioning or maintenance.

[0060] The moving coil 5 is a pitch bearing ring connected to the hub. In this embodiment, the hub is the inner ring of the pitch bearing. A slide groove 5-1 is provided on the inner ring. The calibration block 2 is slidably connected to the slide groove 5-1. The set screw 7 is used to fix the calibration block 2 to the slide groove 5-1. When calibration is required, the set screw 7 is loosened, and then the blade is rotated by the pitch system until the blade angle reaches the ideal reference angle, and then the set screw 7 is tightened to lock the calibration block 2.

[0061] The calibration block 2 of the pitch control system is slidably connected to the moving coil 5 through the slide groove 5-1. When the pitch system needs to be adjusted, only the relative position of the calibration block 2 and the moving coil 5 needs to be adjusted. Compared with the mechanical adjustment of the pitch system in the prior art, the adjustment is more labor-saving, efficient and accurate.

[0062] Furthermore, it also includes: a GPRS communication module and a server, the server is used to monitor the pitch angle information, the server is also used to issue pitch angle instructions to the controller, the GPRS communication module is used to establish a communication connection between the controller and the server, and the GPRS communication module is respectively communicated with the controller and the server.

[0063] More specifically, the GPRS module is used to establish a communication connection between the controller and the server. The server is the control core for unified control of multiple wind turbines and the core for recording operation data. For this embodiment, the server is used to detect and record the pitch angle information of the wind turbine, and is also used to issue pitch angle signals. In this embodiment, the GPRS communication module is SIM800C, which is a quad-band GSM / GPRS module. It has stable performance, compact appearance, high cost performance, and can meet the various needs of customers. The operating frequency of SIM800C is GSM / GPRS 850 / 900 / 1800 / 1900MHz, and can realize the transmission of voice, SMS, data and fax information with low power consumption.

[0064] The controller obtains the angle signal through the grating encoder 3 and sends it to the server through the GPRS module at regular intervals. The server displays and records it. The server can also send control instructions to the controller through the GPRS module, requiring the controller to change the pitch according to the angle specified by the instruction. This function is usually used to deal with upcoming bad weather, temporary maintenance, or regular testing.

[0065] The wind turbine pitch control system is also equipped with a server and a GPRS module. The staff can remotely monitor the pitch angle information of the wind turbine. They can also send remote control instructions to the controller through the server and the GPRS module, requiring the wind turbine to change the pitch according to the angle specified by the instruction. This allows them to cope with sudden severe weather, emergency maintenance, and emergency testing without having to go to the wind turbine site to perform operations.

[0066] Furthermore, it also includes: an acceleration sensor, which is fixedly connected to the wind turbine generator set, and is used to collect vibration information of the wind turbine generator set. The controller is also used to transmit the received vibration information of the wind turbine generator set to the server through the GPRS communication module, and the acceleration sensor is electrically connected to the controller.

[0067] More specifically, wind turbines may experience abnormal vibrations due to external influences, such as uneven wind fields, rapid changes in wind direction, or inconsistent blade pitch angles. Such vibrations are very harmful to wind turbines and should be discovered and corrected in a timely manner.

[0068] The acceleration sensor is used to collect vibration information of the wind turbine generator set. This information is sent to the controller. When the vibration information exceeds the threshold, the controller controls the pitch system to perform pitch-changing action to avoid unnecessary losses. The vibration information is also sent to the server through the GPRS module. When the server staff receives the information, they will conduct a simple analysis and judgment. If necessary, they will send personnel to investigate the root cause of the vibration on site. Once the cause of the problem is determined, they will also solve the problem.

[0069] Furthermore, it also includes an electric motor 8 and a pressure gauge 9. The pitch hydraulic system is provided with an accumulator 10. The electric motor 8 is used to provide kinetic energy for the pitch hydraulic control system. The pressure gauge 9 is used to collect the pressure of the pitch hydraulic system. The controller is also used to control the start or stop of the motor 8 when the pressure of the pitch hydraulic system reaches a threshold value. The pressure gauge 9 and the motor 8 are electrically connected to the controller respectively.

[0070] Furthermore, a super capacitor is included, and the super capacitor is used to provide electrical energy to the controller, the GPRS communication module and the motor 8.

[0071] More specifically, the variable pitch hydraulic system is also provided with an accumulator 10 and a pressure gauge 9. The motor 8 is used to provide kinetic energy for the hydraulic system. The motor 8 is controlled by a controller. When the pressure is higher than the pressure threshold of the hydraulic system, the controller controls the motor 8 to stop rotating, and the accumulator 10 provides pressure for the hydraulic system. When the pressure of the hydraulic system is lower than the threshold, the controller controls the motor 8 to start and provide pressure to the accumulator 10 and the hydraulic system.

[0072] The hydraulic system equipped with the accumulator 10 has a stable hydraulic pressure with small ripples, and the motor 8 stops rotating when the pressure is not needed, so that the motor 8 is unloaded, so as to prevent the hydraulic oil of the hydraulic system from heating up, aging and deteriorating, and save electric energy. The accumulator 10 can also provide kinetic energy for the pitch control when the external power supply is stopped.

[0073] The wind turbine pitch control system is also equipped with a supercapacitor, which is used to provide power to the controller, GPRS communication module and motor 8 when the external power supply is cut off. The supercapacitor and the accumulator 10 are double insurances to ensure that the equipment can still operate safely in an emergency.

[0074] Furthermore, the calibration switch 1 is a Hall switch, and the calibration block 2 is a magnet.

[0075] More specifically, the calibration switch 1 is a Hall switch, and the matching calibration block 2 is a magnet. There is no contact between the calibration block 2 and the calibration switch 1, so no wear occurs, the service life is long, and it is suitable for use under harsh working conditions and outdoor conditions.

[0076] The above-described embodiments are only preferred embodiments of the present invention, and are not exhaustive of the feasible implementations of the present invention. For those skilled in the art, any obvious changes made thereto without departing from the principles and spirit of the present invention should be considered to be included in the scope of protection of the claims of the present invention.

Claims

1. A wind turbine generator set pitch control system, comprising: A variable pitch hydraulic system, characterized in that it further comprises: a controller, a calibration switch (1), a calibration block (2), a grating encoder (3) and a three-position four-way solenoid valve (4); the wind turbine generator set is provided with a variable pitch bearing, the variable pitch bearing comprising a moving ring (5) and a stationary ring (6), the calibration switch (1) is arranged on the stationary ring (6), the calibration block (2) is arranged on the moving ring (5), the calibration switch (1) is used to collect predetermined variable pitch angle information, the grating encoder (3) is used to collect hub rotation information, and the three-position four-way valve is used to control the variable pitch hydraulic system to implement a variable pitch action; the controller is used to receive the predetermined variable pitch angle information and the hub rotation information The controller is also used to control the three-position four-way valve to implement the pitch action through the pitch hydraulic system. The calibration switch (1), the grating encoder (3) and the three-position four-way solenoid valve (4) are respectively electrically connected to the controller; the moving coil (5) is provided with a slide groove (5-1) and a set screw (7), the slide groove (5-1) is fixedly connected to the moving coil (5), the calibration block (2) is slidably connected to the slide groove (5-1), and the set screw (7) is used to fasten the calibration block (2) to the slide groove (5-1); the grating encoder (3) has a photoelectric code disk with an axis at the center, and an annular open and dark engraved lines are provided on it.

2. The wind turbine generator set pitch control system according to claim 1, characterized in that: Also includes: A GPRS communication module and a server, wherein the server is used to monitor pitch angle information, and the server is also used to issue pitch angle instructions to the controller. The GPRS communication module is used to establish a communication connection between the controller and the server, and the GPRS communication module is respectively connected to the controller and the server for communication.

3. The wind turbine generator set pitch control system according to claim 2, characterized in that: Also includes: An acceleration sensor is fixedly connected to the wind turbine generator set, and is used to collect vibration information of the wind turbine generator set. The controller is also used to transmit the received vibration information of the wind turbine generator set to the server through the GPRS communication module. The acceleration sensor is electrically connected to the controller.

4. The wind turbine generator set pitch control system according to claim 3, characterized in that: The invention also includes an electric motor (8) and a pressure gauge (9), wherein the pitch hydraulic system is provided with an accumulator (10), the electric motor (8) is used to provide kinetic energy for the pitch hydraulic control system, the pressure gauge (9) is used to collect the pressure of the pitch hydraulic system, and the controller is also used to control the start or stop of the electric motor (8) when the pressure of the pitch hydraulic system reaches a threshold value, and the pressure gauge (9) and the electric motor (8) are respectively electrically connected to the controller.

5. The wind turbine generator set pitch control system according to claim 4, characterized in that: It also includes a super capacitor, which is used to provide electrical energy to the controller, the GPRS communication module and the motor (8).

6. The wind turbine generator set pitch control system according to claim 5, characterized in that: The calibration switch (1) is a Hall switch, and the calibration block (2) is a magnet.

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