Variable pitch mechanism of small wind generating set, control method and wind generating set

Abstract

The invention discloses a variable-pitch mechanism of a small wind generating set, a control method and the wind generating set, the variable-pitch mechanism comprises a generator, a hub and blades rotationally connected to the hub, and a variable-pitch reduction gearbox device or a worm and gear reducer is arranged at the end, away from the hub, of the generator; the output end of the variable pitch reduction gearbox device or the output end of the worm and gear reducer is connected with a ball screw capable of driving the blades to rotate. The output end of the variable-pitch reduction gearbox device or the output end of the worm and gear speed reducer is connected with the ball screw driving the blades to rotate, the crank connecting rod is connected with the blades, the speed reduction effect is achieved, meanwhile, the final speed reduction motion is converted into linear motion of the screw, the synchronous disc is directly pulled to conduct variable-pitch adjustment, the structure is simple, and operation is convenient. In addition, the variable pitch reduction gearbox device or the worm and gear speed reducer can achieve transmission with a large reduction ratio.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wind power generation, more particularly to a variable pitch mechanism of a small wind turbine generator, a control method and a wind turbine generator. BACKGROUND

[0002] Small wind turbines are widely used in remote areas, off-grid power supply, distributed energy systems and other scenarios. Compared with large wind power, small wind power has higher requirements for cost, reliability and maintenance convenience.

[0003] The variable pitch device plays a key role in the variable pitch system of the wind turbine generator. The wind turbine variable pitch device, through the cabin variable pitch mechanism and the hub variable pitch mechanism, enables the wind turbine blades to be pitched and deflected according to the direction and intensity of the wind, so as to maximize the capture of wind energy and convert it into mechanical energy.

[0004] The patent document with publication number CN109469582A discloses a wind turbine generator variable pitch driving mechanism, a variable pitch method and a wind turbine generator. The variable pitch driving mechanism is used for the blades of the wind turbine generator, the root of the blade is connected with a connecting shaft, and a hob is arranged on the connecting shaft; the variable pitch driving mechanism drives the hob through the gear disc to make the blades pitch synchronously; this scheme can control multiple blades to pitch synchronously through the gear disc, omits the structure of the hub of the wind turbine generator, makes the blade mechanism of the wind turbine generator more reasonable, and improves the service life of the wind turbine generator.

[0005] However, it uses more gears, and during the gear transmission process, due to the meshing and friction between the gears, a certain amount of noise and vibration will be generated, which will affect the overall working environment of the wind turbine; and the wind turbine gear transmission device has high process requirements for the manufacturing and installation of the gears, which will affect the stability and efficiency of the transmission. In addition, during the operation of the wind turbine, the gears are prone to wear, corrosion and fracture.

[0006] Early small wind turbines mostly use fixed pitch or mechanical passive variable pitch (such as centrifugal variable pitch), which has low adjustment accuracy and slow response speed, and is difficult to adapt to complex working conditions. With the development of motor control and reducer technology, the electric variable pitch system has become the mainstream. As a core transmission component, the variable pitch reducer needs to convert the high-speed low-torque output of the motor into low-speed high-torque output to drive the rotation of the blades; at the same time, the connection between the variable pitch reducer and the hub variable pitch structure is also a key link to realize accurate adjustment of the pitch angle in the wind turbine generator.

[0007] The current variable pitch reducer for a fan only plays a role of speed reduction output, the existing worm and gear reducer not only plays a role of speed reduction but also can convert rotation into linear motion, multi-stage series can realize large speed reduction ratio, and is relatively space-saving, but defects are that worm and gear transmission is mainly sliding friction, energy loss is large, transmission efficiency is usually only 50-90%, transmission efficiency is lower when self-locking, and worm and gear wear is fast, needs to be replaced regularly, and needs to additionally increase a mounting adapter when being installed with a generator, and cost increase is easily caused. SUMMARY

[0008] The technical problem to be solved by the present application is how to provide a small wind turbine generator variable pitch mechanism capable of realizing large speed reduction ratio and low failure rate.

[0009] The present application solves the above technical problems through the following technical means: the small wind turbine generator variable pitch mechanism comprises a generator, a hub and a blade rotationally connected to the hub, one end of the generator away from the hub is provided with a variable pitch reducer box device or a worm and gear reducer, an output end of the variable pitch reducer box device or the worm and gear reducer is connected with a ball screw capable of driving the blade to rotate, the variable pitch reducer box device comprises a driving motor, a variable pitch reducer box, a screw nut rotationally connected in the variable pitch reducer box, a gear input shaft is rotationally connected in the variable pitch reducer box, the gear input shaft is in transmission connection with an output end of the driving motor, a gear fixedly connected with the gear input shaft is fixedly connected on the screw nut, the screw nut is in screw connection with the ball screw, one end of the ball screw is in transmission connection with the driving motor through a reducer, the other end is in screw connection with a screw assembly nut, a synchronous disc is rotationally connected outside the screw assembly nut, the synchronous disc is in transmission connection with the blade through a crank link, and a limit sensor is further arranged at the one end of the generator away from the hub.

[0010] As a preferred technical scheme, a guide support is fixedly connected on the variable pitch reducer box, a guide key is fixedly connected on the ball screw, a groove matched with the guide key is arranged on the guide support, the guide key is partially inserted into the groove and in sliding connection with the groove, and the limit sensor is fixed on the guide support.

[0011] As a preferred technical scheme, a worm and gear reducer support is fixedly connected at the one end of the generator away from the hub, the worm and gear reducer support is fixedly connected with the worm and gear reducer, a variable pitch motor is fixedly connected on the worm and gear reducer, an output end of the variable pitch motor is in transmission connection with an input end of the worm and gear reducer, and an output end of the worm and gear reducer is fixedly connected with the ball screw.

[0012] As a preferred technical scheme, the worm gear reducer is fixedly connected with a variable-pitch guide sleeve, the variable-pitch guide sleeve is fixedly connected with a travel switch fixing support, the travel switch fixing support is fixedly connected with a travel switch adjusting support, a limit sensor is fixedly connected to the travel switch adjusting support, a guide key is fixedly connected to the screw rod, and the guide key is in sliding fit with the variable-pitch guide sleeve.

[0013] As a preferred technical scheme, the hub is rotationally connected with a plurality of blade flange shafts fixedly corresponding to the blades, the crank connecting rod comprises a variable-pitch connecting rod and a variable-pitch crank, one end of the variable-pitch connecting rod is movably connected to the synchronous disc, the other end of the variable-pitch connecting rod is movably connected to the variable-pitch crank, and the variable-pitch crank is fixedly connected to the blade flange shaft.

[0014] As a preferred technical scheme, the rod body of the variable-pitch connecting rod is a double-thread rod with positive and reverse threads, and a joint bearing is arranged at each end of the rod body, one end of the variable-pitch connecting rod is hingedly connected to the synchronous disc through the joint bearing, and the other end of the variable-pitch connecting rod is hingedly connected to one end of the variable-pitch crank through the joint bearing.

[0015] As a preferred technical scheme, a square connecting section is arranged on the blade flange shaft, the other end of the variable-pitch crank is provided with a square notch matched with the square connecting section, and the blade flange shaft is fixedly sleeved with the square notch and connected and fastened through a locking nut.

[0016] As a preferred technical scheme, the hub is fixedly connected with a guide fixing disc through a guide shaft, and one end of the wheel roller away from the generator is fixedly connected with a fairing, and the guide shaft and the guide fixing disc are located in the fairing.

[0017] The application further provides a control method of the variable-pitch mechanism of the small wind turbine generator set, adopts the variable-pitch mechanism of the small wind turbine generator set, and the driving motor is further transmissionally connected with the gear input shaft through the speed reducer, the moving time of the ball screw is calculated according to the position signal measured by the limit sensor and the pitch angle of the blade, the output speed is calculated according to the speed of the driving motor and the speed reduction ratio of the speed reducer and the variable-pitch reduction box, the variable-pitch stroke is obtained according to the moving distance of one rotation of the screw rod, and the stroke calculation formula is as follows:

[0018]

[0019] Wherein, l is the variable-pitch stroke distance, r 初 is the output speed of the variable-pitch motor, i1 and i2 are respectively the transmission ratios of the speed reducer and the variable-pitch reduction box, a is the lead of the ball screw, and t is the variable-pitch time.

[0020] The application further provides a wind turbine generator set comprising the variable-pitch mechanism of the small wind turbine generator set.

[0021] The application has the following beneficial effects:

[0022] (1) In the application, the output end of the variable pitch reduction box device or worm gear reducer is connected with the ball screw driving the rotation of the blade, and is connected with the blade through the crank connecting rod, which plays a role of reducing speed and converting the last speed reduction movement into the linear movement of the screw rod, directly pulling the synchronous disc to adjust the variable pitch, the structure is simple, and the variable pitch reduction box device or worm gear reducer can also realize large reduction ratio transmission.

[0023] (2) In the application, the flange connecting shaft and the variable pitch crank are connected in the slot opening sleeve connection mode, which effectively avoids the problems of the current fan assembly affecting the variable pitch angle, the bolt connection variable pitch rocker and the blade flange shaft leading to loosening.

[0024] (3) In the application, the variable pitch reduction box is composed of a box body, a box body front cover and a box body lower cover, which is convenient for installation, removal and maintenance of the internal structural parts of the variable pitch reduction box. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The variable pitch reduction device structure schematic diagram provided for the embodiment 1 of the application;

[0026] Figure 2 The variable pitch reduction device and generator structure schematic diagram provided for the embodiment 1 of the application;

[0027] Figure 3 The hub and generator structure schematic diagram provided for the embodiment 1 of the application;

[0028] Figure 4 The variable pitch reduction box structure schematic diagram provided for the embodiment 1 of the application;

[0029] Figure 5 The worm gear reducer structure schematic diagram provided for the embodiment 2 of the application;

[0030] Figure 6 The variable pitch device structure schematic diagram provided for the embodiment 1 of the application;

[0031] Figure 7 The variable pitch reduction device cross section structure schematic diagram provided for the embodiment 1 of the application;

[0032] Figure 8 The small wind turbine generator set variable pitch mechanism cross section structure schematic diagram provided for the embodiment 1 of the application;

[0033] Fig. 1 is a variable pitch motor; 2 is a speed reducer; 3 is a backing plate; 4 is a variable pitch speed reduction box; 5 is a speed reduction box front cover; 6 is a speed reduction box bottom cover; 7 is a ball screw; 8 is a guide key; 9 is a limit sensor; 10 is a guide support; 11 is a gear input shaft; 12 is a gear; 13 is an output shaft; 14 is a steel sleeve one; 15 is a steel sleeve two; 16 is a screw nut; 17 is a variable pitch speed reduction box device; 18 is a generator; 19 is a variable pitch device; 20 is a hub; 21 is a fairing; 22 is a blade flange shaft; 23 is a guide fixed disc; 24 is a blade bearing cover; 25 is a guide shaft; 26 is a variable pitch connecting rod; 27 is a variable pitch crank; 28 is a synchronization disc; 29 is a decoupling bearing cover; 30 is a screw assembly nut; 31 is a synchronization disc steel sleeve; 32 is a decoupling bearing steel sleeve; 33 is a blade shaft steel sleeve; 34 is a worm gear reducer support; 35 is a worm gear reducer; 36 is a variable pitch guide sleeve; 37 is a travel switch fixed support; 38 is a travel switch adjusting support. DETAILED DESCRIPTION

[0034] To make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0035] Embodiment 1

[0036] Reference Figure 1 , Figure 2 , Figure 6 The variable pitch mechanism of the small wind turbine generator set comprises a variable pitch speed reduction box device 17, a generator 18, a variable pitch device 19, a hub 20, a fairing 21 and a blade flange shaft 22. The hub 20 is rotationally connected to one end of the generator 18. The motor shaft of the generator 18 is fixedly connected to the hub 20. The hub 20 is provided with a plurality of blade flange shafts 22 rotationally matched with the hub 20. The hub 20 is fixedly connected with the fairing 21 at an end away from the generator 18. The generator 18 is fixedly connected with the variable pitch speed reduction box device 17 at an end away from the hub 20. The plurality of blade flange shafts 22 are uniformly distributed along the circumferential direction of the hub 20. The blade flange shafts 22 are connected with blades. The blades rotate under the action of wind, thereby driving the blade flange shafts 22 and the hub 20 to rotate around the axis of the hub 20, and driving the motor shaft of the generator 18 to rotate, thereby realizing wind power generation.

[0037] The hub 20 and the fairing 21 are provided with a variable pitch device 19 for driving the three blade flange shafts 22 to rotate synchronously to adjust the pitch angle according to the current wind speed, and the variable pitch reduction box device 17 reduces the rotating speed and provides driving force for the variable pitch device 19.

[0038] Referring to Figure 1 The variable pitch reduction box device 17 comprises a variable pitch reduction box 4, a driving unit, a transmission unit, a reduction box front cover 5 and a reduction box bottom cover 6. The output end of the driving unit is in transmission connection with the transmission unit and in transmission connection with the variable pitch device 19 through the transmission unit. The driving unit comprises a variable pitch motor 1, a speed reducer 2 and a square gasket plate 3. The transmission unit comprises a ball screw 7, a screw nut 16, an output shaft 13 and a gear input shaft 11.

[0039] Referring to Figure 4 、 Figure 7 The screw nut 16 and the output shaft 13 are in rotary connection in the box body of the variable pitch reduction box 4 and are fixedly connected by bolts. The ball screw 7 is screwed at the center of the screw nut 16 and the output shaft 13. The gear input shaft 11 is also in rotary connection in the variable pitch reduction box 4. The screw nut 16 and the output shaft 13 are fixedly connected at one end outside the variable pitch reduction box 4 and have a gear 12 in mesh with the gear input shaft 11. The gear input shaft 11 can drive the gear 12 and the screw nut 16 and the output shaft 13 to rotate synchronously.

[0040] One end of the variable pitch reduction box 4 is fixedly connected with the square gasket plate 3, the speed reducer 2 and the variable pitch motor 1 in sequence. The square gasket plate 3 is fixedly connected with one end of the variable pitch reduction box 4. The speed reducer 2 is fixedly connected with one end of the square gasket plate 3 away from the variable pitch reduction box 4. The variable pitch motor 1 is fixedly connected with one end of the speed reducer 2 away from the square gasket plate 3. The output end of the variable pitch motor 1 is in transmission connection with the gear input shaft 11 through the speed reducer 2 and can drive the gear input shaft 11 to rotate with its axis as the rotation shaft. The gear input shaft 11 is in mesh with the gear 12, thereby driving the gear 12 to rotate with its axis as the rotation shaft. Since the screw nut 16 is in rotary connection with the variable pitch reduction box 4, the screw nut 16 drives the ball screw 7 to move linearly along its axis when the screw nut 16 rotates.

[0041] In order to ensure the stability of the linear motion of the ball screw 7, a guide key 8 is fixedly connected with the ball screw 7, and a guide support 10 is fixedly connected with the variable pitch reduction box 4. A groove is formed in the guide support 10 and is adapted to the guide key 8. The guide key 8 partially extends into the groove, thereby limiting the rotation of the ball screw 7 and enabling the ball screw 7 to move linearly only.

[0042] The variable pitch reduction box 4 comprises a box body which is detachably fixed with the reduction box front cover 5 and the reduction box bottom cover 6 through bolts, facilitating the installation of structural members in the variable pitch reduction box 4 and the disassembly and maintenance. The variable pitch reduction box 4 adopts an aluminum alloy split box body, capable of realizing lightweight. The guide support 10 is also fixedly connected with the variable pitch reduction box 4 through bolts. The guide support 10 is also fixedly connected with a limit sensor 9. The limit sensor 9 is located at the critical point of the stroke of the ball screw 7. When the limit sensor 9 detects that the ball screw 7 moves to the area within the detection end of the limit sensor 9, the limit sensor 9 is electrically connected or in communication connection with a controller. The controller is electrically connected or in communication connection with a variable pitch reduction box device 17, a generator 18 and a variable pitch device 19. The limit sensor 9 sends a signal to the controller. The controller controls the driving unit to stop moving, so as to ensure that the blade will not be excessively opened or closed.

[0043] Referring to Figure 8 The ball screw nut 16 and the output shaft 13 are respectively rotatably connected with the variable pitch reduction box 4 through bearings. The steel sleeve one 14 and the steel sleeve two 15 are fixedly connected in the variable pitch reduction box 4. The steel sleeve one 14 is used for limiting the bearing matched with the output shaft 13 and the variable pitch reduction box 4. The steel sleeve two 15 is used for limiting the bearing matched with the ball screw nut 16 and the variable pitch reduction box 4.

[0044] The variable pitch device 19 comprises a guide fixed disc 23, a blade bearing cover 24, a guide shaft 25, a variable pitch connecting rod 26, a variable pitch crank 27, a synchronization disc 28, a decoupling bearing cover 29, a ball screw assembly nut 30, a synchronization disc steel sleeve 31, a decoupling bearing steel sleeve 32 and a blade shaft steel sleeve 33.

[0045] The ball screw 7 extends through the motor shaft of the generator 18 to the hub 20 and the nacelle 21. The ball screw assembly nut 30 is screw-connected to one end of the ball screw 7 located in the nacelle 21. The synchronization disc 28 is rotatably connected with the ball screw assembly nut 30 through two bearings. The two bearings are connected through the bearing to realize decoupling, so as to ensure that the rotation of the hub 20 will not affect the straight movement of the ball screw 7. The synchronization disc steel sleeve 31 is arranged between the two bearings and is fixedly connected with the synchronization disc 28.

[0046] Referring to Figure 6The variable pitch linkage 26 is in transmission connection with the blade flange shaft 22 on the synchronous disc 28 through the variable pitch crank 27, the rod body of the variable pitch linkage 26 adopts a double-thread rod, and fish-eye joint bearings are arranged at both ends of the rod body, one end of the variable pitch linkage 26 is hinged with the synchronous disc 28 through the joint bearing, a connecting shaft matched with the joint bearing is arranged on the synchronous disc 28, the other end of the variable pitch linkage 26 is hinged with one end of the variable pitch crank 27 through the joint bearing, and the other end of the variable pitch crank 27 is fixedly connected with the blade flange shaft 22, in the embodiment, the connection mode of the other end of the variable pitch crank 27 with the blade flange shaft 22 adopts a notched sleeve connection, a square connecting section is arranged on the blade flange shaft 22, and a square notch matched with the square connecting section is arranged at the other end of the variable pitch crank 27, after the blade flange shaft 22 is fixed with the square notch, a locking nut is fixed with the blade flange shaft 22 to limit the variable pitch crank 27.

[0047] When the ball screw 7 moves linearly, the ball screw 7 drives the screw assembly nut 30 to move left, so as to rotate synchronously through the variable pitch linkage 26, the variable pitch crank 27 and the blade flange shaft 22.

[0048] The end of the synchronous disc 28 is fixedly connected with a decoupling bearing cover 29, and the periphery of the hub 20 is also fixedly connected with a blade bearing cover 24, the blade flange shaft 22 is rotatably connected with the hub 20 through two rotating bearings, and a blade shaft steel sleeve 33 is arranged between the two rotating bearings, and the blade shaft steel sleeve 33 is used to fill the gap between the two rotating bearings.

[0049] In order to prevent the synchronous disc 28 from moving a distance greater than the set stroke, the hub 20 is also fixedly connected with a guide fixed disc 23 through a guide shaft 25, the guide fixed disc 23 is located in the fairing 21 and is used to limit the synchronous disc 28.

[0050] It should be noted that the variable pitch device 19 adopts a bias crank slider mechanism, the minimum transmission angle is 40°, the transmission efficiency is ensured, the variable pitch angle of a single variable pitch stroke is 100°, the variable pitch angle is set to be-5°-95° based on the blade zero line, the angle is set to be large, and a margin is designed to accommodate assembly errors.

[0051] In order to make the variable pitch torque larger, the variable pitch crank 27 is designed in the form of a crank, the bolt fixed connection is cancelled and the notched sleeve connection mode is adopted, the length of the variable pitch crank 27 is adjusted according to the space of the hub 20, more than 5mm safety margin is left between the hub 20 and the variable pitch crank 27, the length of the variable pitch crank 27 is taken as the maximum value, the purpose is to increase the stability and reliability of the assembly of transmission parts, and the size of the transmitted torque can not be affected by the strength, specification and number of bolts.

[0052] Variable pitch method:

[0053] The moving time of the ball screw 7 is calculated by the position signal measured by the limit sensor 9 and the pitch angle, the final output speed is calculated by the output speed of the pitch motor 1 and the speed reduction ratio of the speed reducer 2 and the pitch speed reducer 4, and the pitch stroke is obtained according to the moving distance of one rotation of the screw rod, and the stroke calculation formula is:

[0054]

[0055] l is the pitch stroke distance, r 初 is the output speed of the pitch motor 1, i1 and i2 are respectively the transmission ratios of the speed reducer 2 and the pitch speed reducer 4, a is the lead of the ball screw 7, and t is the pitch time.

[0056] Embodiment 2

[0057] Referring to Figure 5 The difference between this embodiment and embodiment 1 is that the pitch speed reducer 4 is replaced by a worm and gear speed reducer 35 in this embodiment. It should be noted that the ball screw can also be an integral structure with the worm and gear speed reducer, and the worm drives the worm gear to rotate, and the worm gear is equivalent to the nut of the lifting screw rod and matches the screw rod.

[0058] The driving unit comprises a pitch motor 1, a worm and gear speed reducer support 34, a worm and gear speed reducer 35, a pitch guide sleeve 36, a stroke switch fixed support 37, and a stroke switch adjusting support 38. The worm and gear speed reducer support 34 is fixedly connected with the generator 18, the worm and gear speed reducer support 34 is fixedly connected with the worm and gear speed reducer 35, the output shaft 13 of the pitch motor 1 is in transmission connection with the input end of the worm and gear speed reducer 35, the output end of the worm and gear speed reducer 35 is fixedly connected or screw-connected with the ball screw 7, the worm and gear speed reducer 35 can drive the ball screw to screw feed or linear feed along the axis, the worm and gear speed reducer 35 is fixedly connected with the pitch guide sleeve 36, the stroke switch fixed support 37 is fixedly connected with the pitch guide sleeve 36 through a jackscrew, the stroke switch fixed support 37 is fixedly connected with the stroke switch adjusting support 38, the stroke switch adjusting support 38 is fixedly connected with the limit sensor 9, the ball screw 7 is fixedly connected with the guide key 8, the guide key 8 is in sliding fit with the pitch guide sleeve 36, and when the guide key 8 moves to the position of the limit sensor 9, the critical stroke is reached.

[0059] Embodiment 3

[0060] The difference between this embodiment and embodiment 1 or embodiment 2 is that this embodiment further provides a wind turbine generator, which comprises the pitch mechanism of the small wind turbine generator in embodiment 1 or embodiment 2.

[0061] The above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalent features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A variable pitch mechanism for a small wind turbine generator system, comprising a generator, a hub, and a blade rotatably connected to the hub, characterized in that, The end of the generator away from the hub is provided with a variable pitch reduction box device or a worm gear reducer, and the output end of the variable pitch reduction box device or the worm gear reducer is connected with a ball screw capable of driving the blade to rotate.

2. The small wind turbine variable pitch mechanism according to claim 1, characterized in that, The variable pitch reduction box device comprises a driving motor, a variable pitch reduction box, a screw nut rotatably connected in the variable pitch reduction box, a gear input shaft rotatably connected in the variable pitch reduction box, a gear fixedly connected to the screw nut and meshing with the gear input shaft, the screw nut being screwingly connected with the ball screw, one end of the ball screw being drivingly connected with the driving motor through a reducer, and the other end of the ball screw being screwingly connected with a screw assembly nut, the screw assembly nut being rotatably connected with a synchronous disc, the synchronous disc being drivingly connected with the blade through a crank link, and the end of the generator away from the hub being further provided with a limit sensor.

3. The small wind turbine variable pitch mechanism according to claim 1, wherein, The variable pitch reduction box is fixedly connected with a guide support, the ball screw is fixedly connected with a guide key, a groove matching the guide key is formed in the guide support, the guide key is partially inserted into the groove and is in sliding fit with the groove, and the limit sensor is fixed on the guide support.

4. The small wind turbine generator set variable pitch mechanism according to claim 3, wherein The end of the generator away from the hub is fixedly connected with a worm gear reducer support, the worm gear reducer support is fixedly connected with the worm gear reducer, the worm gear reducer is fixedly connected with a variable pitch motor, the output end of the variable pitch motor is drivingly connected with the input end of the worm gear reducer, and the output end of the worm gear reducer is fixedly connected with the ball screw.

5. The small wind turbine generator set variable pitch mechanism according to claim 1, wherein The worm gear reducer is fixedly connected with a variable pitch guide sleeve, the variable pitch guide sleeve is fixedly connected with a travel switch fixing support, a travel switch adjusting support is fixedly connected to the travel switch fixing support, the limit sensor is fixedly connected to the travel switch adjusting support, the screw is fixedly connected with the guide key, and the guide key is in sliding fit with the variable pitch guide sleeve.

6. The small wind turbine generator set variable pitch mechanism according to claim 5, wherein, The hub is rotatably connected with a plurality of blade flange shafts corresponding to the blades, the crank link comprises a variable pitch link and a variable pitch crank, one end of the variable pitch link is movably connected with the synchronous disc, the other end of the variable pitch link is movably connected with the variable pitch crank, and the variable pitch crank is fixedly connected with the blade flange shaft.

7. The small wind turbine generator set variable pitch mechanism according to claim 6, wherein The rod body of the variable pitch link is a double-thread rod with positive and reverse threads, and joint bearings are arranged at both ends of the rod body, one end of the variable pitch link is hingedly connected with the synchronous disc through the joint bearing, and the other end of the variable pitch link is hingedly connected with one end of the variable pitch crank through the joint bearing.

8. The small wind turbine generator set variable pitch mechanism according to claim 1, wherein, A square connecting section is arranged on the blade flange shaft, the other end of the variable pitch crank is provided with a square slot matching the square connecting section, the blade flange shaft is fixedly sleeved with the square slot and is connected and fastened through a locking nut.

9. A control method of a variable pitch mechanism of a small wind turbine generator system, characterized by, The hub is fixedly connected with a guide fixing disc through a guide shaft, and the end of the wheel roller away from the generator is fixedly connected with a fairing, the guide shaft and the guide fixing disc being located in the fairing. The variable pitch mechanism of the small wind turbine generator set is adopted, the driving motor is further drivingly connected with the gear input shaft through the reducer, the moving time of the ball screw is calculated according to the position signal measured by the limit sensor and the pitch angle of the blade, the output rotating speed is calculated according to the rotating speed of the driving motor and the reduction ratio of the reducer and the variable pitch reduction box, the variable pitch stroke is obtained according to the moving distance of one rotation of the screw, and the stroke calculation formula is: Wherein, l is the pitch stroke distance, r 初 is the output speed of the pitch motor, i1 and i2 are the transmission ratios of the speed reducer and the pitch speed reducer, a is the lead of the ball screw, and t is the pitch time.

10. A wind turbine generator system characterized by, The small wind turbine generator set variable pitch mechanism comprises the small wind turbine generator set variable pitch mechanism as claimed in any one of claims 1-8.

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