A tidal current energy turbine with self - balancing moving resistance torque and its rotational speed regulation method

Abstract

The present invention discloses a tidal current turbine with self - balancing movement resistance torque and its rotational speed adjustment method, which includes a turbine body, a fixed frame for installing the turbine body, a depth adjustment device for adjusting the depth of the fixed frame, and a rotational speed adjustment device for adjusting the rotational speed of the impeller of the turbine body. The depth adjustment device includes an upper moving platform and a lower moving platform symmetrically arranged at the upper and lower ends of the fixed frame, and a depth driving device; the rotational speed adjustment device includes a resistance - adjusting motor, a resistance - adjusting lead screw, and a resistance - adjusting nut. The resistance - adjusting motor drives the resistance - adjusting nut to move on the resistance - adjusting lead screw to change the resistance connected to the turbine, thereby changing the rotational speed of the turbine. By adjusting the depth through the telescopic movement of the symmetrically arranged upper and lower moving platforms, a suitable working environment for the turbine is selected, and the operating resistance torque formed during the depth adjustment can be balanced. According to the real - time tidal current speed, the rotational speed of the turbine is adjusted online, so as to ensure the stable operation of the turbine, always work at the optimal tip - speed ratio, and maintain the highest energy conversion efficiency.

Description

Technical Field

[0001] The present invention relates to a water turbine, and more particularly to a self-balancing tidal energy water turbine with a movement resistance moment and a speed regulation method thereof. Background Art

[0002] Tidal energy is a renewable energy source that does not consume fuel, does not pollute the environment, is not affected by dry or flood seasons, and is inexhaustible. The development of tidal energy combines primary energy and secondary energy and is not affected by the price of primary energy. Among various marine energy sources, the development and utilization of tidal energy is the simplest, so its utilization has received extensive attention from all walks of life. The main application is power generation. The principle of tidal energy power generation is that seawater generates periodic reciprocating motion under the gravitational forces of the sun and the moon. Relying on the head formed between high and low tides, the water turbine is driven to rotate, thereby driving the generator to generate electricity. Using tidal energy to generate electricity is an effective, safe, reliable, highly stable, and clean power generation method that is not easily affected by external factors. It can not only make up for the shortage of daily electricity consumption and save the increasingly depleted precious resources, but also help protect the environment on which humans depend for survival. Therefore, the research on tidal energy by countries around the world has been in full swing.

[0003] During the process of hydroturbine power generation, the tip immersion depth and the tip speed ratio are two important parameters. According to the variation law of the impeller energy utilization rate with the tip immersion depth and the tip speed ratio, the installation depth of the hydroturbine can be determined and the rotation speed of the hydroturbine can be controlled to ensure that the hydroturbine always maintains the highest energy utilization rate. In the prior art, for the Chinese patent with the patent application number 201310685130.9 and the name "Settable Tidal Energy Turbine", the depth of the hydroturbine is actively adjusted, and it is difficult to achieve automatic adjustment when the water level changes. For the Chinese patent with the patent application number 202111292712.1 and the name "An Experimental Device for a Main-Passive Balanced Floating Hydroturbine and Its Active Balancing Control", the principle of a planar four-bar linkage is adopted to actively adjust the depth of the hydroturbine. However, when the hydroturbine moves up and down in the vertical plane, the distance from the axis of the hydroturbine to the geometric center of the experimental device will change, resulting in the formation of not only resistance but also a resistance moment, that is, a pitching moment, on the hydroturbine during the experiment, which is likely to cause stress concentration and is not conducive to the lifting of the hydroturbine. For the Chinese patent with the patent application number 201811281428.2 and the name "A Self-Balanced Tidal Energy Power Generation Device", and the Chinese patent with the patent application number 200810249755.X and the name "Lifting Double-Float Tidal Current Generator", a passive balance method is used to adjust the depth of the hydroturbine. By injecting and draining water into the water tank, the overall sinking and floating of the hydroturbine experimental device are realized, thereby achieving the adjustment of the depth of the hydroturbine. However, this adjustment method will change the overall water-facing surface of the experimental device, not only increasing the running resistance of the experimental device in water but also easily forming an additional resistance moment. For the Chinese patent with the patent application number 201710810447.9 and the name "A Hydrodynamic Performance Test Platform and Test Method for a Horizontal-Axis Tidal Energy Turbine", the rotation speed of the hydroturbine is adjusted by manually adjusting the resistance box, and it is difficult to perform online automatic adjustment of the hydroturbine rotation speed according to the real-time running speed of the device. Summary of the Invention

[0004] Object of the Invention: Aiming at the above disadvantages, the present invention provides a self-balanced tidal energy hydroturbine with a moving resistance moment that always maintains the best energy utilization rate.

[0005] The present invention also provides a method for adjusting the rotation speed of a self-balanced tidal energy hydroturbine with a moving resistance moment.

[0006] Technical solution: To solve the above problems, the present invention adopts a tidal current energy turbine with self-balancing movement resistance torque, which includes a water turbine body, a fixed frame for installing the water turbine body, a depth adjustment device for adjusting the depth of the fixed frame, and a speed adjustment device for adjusting the impeller speed of the water turbine body. The depth adjustment device includes an upper moving platform and a lower moving platform symmetrically arranged at the upper and lower ends of the fixed frame, and a depth driving device for adjusting the upper moving platform and the lower moving platform to approach or move away from the fixed frame. The upper moving platform provides buoyancy for the fixed frame, and the lower moving platform provides gravity for the fixed frame; the speed adjustment device includes a resistance adjustment motor, a resistance adjustment screw rod, and a resistance adjustment nut arranged on the resistance adjustment screw rod. The resistance adjustment motor drives the resistance adjustment screw rod to rotate, and the rotation of the resistance adjustment screw rod drives the resistance adjustment nut to move. The movement of the resistance adjustment nut on the resistance adjustment screw rod changes the resistance connected to the water turbine body, thereby changing the speed of the impeller of the water turbine body.

[0007] The upper moving platform is connected to a buoyancy block, and the upper moving platform realizes the extension and contraction of the upper moving platform through the depth driving device. Since the overall buoyancy and gravity of the water turbine do not change, after the upper moving platform extends, the overall external dimension height of the water turbine increases, and the depth of the central water turbine body relative to the water surface will also increase accordingly. Therefore, the depth of the water turbine can be adjusted.

[0008] Further, the depth driving device includes a scissor mechanism, a rack fixedly connected to the movable end of the scissor mechanism, and a gear meshing with the rack. Scissor mechanisms are arranged between the upper moving platform and the upper end face of the fixed frame, and between the lower moving platform and the lower end face of the fixed frame. The rotation of the gear drives the rack to move, and the movement of the rack drives the movable end of the scissor mechanism to move, thereby driving the upper moving platform and the lower moving platform to approach or move away from the fixed frame.

[0009] Further, the depth driving device includes a driving motor and a transmission shaft. The transmission shaft vertically passes through the fixed frame, and both ends of the transmission shaft are fixedly connected to two gears on the upper and lower end faces of the fixed frame. The output end of the driving motor is fixedly provided with a driving gear, and the driving gear meshes with one of the two gears on the upper and lower end faces of the fixed frame. Through the transmission shaft, one driving motor drives two scissor mechanisms to work.

[0010] Further, dovetail grooves are arranged on both the upper and lower end faces of the fixed frame. The rack slides in the dovetail groove, and one end of the rack is connected to the movable end of the scissor mechanism through a connecting rod.

[0011] Further, a flow guide cover is sleeved outside the water turbine body. The flow guide cover is fixedly connected to the fixed frame, and the water turbine body is arranged at the center of the fixed frame.

[0012] Furthermore, speed regulation cabins, electronic cabins, left power cabins, and right power cabins are respectively arranged at the four corners of the fixed frame. A speed regulation device is arranged in the speed regulation cabin, and a control system of the water turbine is arranged in the electronic cabin for adjusting the attitude and speed of the water turbine in real time. The left power cabin and the right power cabin are used for power storage and supply.

[0013] Furthermore, slide rail columns extending in the vertical direction are respectively arranged on both sides of the fixed frame, and the slide rail columns are located on both sides of the water-facing surface of the water turbine body. Pulleys are fixedly arranged on both sides of the fixed frame, and the pulleys slide along the slide rail columns.

[0014] The present invention also adopts a speed regulation method for a tidal current energy water turbine with self-balanced movement resistance torque, including the following steps:

[0015] Step 1: Detect the actual movement speed V of the tidal current 实际 ;

[0016] Step 2: According to the relationship between the energy utilization rate of the impeller and the tip speed ratio obtain the optimal tip speed ratio λ when the impeller has the highest energy utilization rate;

[0017] Step 3: Obtain the target speed n of the water turbine body according to the obtained optimal tip speed ratio 目标 ;

[0018] Step 4: According to the relationship between the speed of the water turbine body and the resistance connected to the water turbine body, control the speed regulation device to adjust the resistance adjusting nut, change the resistance connected to the water turbine body, so as to change the speed of the water turbine body and make the speed of the water turbine body reach the target speed;

[0019] Step 5: Detect the actual movement speed of the tidal current in real time, and adjust the speed of the water turbine body in real time according to the detected actual movement speed of the tidal current.

[0020] Furthermore, the specific content of Step 4 includes:

[0021] Step 41: According to the mechanical transmission characteristics of the water turbine, there is:

[0022]

[0023]

[0024] T m = C M φI

[0025]

[0026]

[0027] where, J ris the inertia of the turbine body drive system reduced to the turbine main shaft, w r is the angular velocity of the turbine main shaft rotation, T r is the hydrodynamic torque obtained by the turbine body, T m is the electromagnetic torque, T D is the damping torque, r is the radius of the turbine impeller, C M is the torque constant, φ is the magnetic flux, I is the current in the circuit, E is the induced electromotive force, R a is the resistance value of the resistance adjusting device connected, C E is the electromotive force constant, C n is the damping coefficient;

[0028] The relationship between the rotational speed of the turbine body and the resistance connected to the turbine body is obtained:

[0029]

[0030] Through the detected actual movement speed V of the tidal current 实际 and the optimal tip speed ratio λ to represent the target rotational speed n 目标 Then there is:

[0031]

[0032] Step 42: Calculate the target displacement l of the resistance adjusting nut 目标 :

[0033]

[0034] Then there is:

[0035]

[0036] Among them, l 总 is the total length of the adjusting resistance, R 总 is the total resistance value of the adjusting resistance;

[0037] Step 43: Control the resistance adjusting motor to drive the resistance adjusting lead screw to rotate to control the displacement of the resistance adjusting nut, and then monitor the displacement data of the resistance adjusting nut through the displacement sensor, and control the resistance adjusting motor according to the displacement data of the resistance adjusting nut to form a closed-loop control, and finally make the displacement of the resistance adjusting nut be l 目标 .

[0038] Beneficial effects: Compared with the prior art, the significant advantage of the present invention is that when the current working environment of the water turbine is not suitable, through the extension and contraction of the upper moving platform and the lower moving platform, the depth can be adjusted within a predetermined range, thereby changing the distance from the blade tip to the water surface, selecting a suitable working environment for the water turbine, adjusting the depth through the extension and contraction of the upper moving platform and the lower moving platform, reducing the driving energy for depth adjustment, and thus reducing energy consumption. The symmetrically arranged upper moving platform and lower moving platform can balance the operating resistance moment formed when the water turbine adjusts the water depth. And when the top buoyancy block generates a pitching moment due to the interference of waves and turbulence, the symmetrically arranged tail gravity block can generate a reverse moment to offset the pitching moment at the top, thereby realizing the self-balancing of the water turbine resistance. When the flow rate is small, the speed regulating resistor is adjusted to increase, the current in the circuit decreases, the operating resistance of the water turbine decreases, and the rotational speed increases; when the flow rate is large, the speed regulating resistor is adjusted to decrease, the current in the circuit increases, the operating resistance of the water turbine increases, and the rotational speed decreases. According to the real-time tidal current speed, the rotational speed of the water turbine is adjusted online, so as to ensure the stable operation of the water turbine, always work at the optimal tip speed ratio, and maintain the highest energy conversion efficiency. Brief Description of the Drawings

[0039] Figure 1 is a schematic diagram of the overall structure of the water turbine of the present invention;

[0040] Figure 2 is a front view of the contracted state of the water turbine of the present invention;

[0041] Figure 3 is a schematic diagram of the structure of the upper moving platform in the extended state of the present invention;

[0042] Figure 4 is a left view of the upper moving platform in the extended state of the present invention;

[0043] Figure 5 is a front view of the upper moving platform in the extended state of the present invention;

[0044] Figure 6 is Figure 5 a cross-sectional view taken along line A-A in

[0045] Figure 7 is Figure 5 a partially enlarged view of the rack chute;

[0046] Figure 8 is Figure 6 a partially enlarged view of the chute connection;

[0047] Figure 9 is Figure 6 a partially enlarged view of the rack connection;

[0048] Figure 10 is a front view of the main body structure in the middle of the present invention;

[0049] Figure 11 is the left view of the intermediate main body structure of the present invention;

[0050] Figure 12 is Figure 10 the sectional view taken along line B-B in;

[0051] Figure 13 is the schematic diagram of the overall structure of the speed regulation cabin in the present invention;

[0052] Figure 14 is the internal structure view of the speed regulation cabin in the present invention;

[0053] Figure 15 is the structure view of the fixed module of the speed regulation cabin in the present invention;

[0054] Figure 16 is the structure view of the resistance adjustment module in the present invention;

[0055] Figure 17 is the top view of the resistance adjustment module in the present invention;

[0056] Figure 18 is Figure 17 the sectional view taken along line C-C in;

[0057] Figure 19 is Figure 17 the sectional view taken along line D-D in;

[0058] Figure 20 is the schematic diagram of the structure of the lower moving platform in the present invention;

[0059] Figure 21 is the working principle diagram of adjusting the tip immersion depth of the water turbine in the present invention;

[0060] Figure 22 is the working principle diagram of adjusting the speed of the water turbine in the present invention;

[0061] Figure 23 is the force analysis diagram of the water turbine in the present invention;

[0062] Figure 24 is the schematic diagram of the structural dimension relationship of the upper moving platform in the present invention;

[0063] Figure 25 is the schematic diagram of the electrical circuit of the generator in the present invention;

[0064] Figure 26 is the control flow chart of the speed regulation device in the present invention. Detailed implementation manners

[0065] Example 1

[0066] As Figure 1 、Figure 2 As shown in the figure, in this embodiment, a tidal current turbine with self - balancing of moving resistance torque includes a left column 72, a right column 73, a pulley 74, an upper moving platform 1, a middle main body 2, and a lower moving platform 3. Among them, the middle main body 2 includes a fixed frame 4, a speed - regulating cabin 5, an electronic cabin 6, a left power cabin 9, a right power cabin 10, and a water turbine module 8. The upper moving platform 1 is fixed to the upper end face of the fixed frame 4 by bolts. Inside the fixed frame 4, there are installed a speed - regulating cabin 5, an electronic cabin 6, a left power cabin 9, a right power cabin 10, and a water turbine module 8. The lower moving platform 3 is fixed to the lower end face of the fixed frame 4 by bolts.

[0067] As Figures 3 to 5 shown, the upper moving platform 1 mainly includes buoyancy materials 11, an upper scissor mechanism, a fixed bottom plate A24, an upper rack 25, a motor 26, an upper gear 27, and an upper connecting rod 28; the upper scissor mechanism includes a left fixed frame A12, a left upper X - shaped rod A13, a left upper X - shaped rod B14, a left upper X - shaped rod C15, a left upper X - shaped rod D16, a left fixed frame B17, a right fixed frame A18, a right upper X - shaped rod A19, a right upper X - shaped rod B20, a right upper X - shaped rod C21, a right upper X - shaped rod D22, and a right fixed frame B23. On both sides of the fixed bottom plate A24, there are respectively three threaded holes, and the left fixed frame B17 and the right fixed frame B23 are fixed to the fixed bottom plate A24 by bolts. A through - hole is opened in the middle of the left upper X - shaped rod C15 and the left upper X - shaped rod D16 and they are connected by a pin shaft to form a first - level X - shaped mechanism. The left upper X - shaped rod A13 and the left upper X - shaped rod B14 also form a first - level X - shaped mechanism through a pin shaft. The two first - level mechanisms are connected by a pin shaft to jointly form a second - level X - shaped mechanism. In the second - level X - shaped mechanism, the left upper X - shaped rod C15 is fixed to the left fixed frame B17 by a pin shaft and a retaining ring, and the left upper X - shaped rod D16 is connected to the upper connecting rod 28 by a pin shaft and is installed in the chute of the left fixed frame B17; in the second - level X - shaped mechanism, the left upper X - shaped rod A13 is connected to the left fixed frame A12 by a pin shaft and a retaining ring, and the left upper X - shaped rod B14 is installed in the chute of the left fixed frame A12 through a shaft; similarly, the right upper X - shaped rod A19, the right upper X - shaped rod B20, the right upper X - shaped rod C21, and the right upper X - shaped rod D22 jointly form a second - level X - shaped mechanism by pin shafts and are also installed on the right fixed frame B23 and the right fixed frame A18. Through - holes are opened on both sides of the buoyancy materials 11, and they are installed on the left fixed frame A12 and the right fixed frame A18 by bolts and nuts.

[0068] Figures 6 to 9 As shown, the driving motor 26 on the upper moving platform 1 is installed at the bottom of the fixed bottom plate A24 by screw connection. The upper gear 27 meshes with the driving motor 26, and the upper gear 27 is fixed to the transmission shaft 32 by a retaining ring and a nut. The upper gear 27 also meshes with the upper rack 25. The lower end of the upper rack 25 is installed in the dovetail groove on the fixed bottom plate A24 and is fixed to the upper connecting rod 28 by bolts.

[0069] As Figures 10 to 12 shown, the middle body 2 includes a fixed frame 4, a speed regulation cabin 5, an electronic cabin 6, a left power cabin 9, a right power cabin 10, and a water turbine module 8. Among them, a speed regulation cabin 5, an electronic cabin 6, a left power cabin 9, and a right power cabin 10 are respectively fixed inside the four corners of the fixed frame 4, and a water turbine module 8 is installed at the center of the fixed frame 4.

[0070] The water turbine module 8 is mainly composed of a water turbine body 30, a water turbine fixing plate 31, a transmission fixed sleeve 33, a guide hood 29, a water turbine fixing rod A 34, and a water turbine fixing rod B 35. Among them, the water turbine body 30 is fixedly installed on the water turbine fixing plate 31 through bolts and nuts, and the water turbine fixing plate 31 is fixedly connected to the fixed frame 4 through the water turbine fixing rod A 34 and the water turbine fixing rod B 35 in the horizontal direction through bolts. Four symmetrical through holes are opened on the guide hood 29, and the water turbine fixing rod A 34 and the water turbine fixing rod B 35 fix the water turbine at the center of the guide hood 29 through the horizontal through holes, while the fixed sleeve 33 completely fixes the guide hood 29 through the vertical through holes. A transmission shaft 32 is installed inside the fixed sleeve 33, and an upper gear 27 and a lower gear are installed up and down on the transmission shaft 32 and are fixedly installed through shaft shoulders and nuts. The rotation of the motor 26 drives the upper gear 27 to rotate, and the transmission shaft 32 rotates with the upper gear 27 and will drive the lower gear to rotate together, thereby synchronously driving the synchronous extension and contraction of the upper moving platform 1 and the lower moving platform 3.

[0071] As Figure 13 、 Figure 14 shown, the speed regulation cabin 5 mainly includes a rear sealing end cover 36, a rear flange 37, a cabin cylinder 38, a front flange 39, a front sealing end cover 40, a rear fixed module 41 of the speed regulation cabin, a resistance adjustment module 42 (speed regulation device), and a front fixed module 43 of the speed regulation cabin. The rear sealing end cover 36 and the rear flange 37 are installed on the cabin cylinder 38 together through bolts and nuts, and an O-ring seal is installed between them; the front sealing end cover 40 and the front flange 39 are also connected to the cabin cylinder 38 and use a sealing ring to ensure the sealing performance.

[0072] As Figure 15 shown, the rear fixed module 41 of the speed regulation cabin and the front fixed module 43 of the speed regulation cabin are exactly the same, and also include a fixing plate A 44, an L-shaped connecting piece 45, a connecting shaft 46, a fixing plate B 47, a fixing plate C 48, and a fixing plate D 49. Through holes are opened around the fixing plate A 44 and the fixing plate D 49, and they are fixedly connected together through four connecting shafts 46 and nuts. The rear end of the fixing plate C 48 is installed between the fixing plate A 44 and the fixing plate D 49 through four L-shaped connecting pieces 45 and bolts and nuts; the fixing plate B 47 is installed between the fixing plate A 44 and the fixing plate D 49 in the same way.

[0073] As Figures 16 to 19As shown in the figure, the resistance adjustment module 42 mainly includes a resistance adjustment motor 50, a resistance adjustment gear 51, a limit rod A 52, a limit rod B 53, an adjustment resistor 54, a resistance adjustment lead screw 55, a resistance adjustment plate 56 and a resistance adjustment nut 57. The resistance adjustment motor 50 is installed on the resistance adjustment plate 56 by screws. There are two protruding structures on the front and rear of the resistance adjustment plate 56 for installing the resistance adjustment lead screw 55. The front and rear ends of the resistance adjustment lead screw 55 are axially positioned and fixed by shoulders and shaft end retaining rings. A resistance adjustment gear 51 is installed at the rear end of the resistance adjustment lead screw 55 and is positioned by an shaft end retaining ring, a shoulder and a flat key. A resistance adjustment nut 57 is installed on the resistance adjustment lead screw 55, and the circumferential movement of the resistance adjustment nut 57 is restricted by the limit rod A 52 and the limit rod B 53 installed on the resistance adjustment plate 56 to achieve the axial movement of the resistance adjustment nut 57.

[0074] As Figure 20 shown, the lower moving platform 3 includes a fixed bottom plate B 58 and a lower scissor mechanism. The lower scissor mechanism includes components such as a lower left X-shaped rod A 59 and has the same structure as the upper moving platform 1. First, a primary X-shaped telescopic mechanism is composed of components such as a lower left X-shaped rod A 59 and a lower left X-shaped rod B 60, and then a secondary X-shaped telescopic mechanism is formed by connecting the primary X-shaped telescopic mechanisms end to end. It is installed on the left fixed frame C 63 etc. and connected to the fixed plate 58B. The gravity block 71 is installed on the left fixed frame D and the right fixed frame D 66 by bolts and nuts.

[0075] As Figure 21 shown, the weight of the overall structure of the water turbine remains constant and it is immersed in water during operation. Therefore, the buoyancy of the water turbine in water remains constant. The forward rotation of the motor 26 drives the upper gear 27 to rotate, and finally drives the upper rack 25 that meshes with the upper gear 27. The upper rack 25 slides in the chute of the fixed bottom plate A 24, driving the upper connecting rod 28 fixedly connected to the upper rack 25. The movement of the upper connecting rod 28 drives the secondary X-shaped telescopic mechanisms on both sides to achieve the extension and contraction of the upper moving platform 1. The upper gear 27 is installed on the transmission shaft 32. The rotation of the upper gear 27 drives the transmission shaft 32 and the lower gear to rotate synchronously. By driving the secondary X-shaped telescopic mechanism, the upper moving platform 1 and the lower moving platform 3 extend and contract synchronously, changing the depth of the water turbine in water, thereby adjusting the immersion depth of the blade tip. Also, because the distances of upward and downward extension are the same and the water-facing surface is symmetrical, the force is balanced during the movement, achieving self-balancing of the resistance moment.

[0076] As Figure 21As shown in the figure, the working principle of adjusting the tip immersion depth of the water turbine body is as follows: When the current working environment of the water turbine is not suitable, change the tip immersion depth of the water turbine. The rotation of the motor 26 drives the upper gear 27 to rotate, and finally drives the movement of the upper rack meshing with the upper gear. Since the upper rack is installed in the chute of the fixed bottom plate A, the upper rack can only move along the chute and drives the upper connecting rod fixedly connected to the upper rack. Both sides of the upper connecting rod drive the expansion and contraction of the two-stage X-shaped telescopic mechanism on both sides through the coupling shaft, so that the upper moving platform expands and contracts. The upper gear is installed on the transmission shaft, and the lower gear also installed on the transmission shaft is driven by the motor to rotate synchronously, and drives the movement of the lower rack meshing with the lower gear. The lower rack is installed in the chute of the fixed bottom plate B and moves together with the lower connecting rod. The movement of the lower connecting rod drives the expansion and contraction of the two-stage X-shaped mechanism on both sides, and finally drives the synchronous expansion and contraction of the lower moving platform and the upper moving platform. The water turbine will sink and float under the action of gravity and buoyancy, thereby changing the depth of the water turbine and further changing the tip immersion depth of the water turbine body, so that the water turbine reaches a suitable working environment. The tip immersion depth h 1 and the initial tip immersion depth h 0 、the sinking displacement h 2 of the water turbine have the relationship: h 1 =h 0 +h 2 , that is, h 2 =h 1 -h 0 .

[0077] As Figure 22 shown, the tip speed ratio of the water turbine is adjusted by adjusting the water turbine speed. The working principle of adjusting the water turbine speed is as follows: The output end of the generator is connected to the rheostat device after passing through the rectifier device and the filter capacitor to form a circuit. During the operation of the generator, a current will be generated in the circuit. Adjust the resistance value of the rheostat device connected to the circuit. When the resistance value increases, the current in the circuit decreases, the armature current of the water turbine decreases, the electromagnetic torque decreases, and the water turbine speed increases; when the resistance value decreases, the current in the circuit increases, the armature current of the water turbine increases, the electromagnetic torque increases, and the water turbine speed decreases. Therefore, the water turbine speed can be adjusted by adjusting the resistance value of the rheostat device connected to the circuit.

[0078] As Figure 23 shown, the tidal current forms a thrust on the water-facing surface of the water turbine. Among them, the force on the upper moving platform is F 1 , the force on the middle main body is F 2 , the force on the lower moving platform is F 3 . The left and right columns form a thrust on the water turbine through the pulleys to resist F 1 , F 2 , F 3 . The reaction force F is received at the pulley4 and F 5 . Thus, the balance formula is obtained:

[0079]

[0080] Then,

[0081]

[0082] where l 1 is the distance from the water-facing surface of the lower moving platform to the geometric center of the middle main body, Δl is the difference in the distances from the upper and lower moving platforms to the geometric center of the middle main body, and l 2 is the distance from the upper pulley and the lower pulley to the geometric center of the middle main body.

[0083] The frictional forces between the water turbine and the left and right columns are F 摩 =(|F 4 | + |F 5 |)μ, where μ is the coefficient of friction. Then,

[0084]

[0085] In the case of Δl≠0,

[0086] When ,

[0087] When , At this time,

[0088] Since Therefore, F 摩2 > F 摩1 .

[0089] In the case of Δl = 0, F 摩3 =(2F 1 + F 2 )μ.

[0090] It can be seen that when the difference in the moving distances of the upper and lower moving platforms exceeds the threshold, the frictional force increases, the resistance to the up and down movement of the water turbine increases, and the difficulty of depth adjustment increases. When the moving distances of the upper and lower moving platforms are always equal, the frictional force remains unchanged. In the present invention patent, the moving distances of the upper and lower moving platforms are always equal, so the frictional force remains unchanged, which is beneficial to the depth adjustment of the water turbine.

[0091] As Figure 24 shown, the relationship between the intermediate variable h 3 and the sinking displacement h 2 of the water turbine is h 2 = 4h 3, intermediate variable h 3 The relationship with the number of rotations N of the driving gear is Then the number of rotations N of the driving gear and the sinking displacement h of the water turbine 2 The relationship is Since h 2 = h 1 - h 0 , so Among them, h 0 is the initial tip immersion water depth, a is the initial distance between the two rod ends of the secondary X-type mechanism, b is the length of a single rod, z is the number of teeth of the driving gear, m is the module of the driving gear, h 1 is the tip immersion water depth reached at this time.

[0092] As Figure 25 shown, the electrical circuit relationship of the generator is Among them, E is the induced electromotive force of the generator, R a is the resistance connected by the resistance adjustment device, I is the current in the circuit, R 总 is the maximum resistance of the adjustment resistance, l 总 is the total length of the adjustment resistance, l 目标 is the displacement distance of the resistance adjustment nut.

[0093] Embodiment 2

[0094] A water turbine speed regulation method in this embodiment includes the following steps:

[0095] (1) Detect the actual movement speed V of the tidal current by the speed sensor 实际 ;

[0096] (2) According to the relationship between the impeller energy utilization rate and the tip speed ratio Obtain the optimal tip speed ratio λ at the highest energy utilization rate of the impeller;

[0097] (3) According to the obtained optimal tip speed ratio, obtain the target speed n of the water turbine body 目标 , from get Among them, r is the radius of the water turbine impeller;

[0098] (4) According to the relationship between the speed of the water turbine body and the resistance connected to the water turbine body, control the speed regulation device to adjust the resistance adjustment nut, change the resistance connected to the water turbine body, so as to change the speed of the water turbine body and make the speed of the water turbine body reach the target speed; specifically including:

[0099] (41) According to the mechanical transmission characteristics of the water turbine, there is J r is the inertia of the water turbine drive system reduced to the water turbine shaft, the angular velocity of the main shaft rotation Tr is the hydrodynamic torque obtained by the water turbine, and this value is measured by a torque sensor inside the water turbine, T m is the electromagnetic torque (due to the induced electromotive force formula then the current in the circuit According to the electromagnetic torque formula T m = C M φI, we get where C E is the electromotive force constant, φ is the magnetic flux, R a is the resistance connected by the resistance adjusting device, C M is the torque constant), the damping torque T D = C n n 目标 , C n is the damping coefficient, so we have then

[0100] (42) Calculate the target displacement l of the resistance adjusting nut 目标 , since then

[0101] (43) The closed-loop control adjusts the displacement of the nut of the resistance adjusting device to l 目标 , as Figure 26 shown, the measured tidal current velocity V 实际 is transmitted to the motor driver as a control quantity through calculation. The motor driver controls the motor, the motor drives the lead screw to rotate to control the displacement of the resistance adjusting nut, and then the displacement sensor monitors the displacement data of the resistance adjusting nut and transmits it to the displacement controller of the resistance adjusting nut to form a closed-loop control, and finally the displacement of the resistance adjusting nut is l 目标 ;

[0102] (5) Return to step (1), and continuously detect the actual movement speed of the tidal current, and adjust the rotation speed of the water turbine body in real time according to the detected actual movement speed of the tidal current.

Claims

1. A method for regulating the rotational speed of a tidal current energy turbine with self - balancing movement resistance moment, characterized in that, the tidal current energy turbine includes a turbine body (30), a fixed frame (4) for installing the turbine body, a depth adjustment device for adjusting the depth of the fixed frame (4), and a rotational speed adjustment device for adjusting the rotational speed of the impeller of the turbine body. The depth adjustment device includes an upper moving platform (1) and a lower moving platform (3) symmetrically arranged at the upper and lower ends of the fixed frame, and a depth driving device for adjusting the upper moving platform and the lower moving platform to approach or move away from the fixed frame (4). The upper moving platform (1) provides buoyancy for the fixed frame (4); the lower moving platform (3) provides gravity for the fixed frame (4); the rotational speed adjustment device includes a resistance - adjusting motor (50), a resistance - adjusting lead screw (55), and a resistance - adjusting nut (57) arranged on the resistance - adjusting lead screw (55). The resistance - adjusting motor (50) drives the resistance - adjusting lead screw (55) to rotate, the rotation of the resistance - adjusting lead screw (55) drives the resistance - adjusting nut (57) to move, and the movement of the resistance - adjusting nut (57) on the resistance - adjusting lead screw changes the resistance connected to the turbine body, thereby changing the rotational speed of the impeller of the turbine body; the depth driving device includes a scissor mechanism, a rack fixedly connected to the movable end of the scissor mechanism, and a gear meshing with the rack. Scissor mechanisms are arranged between the upper moving platform and the upper end face of the fixed frame, and between the lower moving platform and the lower end face of the fixed frame. The rotation of the gear drives the rack to move, and the movement of the rack drives the movable end of the scissor mechanism to move, thereby driving the upper moving platform and the lower moving platform to approach or move away from the fixed frame (4); the method for regulating the rotational speed of the tidal current energy turbine includes the following steps: Step 1: Detect the actual movement speed V of the tidal current 实际 ; Step 2: According to the relationship between the impeller energy utilization rate and the tip speed ratio obtain the optimal tip speed ratio λ at the highest impeller energy utilization rate; where T r is the hydrodynamic torque obtained by the water turbine body, and r is the radius of the water turbine impeller; Step 3: Obtain the target speed n of the turbine body according to the obtained optimal tip speed ratio 目标 ; Step 4: According to the relationship between the rotational speed of the turbine body and the resistance connected to the turbine body, control the rotational speed adjustment device to adjust the resistance - adjusting nut, change the resistance connected to the turbine body, thereby changing the rotational speed of the turbine body to make the rotational speed of the turbine body reach the target rotational speed; Step 5: Real - time detect the actual movement speed of the tide, and adjust the rotational speed of the turbine body in real time according to the detected actual movement speed of the tide.

2. The method for regulating the rotational speed of the tidal current energy turbine according to claim 1, characterized in that, the depth driving device includes a driving motor (26) and a transmission shaft (32). The transmission shaft (32) vertically passes through the fixed frame (4), and both ends of the transmission shaft (32) are fixedly connected to two gears on the upper and lower end faces of the fixed frame respectively. The output end of the driving motor (26) is fixedly provided with a driving gear, and the driving gear meshes with one of the two gears on the upper and lower end faces of the fixed frame. Through the transmission shaft (32), one driving motor (26) drives the two scissor mechanisms to work.

3. The method for regulating the rotational speed of the tidal current energy turbine according to claim 1, characterized in that, dovetail grooves are arranged on both the upper and lower end faces of the fixed frame (4), the rack slides in the dovetail groove, and one end of the rack is connected to the movable end of the scissor mechanism through a connecting rod.

4. The method for regulating the rotational speed of the tidal current energy turbine according to claim 1, characterized in that, A guide hood (29) is sleeved outside the water turbine body (30). The guide hood (29) is fixedly connected to the fixed frame (4), and the water turbine body (30) is arranged at the center of the fixed frame (4).

5. The rotational speed regulation method of the tidal current energy water turbine according to claim 1, characterized in that, speed regulation cabins (5), electronic cabins (6), left power cabins (9), and right power cabins (10) are respectively arranged at the four corners of the fixed frame (4). A rotational speed regulation device is arranged in the speed regulation cabin (5), and a control system of the water turbine is arranged in the electronic cabin (6) for adjusting the attitude and rotational speed of the water turbine in real time; the left power cabin (9) and the right power cabin (10) are used for power storage and supply.

6. The rotational speed regulation method of the tidal current energy water turbine according to claim 1, characterized in that, slide rail columns extending in the vertical direction are respectively arranged on both sides of the fixed frame (4), and the slide rail columns are located on both sides of the water turbine body facing the water surface. Pulleys (74) are fixedly arranged on both sides of the fixed frame (4), and the pulleys slide along the slide rail columns.

7. The rotational speed regulation method according to claim 6, characterized in that, the specific content in step 4 includes: Step 41: According to the mechanical transmission characteristics of the water turbine, there is: T m = C M φI Among them, J r is the inertia of the turbine body drive system reduced to the turbine main shaft, w r is the rotational angular velocity of the turbine main shaft, T r is the hydrodynamic torque obtained by the turbine body, T m is the electromagnetic torque, T D is the damping torque, r is the radius of the turbine impeller, C M is the torque constant, φ is the magnetic flux, I is the current in the circuit, E is the induced electromotive force, R a is the resistance value of the resistance adjustment device connected, C E is the electromotive force constant, C n is the damping coefficient; Obtain the relationship between the rotational speed of the water turbine body and the resistance connected to the water turbine body: The actual moving speed V of the detected tidal current 实际 And the target rotational speed n is represented by the optimal tip speed ratio λ 目标 Then there is: Step 42: Calculate the target displacement l of the resistance adjusting nut 目标 : Then there is: Among them, l 总 is the total length of the adjustable resistor, and R 总 is the total resistance value of the adjustable resistor; Step 43: Control the rheostat motor to drive the rheostat lead screw to rotate, control the displacement of the rheostat nut, then monitor the displacement data of the rheostat nut through a displacement sensor, and control the rheostat motor according to the displacement data of the rheostat nut to form a closed-loop control, and finally make the displacement of the rheostat nut be l 目标 .

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