Multi-blade wind driven generator capable of changing pitch and increasing speed along with wind

Abstract

The invention relates to a small and medium-sized wind driven generator with multiple blades capable of changing paddles along with wind and having a speed increasing function. The speed increasing function is achieved through a planetary gear train, and the speed increasing ratio i is about 3-5. The variable pitch function is achieved through the wind-following variable pitch wind wheel, the special variable pitch mechanism is adopted for the variable pitch wind wheel, the existing variable pitch technology is optimized and improved, and the variable pitch mechanism is simple and novel in structure, easy to machine and manufacture, good in lubricating effect, reliable in operation and convenient to install and maintain. Due to the adoption of the technology of changing the pitch along with the wind, the pitch angles of the wind wheel blades are constantly changed, the wind wheel always operates in the optimal lift-drag ratio state, and wind energy is captured to the maximum extent. The multiple sets of blades do not affect the rotating speed of the wind wheel, the rotating torque of the wind wheel is greatly improved, and the generated power is multiplied compared with the prior art.

Description

[0001] Technical Field: This invention relates to a wind turbine, and more particularly to a small to medium-sized wind turbine with multiple blades that change pitch angle according to wind speed and have an acceleration function.

[0002] Background technology: Existing small and medium-sized wind turbines generally do not have speed-up function and wind-following pitch function, and their wind turbines mostly adopt a fixed-wing three-blade structure.

[0003] 1. Existing small and medium-sized wind turbines generally do not have speed-increasing mechanisms, which is very disadvantageous for them operating in low-wind-speed environments. This is because the generator will not provide usable power under low-wind-speed conditions; it can only generate usable power when the wind speed reaches the cut-off speed.

[0004] 2. Existing small and medium-sized wind turbines generally use fixed-wing rotors, whose blades only undergo circular motion during operation, with the blade pitch angle remaining constant. This type of rotor is unfavorable for starting at low wind speeds, and at high wind speeds, the increased drag on the back of the blades hinders the increase in rotational speed, preventing the rotor from operating under ideal conditions. To address this contradiction, existing technologies have designed several pitch control methods, such as gear-type, spring-type, electronically controlled, and sliding sleeve-type. However, these pitch control mechanisms suffer from drawbacks such as complex structure, manufacturing difficulties, poor lubrication, low reliability, and inconvenience in installation and maintenance.

[0005] 3. Large wind turbines are equipped with pitch control. When their rotor blades encounter strong winds, they only change pitch once. The pitch control method is feathering. The purpose of the pitch control is to prevent the wind turbine from running at excessive speed and damaging the generator set. This pitch control purpose is different from the pitch control purpose of this invention.

[0006] 4. Three-bladed wind turbines are widely used because they have low solidity (the ratio of blade area to the swept plane of the turbine) and high tip speed ratio (the ratio of the linear velocity at the blade tip to the wind speed). However, this structure also has drawbacks, such as poor start-up performance, inability to fully utilize low wind speed resources, and low safety performance in strong winds.

[0007] Summary of the Invention: The wind turbine provided by this invention features multi-blade operation, wind-following pitch control, speed increase, and overspeed protection. It consists of a speed-increasing generator set and a wind-following pitch rotor. Due to the limited tower height of small and medium-sized wind turbines, they can only utilize wind speeds below 10 m / s, while low-wind-speed resources account for approximately 80% of total wind energy resources. The multi-blade wind-following pitch speed-increasing wind turbine of this invention can fully utilize low-wind-speed resources, making it ideal for operation under low-wind-speed conditions and significantly improving the power generation efficiency of the wind turbine.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] 1. The speed-increasing function of this invention is achieved through a planetary gear system. A speed-increasing mechanism is set at the front end of the generator set. The speed-increasing mechanism is a single-stage planetary gear system, consisting of a ring gear, planetary gears, a planet carrier, and a sun gear. Its key feature is that the ring gear is fixed inside the generator housing, and the planetary gears, ring gear, and sun gear mesh with each other. The planet carrier H is connected to the wind turbine shaft as the input end, and the sun gear is connected to the generator shaft as the output end. The speed-increasing ratio is approximately i = 3 to 5.

[0010] 2. The wind-following pitch function of this invention is realized by the wind turbine, the pitch mechanism, and the blades. While the pitch turbine performs circular motion, the blades continuously change the pitch angle within the range of 0° to 45°, ensuring that the turbine blades always operate at the optimal lift-to-drag ratio. There are three technical solutions for wind-following pitch turbines.

[0011] (1) The wind-following variable pitch wind turbine [one] technical solution described above consists of a hub, a rim, spokes, a pitch mechanism, and blades. Its features include: a web connecting the rim and the hub; the width of the spokes is approximately the same as the width of the hub and rim; the spokes are tilted at 45° during welding, with the tilt direction being the same as the wind turbine's rotation direction; the spokes not only provide structural support but also assist in the wind turbine's rotation. Multiple sets of support frames are arranged on the rim, with concentric holes on the support frames and the rim; a pitch mechanism is installed between two concentric holes; blades are installed on the blade stalk of each pitch mechanism; the connection point between the blade and the blade stalk must be located at the edge on one side of the blade's rotation direction, otherwise the purpose of wind-following variable pitch cannot be achieved.

[0012] (2) The technical solution of the wind-following variable pitch wind turbine [II] is characterized in that: the wind turbine is a detachable structure, the wind turbine is decomposed into several parts, and each part is connected by bolts; a screw is welded to each end of the spoke, and the screw is connected to the wheel rim and the wheel hub respectively. The wheel rim and the web are both detachable structures. The pitch mechanism and the connection method between the blade shank and the blade are the same as in technical solution [I].

[0013] (3) The wind-following variable pitch wind turbine [three] technical solution consists of a central turntable, spokes, a pitch mechanism, and blades. Its features include: the spokes are tubular; the central turntable is a flat disc on which multiple sets of spokes can be installed; one end of each spoke is fixed to the central turntable, and the other end houses the pitch mechanism; the blade stalk of the pitch mechanism is connected to the blade. The connection method between the pitch mechanism and the blade stalk is the same as in technical solution [one].

[0014] The pitch mechanism comprises a bushing, blade shank, pressure cap, limiting bolts, connecting bolts, and bearings. Its key features are: the bushing has a threaded hole, and the portion of the blade shank inserted into the bushing has an arc-shaped limiting groove; the bushing and blade shank slide together; a bearing is installed below the blade shank to increase pitch flexibility; the limiting bolts extend into the limiting grooves of the blade shank through the threaded hole on the bushing, with each limiting bolt corresponding to one limiting groove; the blade shank can rotate 0° to 45° under the control of the limiting bolts, and the arc length of the limiting groove should satisfy the blade shank's ability to rotate 0° to 45°. The pressure cap passes through the blade shank and connects to the bushing; the limiting bolts and pressure cap can be threaded or welded to the bushing. The number of limiting grooves and limiting bolts can be increased or decreased depending on the size of the wind turbine, and the blade shank length can vary.

[0015] (5) The variable pitch blades come in two forms: one is a standard blade with a raised arc on the leeward side; the other has its outer edge curved inward along the raised line, with the width of the raised part being about 1 / 3 of the blade width, and the angle between the raised part and the blade plane being about 120°. This blade can enhance the lift of the wind turbine and maximize the conversion of wind energy into mechanical energy, thereby improving the efficiency of wind energy utilization and making it easier for the wind turbine to start at low wind speeds.

[0016] (6) The braking mechanism of the wind turbine with variable pitch, comprising a control circuit, an electromagnet, and a brake disc, is characterized in that: the back of the turbine hub or central turntable also serves as the brake disc, and the electromagnet is fixed to the generator head with a gap of approximately 1-6 mm between it and the brake disc. The control circuit controls the electromagnet according to the strength of the current and voltage. When the current and voltage exceed the rated value, the electromagnet is energized and attracts the brake disc to apply braking; when the current and voltage are lower than the rated value, the electromagnet is de-energized and releases the brake disc, thus ending the braking process. Therefore, even when the wind speed reaches the whirlwind speed, there is no need to worry about damage to the generator or shutdown.

[0017] For the beneficial effects of this invention, please refer to the wind tunnel test data:

[0018] (1) Experimental wind tunnel (2m x 4m wind tunnel), the experimental prototype consisted of two identical 300W wind turbines. The comparative test data are as follows:

[0019] (2) Start the fan speed:

[0020] This technology achieves speeds of 2 m / s; existing technology achieves speeds of 4 m / s.

[0021] (3) Wind turbine speed and power at a wind speed of 6 m / s:

[0022] This technology features a wind turbine rotation speed of 374 r / min and an output power of 44.11 W.

[0023] The existing technology has a rotor speed of 214 r / min and an output power of 19.89 W.

[0024] (4) Wind turbine speed and power at a wind speed of 8 m / s:

[0025] This technology features a wind turbine rotation speed of 528 r / min and an output power of 67.46 W.

[0026] Current technology features a wind turbine rotation speed of 253 r / min and an output power of 25.68 W.

[0027] Experimental data show that this technology has the following advantages:

[0028] 1. Start with low wind speeds and make full use of low wind speed resources. Low wind speed resources account for 80% of total wind energy resources and are distributed over 65% of the country's area.

[0029] 2. Under the same wind speed, the fan speed, torque and output power are significantly increased.

[0030] 3. For wind turbines with the same power, the radial dimension of the impeller can be reduced by about 1 / 3, which reduces the moment of inertia of the impeller, improves safety, and saves manufacturing costs.

[0031] 4. Multiple sets of blades can be set, and the number of blades can be increased or decreased as needed to meet the usage requirements of fans with different power.

[0032] 5. Equipped with a braking system to prevent the wind turbine from overspeeding and damaging the generator set.

[0033] 6. In summary, this technology has a compact structure, simple process, and variable pitch with the wind, and has good safety, reliability, and extended service life. Attached image description:

[0034] Figure 1 This is a schematic diagram of a wind turbine generator and a speed-increasing mechanism.

[0035] Figure 2 This is a structural diagram of wind turbine [1].

[0036] Figure 3 This is a schematic diagram of the pitch mechanism and support installation.

[0037] Figure 4 This is a schematic diagram of the hub of wind turbine [1].

[0038] Figure 5 This is a schematic diagram of the blade structure.

[0039] Figure 6 , Figure 7 This is a schematic diagram of the pitch mechanism.

[0040] Figure 8 , Figure 9 This is a schematic diagram of the petiole structure.

[0041] Figure 10This is a partial structural diagram of the detachable wind turbine [II].

[0042] Figure 11 Schematic diagram of the hub structure of the detachable wind turbine [II]

[0043] Figure 12 This is a schematic diagram of the structure of a ringless wind turbine [3].

[0044] Figure 13 This is the control circuit diagram of the braking system.

[0045] Figure label:

[0046] 100 - Speed-increasing generator set; 101 - Gear ring of planetary gear train; 102 - Planetary gear; 103 - Sun gear; 104 - Planetary carrier; 105 - Generator rotor; 106 - Generator stator; 107 - Housing; 108 - Tail fin.

[0047] 200-Wind rotor [one]; 201-Blade; 202-Rim; 203-Bracket; 204-Body plate; 205-Hub; 206-Brake disc; 207-Electromagnet

[0048] 300-Pitch mechanism; 301-Shaft sleeve, 302-Blade shank, 303-Pressure cap, 304-Sealing ring, 305-Bearing pad, 306-Bearing, 307-Limit bolt, 308-Limit groove, 309-Base plate, 310-Connecting bolt;

[0049] 400-Wind wheel [II]; 401-Rim, 402-Web plate, 403-Nut, 404-Firming plate, 405-Hub, 406-Center hole, 407-Threaded rod, 408-Threaded hole, 409-Connecting bolt;

[0050] 500 - Windmill [III]; 501 - Central Rotary Disc; 502 - Blade Petiole.

[0051] 600 - Comparator, 601 - Pull-up voltage, 602 - Comparator output, 603 - DC power supply 1, 604 - Load voltage, 605 - Resistor 1, 606 - Resistor 2, 607 - Resistor 3, 608 - Resistor 4, 609 - Resistor 5, 610 - Resistor 6, 611 - Resistor 7. Detailed implementation method:

[0052] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments made by those skilled in the art without creative effort are within the scope of the present invention. In the description of the present invention, it should be noted that: a wind turbine refers to a device composed of a rim, blades, blade holder, spokes, hub, and central turntable that converts wind energy into rotational mechanical energy.

[0053] In the description of this invention, unless otherwise expressly specified or limited, the terms "installation," "installation," and "connection" should be broadly understood as fixed or hinged connections, which can be mechanical or welded; they can be direct connections, indirect connections via a medium, or internal connections between two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0054] Figure 1 As shown in the wind turbine structure diagram, both the speed-increasing mechanism and the generator set are installed within the casing 100. The speed-increasing mechanism is a single-stage planetary gear system. The wind turbine 200 transmits torque to the planetary carrier 104, which has 2-4 sets of planetary gears 102. The ring gear 101 is fixed inside the generator housing. The planetary gears 102 mesh with the sun gear 103 and the ring gear 101. The sun gear 103 outputs torque to drive the generator rotor 105 to rotate at a faster speed. The speed-increasing ratio of the planetary gear system is between i = 1 and 5.

[0055] Figure 2 As shown: Wind turbine 200 is the windward side, and its rotation direction is clockwise. Wind turbine 200 includes blades 201, a rim 202, a web 204, a hub 205, a support frame 203, and a pitch mechanism 300; the cross-section of blade 201 is a concave arc surface, and the leeward side of blade 201 is an outward convex arc surface. The rim 202 is a metal plate with the same width as the web 204. The web 204 is inclined at 45° when welded to the rim 202 and the hub 205.

[0056] Figure 3 As shown: Several support frames 203 are arranged on the wheel rim 202. The support frames 203 are distributed around the wheel rim 202 and welded together. Both the wheel rim 202 and the support frames 203 have concentric circular holes. The pitch mechanism 300 is inserted into these two concentric holes and welded together with them.

[0057] Figure 4 As shown: Cross-sectional view of wheel rim 202, brake disc 602 is located on the back of wheel hub 205.

[0058] Figure 5 As shown: the raised line of the outer edge of blade 201 is located at about 1 / 3 of the width of blade 201, and the angle between the raised part and the blade plane is about 120°.

[0059] Figure 6The diagram shows the structure of the pitch mechanism. The blade shank 302 is inserted into the bushing 301, with a sliding fit between the bushing 301 and the blade shank 302. A limiting groove 308 is formed in the part of the blade shank 302 inserted into the bushing 301. The arc length of the limiting groove 308 should allow the blade shank 302 to rotate from 0° to 45°. The depth of the limiting groove 308 is approximately 1 / 3 of the radius of the blade shank 302. A threaded hole is formed in the bushing 301 corresponding to the position of the limiting groove 308. A limiting bolt 307 extends into the limiting groove 308 of the blade shank 302 through the corresponding threaded hole on the bushing 301, and is fixedly connected to the bushing 301. A gap should be left between the limiting bolt 307 and the groove 308 on the blade shank 302 to ensure that the blade shank 302 can rotate freely from 0° to 45° under the control of the limiting bolt 307. A sealing ring 304 is provided on the pressure cap 303. The pressure cap 303 is connected to the bushing 301 by threads. A bearing 306 is provided at the lower end of the blade shank 302. The bottom of the blade shank 302 is a gasket 305 and a base plate 309.

[0060] Figure 7 As shown in the cross-sectional view of the pitch mechanism, the blade shank 302 and the bushing 301 are in sliding fit, and the blade shank 302 and the limiting bolt 307 are also in sliding fit, both of which ensure that the blade shank 302 rotates from 0° to 45°.

[0061] Figure 8 , Figure 9 As shown: Upper limit groove 308 of petiole 203 and blade configuration.

[0062] Figure 10 As shown: Detachable wind turbine [II] 400, the two sets of wheel rims 401 are connected by bolts 409, the joint point of the two sets of wheel rims 401 has a reinforcing rib plate 404, and a screw 407 is welded to each end of the spoke plate 402. One end of the screw 407 is inserted into the screw hole 408 of the central turntable 405, and the other end is inserted into the screw hole of the wheel rim 401 and connected with a nut.

[0063] Figure 11 As shown: Cross-sectional view of hub 405 of wind turbine [II]. There are screw holes 408 around the raised ring of hub 405, and the center of hub 405 is shaft hole 406.

[0064] Figure 12 As shown: The rimless wind turbine [III] has tubular spokes 502. One end of the spokes 502 is directly mounted on the central turntable 501, and the other end is equipped with a pitch mechanism 300. For the rimless wind turbine [III], only the pitch mechanism 300 needs to be installed inside the spokes 502. The blade shank 302 is connected to the blade 201 with bolts 310. The connection point between the blade 201 and the blade shank 302 must be located at the edge on one side of the rotation direction of the blade 201.

[0065] Figure 13The control circuit diagram 600 for the braking mechanism shows that when the current exceeds the set value (e.g., 50A), the electromagnet control voltage drops from X (3.3V) volts to 0 volts, thereby activating the electromagnet and causing the fan speed to decrease. The current drops to the set value (e.g., 25A), at which point the electromagnet control voltage returns to 3.3V, the electromagnet is deactivated, and the fan resumes normal operation. In the circuit diagram, 603 represents the DC power supply Vs, 604 represents the load voltage V_LOAD, 611 represents the comparator TLV, 612 represents the pull-up voltage VPU, 613 represents the comparator output COMP OUT, and resistors R1-605, R2-606, R3-607, R4-608, R5-609, and R6-610 are used. The electromagnet 601 of the braking mechanism is located at... Figure 1 At the front end of the generator set's casing, the brake disc 602 is located on the back of the hub 205 of the wind turbine 200, with a gap of about 6mm between them.

[0066] The innovation of this invention lies in incorporating a speed-increasing mechanism within the generator body and multiple sets of pitch blades on the wind turbine rim. This novel pitch mechanism allows the blades to adjust their pitch angle according to the wind, ensuring the wind turbine always operates at its optimal lift-to-drag ratio. Whether this invention is applied to a wind turbine or a wind pump, and regardless of any changes made to the hub or the use of metallic or non-metallic materials, all applications will fall within the scope of protection of this invention.

Claims

1. A multi-blade variable-pitch speed-increasing wind turbine, characterized in that, The application relates to a speed-increasing generator set, a wind-following variable-pitch wind wheel, a variable-pitch mechanism, a special-shaped blade and a brake control system. The speed-increasing generator set comprises a planetary gear train and a generator set, and the speed-increasing mechanism is a one-stage planetary gear train; the planetary gear train is arranged in a generator shell; a gear ring (101) is fixed; a planetary gear (102) and a sun gear (103) are in mesh with the gear ring (101); a planetary carrier (104) is connected with a wind wheel at an input end; the sun gear (103) is connected with a generator rotor (105) at an output end to transmit torque; and the speed-increasing ratio of the planetary gear train is between i=1-5. The wind-following variable-pitch wind wheel comprises a hub, a web, a variable-pitch mechanism and blades, wherein the web (204) is welded with the hub (205) and a rim (202) at an angle of 45 degrees; supports (203) are distributed on the rim (202); the variable-pitch mechanism (300) is arranged in a concentric hole of the rim (202) and the support (203); the blades (201) and blade stems (302) are connected by bolts (310); and the connecting point must be located at the edge of the blade (201) on the side of the rotating direction. The brake mechanism of the wind-following variable-pitch wind wheel comprises a control circuit, an electromagnetic iron and a brake disc, wherein the back surface of the hub (205) and a central rotating disc (501) is used as the brake disc (206); the electromagnetic iron (207) is fixed at the front end of the generator set shell and is spaced apart from the brake disc (206) by 1-6 mm; the control circuit comprises a comparator (600), an upper pull voltage (601), a comparator output (602), a direct-current power supply 1 (603), a load voltage (604), resistors 1-7 (605-611); and the electromagnetic iron (207) is controlled according to the intensity of the current and voltage; when the current and voltage exceed the rated value, the electromagnetic iron (207) is powered to brake the brake disc; and when the current and voltage are lower than the rated value, the electromagnetic iron (207) is powered off to release the brake disc (206).

2. The variable pitch mechanism of the multi-blade variable-pitch speed-increasing wind driven generator according to claim 1, comprising: The sleeve, the blade handle, the pressing cap, the limiting bolt, the connecting bolt and the bearing are composed; the blade handle (302) is in sliding fit with the sleeve (301), the blade handle (302) is inserted into the part of the sleeve (301) and is provided with a limiting recess (308), the arc length of the limiting recess (308) meets the blade handle (302) rotation of 0-45 degrees, the depth of the limiting recess (308) is about 1 / 4 of the radius of the blade handle (302), the sleeve (301) is provided with a screw hole at the position corresponding to the limiting recess (308), the limiting bolt (307) is inserted into the limiting recess (308) of the blade handle (302) through the screw hole of the sleeve (301), the limiting bolt (307) is fixedly connected with the sleeve (301), the limiting bolt (307) and the limiting recess (308) should be left with a gap, the blade handle (302) is ensured to freely rotate 0-45 degrees, the pressing cap (303) is provided with a sealing ring (304), the pressing cap (303) is connected with the sleeve (301) through threads, the lower end of the blade handle (302) is provided with a bearing (306), and the bottom of the blade handle (302) is provided with a gasket (305) and a bottom plate (309).

3. The wind wheel of the multi-blade variable-pitch speed-increasing wind turbine according to claim 1 is a split structure, which is composed of a rim (401), a hub (405) and a web (402), characterized in that: The rim (405) is divided into several parts, every two groups of rims (405) are connected by bolts (409), the connecting position of the rim (401) is provided with a reinforcing rib plate (404), the spoke plate (402) is welded with a screw rod (407) at each end, the screw rod (407) is inserted into the screw hole (408) in the rim (401) and the hub (405) and is connected by bolts, and the rim (401) and the web plate (407) are detachable structures.

4. The wind wheel of the multi-blade variable-pitch speed-increasing wind turbine according to claim 1 adopts a rimless structure, comprising blades, spokes, a central rotating disc, a pitch changing mechanism, characterized in that: The spoke rod (502) is tubular, the center rotating disc (501) is a planar disc, one end of the spoke rod (502) is connected with the center rotating disc (501), and the other end is provided with a variable pitch mechanism (300).

5. The multi-vane variable-pitch speed-increasing windmill with special-shaped blades according to claim 1, characterized in that: The outer edge of the blade (201) is inwardly bent along the bent line (208), the width of the bent part is about 1 / 3 of the width of the blade, and the angle between the bent part and the plane of the blade (201) is about 120 degrees.

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