Crank swing rod variable pitch mechanism of small H-shaped vertical axis wind turbine

Abstract

The invention discloses a crank swing rod variable-pitch mechanism of a small H-shaped vertical axis wind turbine, which belongs to the technical field of wind power generation equipment and comprises a wind turbine body, a variable-pitch mechanism rack disc, a crank rod length adjusting structure, a crank swing rod variable-pitch rule realizing mechanism and a parallelogram motion transmission mechanism. Through real-time geometric similarity of a crank swing rod mechanism and a wind speed triangle, the swing angle change rule is in one-to-one correspondence with a blade incoming flow angle, and variable pitch control without theoretical errors is achieved; a rack disc of the variable-pitch mechanism is driven by a stepping motor, and the wind direction phase is dynamically calibrated; the hydraulic push rod adjusts the length of the crank in real time to adapt to the tip speed ratio and switch the variable pitch rule; the parallelogram mechanism transmits motion through an adjustable connecting rod to adapt to different fan sizes, and interchangeability is improved. The blade is simple in design, low in cost, capable of remarkably improving the aerodynamic performance of the blade, improving the wind energy utilization coefficient, reducing the starting wind speed and avoiding stall, and suitable for efficient and stable operation of the small H-shaped vertical axis wind turbine.

Description

Technical Field

[0001] The present invention relates to the field of wind power generation equipment, and in particular, to a crank rocker variable pitch mechanism for a small H-type vertical axis wind turbine. Background Art

[0002] The variable pitch mechanism of a small H-type vertical axis wind turbine is used to improve the problems of low wind energy utilization coefficient, inability to start automatically, high starting wind speed, and the blade angle of attack may be greater than the stall angle of a fixed pitch small H-type vertical axis wind turbine. By applying the variable pitch mechanism, the blades of the small H-type vertical axis wind turbine can rotate around the blade holder according to a certain control law during the operation of the wind turbine, that is, the pitch angle of the blade changes periodically with the rotation angle of the wind turbine according to the variable pitch law, so that the angle of attack of the blade can be maintained at an optimal fixed value. In this optimal angle of attack state, the aerodynamic performance of the wind turbine blade reaches the optimal state, and the combined effect of the lift and drag on the blade and the rotation of the wind turbine is the best, increasing the working torque of the wind turbine relative to the fixed pitch state, improving the wind energy utilization coefficient of the wind turbine, reducing the starting wind speed, and avoiding blade stall under certain conditions.

[0003] In the prior art, a variable pitch mechanism is used to fit the actual variable pitch law of the blade. The motion law of the mechanism can only approximately fit the actual variable pitch motion trajectory, so there is a large theoretical error, which limits the performance of the aerodynamic performance of the wind turbine blade. At the same time, after the external dimensions of the wind turbine change, it is often necessary to re-design the size parameters of the variable pitch mechanism, with poor interchangeability and a more complex design process. Summary of the Invention

[0004] The purpose of the present invention is to provide a crank rocker variable pitch mechanism for a small H-type vertical axis wind turbine, which has a simple design, low cost, can significantly improve the aerodynamic performance of the blade, increase the wind energy utilization coefficient, reduce the starting wind speed and avoid stall, and is suitable for the efficient and stable operation of a small H-type vertical axis wind turbine.

[0005] To achieve the above object, the present invention provides a crank rocker variable pitch mechanism for a small H-type vertical axis wind turbine, including:

[0006] A small H-type wind turbine body, including:

[0007] A wind turbine frame, fixed in a wind farm and fixedly connected with a hollow frame main shaft;

[0008] A blade holder, rotating around the frame main shaft, and the blade holder main shaft serves as the power output shaft of the wind turbine. A crank rocker variable pitch law implementation mechanism is arranged on the upper surface of the blade holder;

[0009] Blades, installed on the blade holder and rotating around the blade holder to achieve variable pitch;

[0010] The pitch-changing mechanism frame disk is installed at the top end of the frame main shaft and rotates around the frame main shaft. It is controlled by a stepper motor to adapt to the change of the incoming wind direction. A pitch-changing mechanism crank rod length adjustment structure is arranged on the upper surface of the pitch-changing mechanism frame disk.

[0011] Preferably, the pitch-changing mechanism crank rod length adjustment structure is installed on the pitch-changing mechanism frame disk and includes a hydraulic push rod. The hydraulic push rod and the crank are the same component. One end of the crank has a rotary center that coincides with the rotary center of the pitch-changing mechanism frame disk, and the other end has a rotary pair located at the movable end of the hydraulic push rod. The distance between the two rotary pairs is adjusted by the hydraulic push rod.

[0012] Preferably, the crank rocker pitch-changing law implementation mechanism includes:

[0013] The crank;

[0014] The crank frame rod, which is the crossbeam section of the blade frame connected to the rocker and forms an integral rigid connection structure with the blade frame. It rotates around the frame main shaft with the blade frame. The axis of rotation of the blade frame coincides with the axis of rotation of the frame disk;

[0015] The rocker and the slider. The slider rotates around the outer end rotary pair of the crank and forms a sliding pair with the rocker;

[0016] The parallelogram pitch-changing motion law transmission mechanism includes:

[0017] The frame rod, which is a part of the blade frame. The two end rotary pairs are respectively the rotary pair for the blade pitch change rotation and the installation rotary pair of the input rod;

[0018] The input rod and the output rod, which are parallel and of equal length. The input rod is movably connected to the rocker and the relative included angle can be adjusted. The output rod is a part of the blade;

[0019] The connecting rod, which is parallel and of equal length to the frame rod. One end is hinged to the input rod, and the length can be adjusted to adapt to different fan outer contour sizes.

[0020] Preferably, the number of the blades and the branch structure of the blade frame are designed according to actual needs. Each blade corresponds to a set of the crank rocker pitch-changing law implementation mechanism and the parallelogram pitch-changing motion law transmission mechanism.

[0021] Preferably, the pitch-changing mechanism frame disk adjusts the rotation angle in real time through a stepper motor, so that the swing angle change law of the crank rocker pitch-changing law implementation mechanism is consistent with the phase of the incoming wind direction.

[0022] Preferably, the hydraulic push rod adjusts the length of the crank according to the real-time calculated tip speed ratio, so that the ratio of the length of the crank-connecting rod to the length of the crank is equal to the tip speed ratio, in order to switch the pitch-changing law under different tip speed ratios.

[0023] Preferably, the relative angle between the input rod and the swing rod is set according to the optimal angle of attack of the blade, so as to adapt to different blade airfoils.

[0024] Preferably, the length and position of the output rod are determined by the distance between the axes of the two rotating pairs on the blade, and this distance is equal to the distance between the axes of the two rotating pairs of the input rod.

[0025] Preferably, the length of the connecting rod can be adjusted, so that the pitch-changing mechanism is applicable to wind turbines with different outer contour sizes, and the interchangeability is improved.

[0026] Preferably, the stroke range of the hydraulic push rod includes the position of the axis of rotation of the pitch-changing mechanism frame disk. When the outer end rotating pair of the crank coincides with the center of rotation of the frame disk, the blade is in a fixed pitch state.

[0027] Therefore, the present invention adopts the above-mentioned crank-rocker pitch-changing mechanism of a small H-type vertical axis wind turbine, and has the following technical effects:

[0028] (1) No theoretical error: The geometric similarity principle ensures that the pitch-changing law corresponds one-to-one with the incoming flow angle, overcoming the error problem of approximate fitting of traditional mechanisms;

[0029] (2) High adaptability: The stepping motor dynamically calibrates the wind direction phase, and the hydraulic push rod adapts to the tip speed ratio in real time, adapting to complex wind fields;

[0030] (3) Low-cost interchangeability: The length of the parallelogram connecting rod is adjustable, and the angle between the input rod and the swing rod can be set according to the blade airfoil. The same mechanism can be adapted to different wind turbines;

[0031] (4) Performance improvement: The blade angle of attack is optimal, significantly improving the wind energy utilization coefficient, reducing the starting wind speed, and avoiding stall.

[0032] The technical solutions of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0033] Figure 1 is a top view of the crank-rocker pitch-changing mechanism of a small H-type vertical axis wind turbine of the present invention;

[0034] Figure 2 is a structural schematic diagram of the crank-rocker pitch-changing mechanism of a small H-type vertical axis wind turbine of the present invention;

[0035] Figure 3This is the schematic diagram of the crank-rocker variable pitch mechanism of a small H-type vertical axis wind turbine according to the present invention;

[0036] Figure 4 This is the vector synthesis relationship diagram of the airfoil angle relationship and the wind speed triangle in the crank-rocker variable pitch mechanism of a small H-type vertical axis wind turbine according to the present invention;

[0037] Figure 5 This is the pitch angle change curve diagram under the condition of 0 angle of attack in the crank-rocker variable pitch mechanism of a small H-type vertical axis wind turbine according to the present invention.

[0038] Reference numerals

[0039] Ⅰ. Wind turbine body; 1. Wind turbine frame; 2. Blade frame; 3. Blade; 4. Frame main shaft; 5. Blade frame main shaft; Ⅱ. Variable pitch mechanism frame disc; Ⅲ. Variable pitch mechanism crank rod length adjustment mechanism; 6. Hydraulic push rod; Ⅳ. Crank-rocker variable pitch law implementation mechanism; 7. Crank; 8. Crank frame rod; 9. Rocker; 10. Slide block; Ⅴ. Parallelogram variable pitch motion law transmission mechanism; 11. Frame rod; 12. Connecting rod; 13. Input rod; 14. Output rod. Detailed implementation manners

[0040] The technical solutions of the present invention will be further described below with reference to the drawings and embodiments.

[0041] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "comprising" or "including" mean that the elements or objects appearing before this term cover the elements or objects listed after this term and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0042] Embodiment 1

[0043] As Figures 1 to 3 shown, a crank-rocker variable pitch mechanism of a small H-type vertical axis wind turbine includes: a small H-type wind turbine body I

[0044] The wind turbine frame 1 is fixed to the wind farm. The hollow frame main shaft 4 is vertically arranged. The blade frame 2 is sleeved on the frame main shaft 4 through a bearing and can rotate around it.

[0045] The blade 3 is installed on the blade frame 2 and is connected to the blade frame 2 through a revolute pair. It can rotate around the revolute pair to achieve pitch change. The number of blades 3 and the branch structure of the blade frame are determined according to the design requirements.

[0046] Pitch-changing mechanism frame disk II

[0047] It is installed at the top end of the frame main shaft 4 and is controlled by a stepping motor to rotate around the main shaft. The angle is adjusted in real time to match the incoming wind direction, ensuring that the phase of the pitch-changing law is consistent with the wind direction.

[0048] Pitch-changing mechanism crank rod length adjustment structure III

[0049] The main body is a hydraulic push rod 6, which is the same component as the crank 7: One end of the crank 7 coincides with the rotation center of the pitch-changing mechanism frame disk II to ensure that the crank rocker mechanism is not offset; The axis of rotation of the blade frame 2 coincides with the axis of rotation of the pitch-changing mechanism frame disk II to ensure that the entire pitch-changing mechanism is not offset; The other end revolute pair is located at the movable outer end of the hydraulic push rod 6, and the spacing is adjusted by the hydraulic push rod 6 to adapt to the change of the tip speed ratio.

[0050] Crank rocker pitch-changing law implementation mechanism IV

[0051] Crank 7: As the length is adjusted by the hydraulic push rod 6, the slider 10 can rotate around the outer end revolute pair;

[0052] Crank frame rod 8: It is the crossbeam section in the blade frame 2 that is connected to the rocker 9 and forms an integral rigid connection structure with the blade frame 2 and rotates with the blade frame 2;

[0053] Rocker 9 and slider 10: A sliding pair is formed between the slider 10 and the rocker 9. When the crank 7 rotates, the rocker 9 is driven to swing through the slider 10. The change law of the swing angle corresponds to the incoming flow angle of the wind speed triangle in real time. As Figure 4 shown, the wind speed triangle and the pitch-changing theoretical formula are: In the formula, λ is the tip speed ratio of the wind turbine,

[0054] Parallelogram pitch-changing motion law transmission mechanism V

[0055] Frame rod 11: It is a part of the blade frame 2. The frame rod 11 and the input rod 13 are connected to the crank rocker through the same revolute pair;

[0056] Input rod 13 and output rod 14: They are parallel and of equal length. The input rod 13 is movably connected to the swing rod 9 and the included angle is adjustable to correspond to the optimal angle of attack of the blade. The output rod 14 is part of the blade 3; the revolute pair formed by the frame rod 11 and the input rod 13 is coaxially arranged with the revolute pair between the swing rod 9 and the crank frame rod 8 to ensure that the movement of the crank swing rod is transmitted to the parallelogram mechanism in a 1:1 ratio. Among them, the input rod 13 and the swing rod 9 form a combined component through phase adjustment. After the relative included angle is set according to the aerodynamic parameters, it is locked. A specific airfoil condition corresponds to a determined phase relationship. This adjustable connection design takes into account both the optimization of the angle of attack matching and the requirements of component interchangeability.

[0057] Connecting rod 12: It is parallel and of equal length to the frame rod 11. One end is hinged to the input rod 13, and the length is adjustable to adapt to different fan sizes.

[0058] Working principle:

[0059] Initial calibration:

[0060] The stepping motor drives the frame disk II to rotate, so that the pitch-changing law of the crank swing rod realizes the alignment of the phase of the swing angle change law of the mechanism IV with the real-time wind direction.

[0061] The hydraulic push rod 6 adjusts the length of the crank 7 according to the measured tip speed ratio in real time, so that the ratio of the length of the crank frame rod 8 to the crank 7 is equal to the tip speed ratio, and the corresponding pitch-changing law is switched.

[0062] Pitch-changing process:

[0063] The blade holder 2 rotates around the frame main shaft 4 under the action of wind force, driving the crank frame rod 8 to rotate synchronously.

[0064] When the crank 7 is adjusted by the stepping motor through the frame disk II to maintain a constant phase relationship with the real-time wind direction, its length is fixed by the hydraulic push rod 6. The slider 10 rotates with the blade holder 2 and slides on the swing rod 9, causing the swing rod 9 to swing.

[0065] The swing of the swing rod 9 is transmitted to the parallelogram mechanism through the input rod 13. The connecting rod 12 drives the output rod 14 to rotate, and then drives the blade 3 to rotate around the blade holder 2, realizing the change of the pitch angle according to the preset law. For example, Figure 5 as shown, Figure 5 is a special case of 0 angle of attack, that is, the pitch-changing law curve at 0 optimal angle of attack, showing the periodic change law of the pitch angle with respect to the azimuth angle. Among them, the azimuth angle refers to the azimuth angle of the wind turbine blade holder 2 relative to the incoming wind.

[0066] Blade airfoil adaptation:

[0067] According to the optimal angle of attack of different blade airfoils, based on the characteristic principle that the tangent of the fan's rotation circle is perpendicular to the radius and coincides with the action line of the relative wind speed VR, the relative angle between the input rod 13 and the swing rod 9 is adjusted as follows: when the installation baseline of the blade 3 forms an angle with the rotation radius, it is necessary to control the corresponding adjustment angles of the input rod 13 and the swing rod 9 so that the combined deflection of the two satisfies the orthogonal constraint relationship that the installation angle minus the adjustment angle equals 90 degrees. In this state, the angle deviation of the real-time pitch angle dynamic adjustment amount of the blade relative to the incoming flow wind speed direction is equal to the preset optimal angle of attack value of the blade airfoil.

[0068] Fan size adaptation:

[0069] When the outer contour size of the fan changes, adjust the length of the connecting rod 12 to ensure the parallel and equal-length relationship of the parallelogram mechanism, so that the same set of pitch-changing mechanisms can be adapted to fans of different sizes, reducing repeated design.

[0070] Embodiment 2:

[0071] Response to sudden wind direction change

[0072] When the wind speed sensor detects a change in the incoming wind direction, the stepping motor immediately drives the frame disk II to rotate to the corresponding angle of the new wind direction, and recalibrates the phase of the pitch-changing mechanism, so that the swing angle change law of the mechanism Ⅳ in the pitch-changing law of the crank and swing rod is consistent with the phase of the new incoming flow direction.

[0073] Real-time adaptation of tip speed ratio

[0074] The controller real-time collects the rotational speed of the wind turbine and the incoming wind speed, calculates the tip speed ratio and feeds it back to the hydraulic push rod 6. By adjusting the length of the crank 7, it is ensured that the length ratio of the crank frame rod 8 to the crank 7 is always equal to the real-time tip speed ratio, so as to switch the pitch-changing motion law curves under different tip speed ratios and adapt to the working condition changes during the operation of the fan.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions of the present invention or make equivalent replacements, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A crank rocker variable pitch mechanism for a small H-type vertical axis wind turbine, characterized in that Comprising: A small H-type wind turbine body, comprising: A wind turbine frame, fixed in a wind farm and fixedly connected with a hollow frame main shaft; A blade frame, rotating around the frame main shaft, with the blade frame main shaft serving as the power output shaft of the wind turbine, and a crank rocker variable pitch law implementation mechanism being arranged on the upper surface of the blade frame; Blades, installed on the blade frame and rotating around the blade frame to achieve variable pitch; A variable pitch mechanism frame disk, installed at the top end of the frame main shaft, rotating around the frame main shaft, and being controlled by a stepping motor to adapt to the change of the incoming wind direction. A variable pitch mechanism crank rod length adjustment structure is arranged on the upper surface of the variable pitch mechanism frame disk.

2. The pitch-changing mechanism of the crank and rocker for a small H-type vertical axis wind turbine according to claim 1, characterized in that: The variable pitch mechanism crank rod length adjustment structure, installed on the variable pitch mechanism frame disk, includes a hydraulic push rod. The hydraulic push rod and the crank are the same component. One end rotation center of the crank coincides with the rotation center of the variable pitch mechanism frame disk, and the other end revolute pair is located at the movable end of the hydraulic push rod. The distance between the two revolute pairs is adjusted by the hydraulic push rod.

3. The pitch-changing mechanism of the crank and rocker for a small H-type vertical axis wind turbine according to claim 1, characterized in that: The crank rocker variable pitch law implementation mechanism includes: The crank; A crank frame rod, which is the crossbeam section of the blade frame connected to the rocker, forms an integral rigid connection structure with the blade frame, and rotates around the frame main shaft along with the blade frame; the axis of rotation of the blade frame coincides with the axis of rotation of the frame disk; The rocker and the slider, the slider rotates around the outer end revolute pair of the crank and forms a sliding pair with the rocker; A parallelogram variable pitch motion law transmission mechanism, including: A frame rod, which is a part of the blade frame, and the two end revolute pairs thereof are respectively the revolute pairs for the variable pitch rotation of the blade and the installation revolute pair of the input rod; An input rod and an output rod, the two are parallel and of equal length. The input rod is movably connected with the rocker and the relative angle therebetween can be adjusted. The output rod is a part of the blade; A connecting rod, parallel and of equal length to the frame rod, with one end hinged to the input rod, and the length can be adjusted to adapt to different wind turbine outer contour dimensions.

4. The pitch-changing mechanism of a crank rocker for a small H-type vertical axis wind turbine according to claim 1, characterized in that: The number of the blades and the branch structure of the blade frame are designed according to actual requirements. Each blade corresponds to a set of the crank rocker variable pitch law implementation mechanism and the parallelogram variable pitch motion law transmission mechanism.

5. The pitch-changing mechanism of a crank and rocker for a small H-type vertical axis wind turbine according to claim 1, characterized in that: The variable pitch mechanism frame disk adjusts the rotation angle in real time through a stepping motor, so that the change law of the swing angle of the crank rocker variable pitch law implementation mechanism is consistent with the phase of the incoming wind direction.

6. The pitch-changing mechanism of the crank and rocker for a small H-type vertical axis wind turbine according to claim 1, characterized in that: The hydraulic push rod adjusts the length of the crank according to the tip speed ratio measured in real time, so that the ratio of the length of the crank frame rod to the length of the crank is equal to the tip speed ratio, in order to switch the variable pitch law under different tip speed ratios.

7. The pitch-changing mechanism of the crank rocker for a small H-type vertical axis wind turbine according to claim 1, characterized in that: The relative angle between the input rod and the rocker is set according to the optimal angle of attack of the blade to adapt to different blade airfoils.

8. The pitch-changing mechanism of the crank and rocker for a small H-type vertical axis wind turbine according to claim 1, characterized in that: The length and position of the output rod are determined by the distance between the axes of the two revolute pairs on the blade, and this distance is equal to the distance between the axes of the two revolute pairs of the input rod.

9. The pitch-changing mechanism of the crank rocker for a small H-type vertical axis wind turbine according to claim 1, characterized in that: The length of the connecting rod can be adjusted, so that the variable pitch mechanism is applicable to wind turbines with different outer contour dimensions, improving the interchangeability.

10. The pitch-changing mechanism of the crank and rocker for a small H-type vertical axis wind turbine according to claim 1, characterized in that: The stroke range of the hydraulic push rod includes the position of the axis of rotation of the pitch-changing mechanism frame disk. When the outer-end revolute pair of the crank coincides with the center of rotation of the frame disk, the blade is in a fixed pitch state.

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