Wind power generation device and method based on galloping principle

Abstract

The invention belongs to the technical field of wind power generation, and relates to a wind power generation device and method based on the galloping principle. The invention discloses a wind power generation device based on a galloping principle. The device comprises a base, a rotating shaft device, an electromagnetic damping device, a mast, a pneumatic shell and a wake flow plate, the bottom of the mast is fixed to the base, and the upper portion of the mast is sleeved with the pneumatic shell. An electromagnetic damping device and a rotating shaft device are arranged in the pneumatic shell; the wake flow plate is fixed to the outer side face of the pneumatic shell. The electromagnetic damping device is arranged in the pneumatic shell, damping energy can be converted into electric energy while the damping effect is provided, and the electromagnetic damping device serves as a shock absorber and a power generator at the same time. The pneumatic shell is connected with the mast through a rotating shaft device. The galloping principle is used for power generation, the internal electromagnetic damping device integrates vibration reduction and power generation, the galloping effect is fully used for improving the power generation performance, and structural galloping damage caused by too high wind speed is effectively restrained.

Description

Technical Field

[0001] The invention belongs to the technical field of wind power generation, and relates to a wind power generation device and method based on the galloping principle. Background Art

[0002] Wind energy is a kind of usable energy provided to humans by air flow doing work, and is a renewable energy source. Wind energy is a renewable clean energy source with large reserves and wide distribution. The kinetic energy of air flow is called wind energy.

[0003] Since wind power generation does not require the use of fuel and does not produce radiation or air pollution, wind power generation has become a global trend.

[0004] Converting the kinetic energy of wind into mechanical kinetic energy, and then converting the mechanical energy into electrical kinetic energy, this is wind power generation.

[0005] The most common device for converting wind energy into electricity is the multi-bladed wind turbine. Despite clear and recognized technological improvements that continue to be made in this area, these systems still suffer from a number of drawbacks: a) Traditional multi-blade wind turbines have many parts, high losses, high costs, are difficult to install, and have high maintenance costs; b) Currently, in order to improve its power generation efficiency, the blade design tends to be larger, which means that the speed at the tip of the blade is very high, thus posing a great threat to flocks of birds; c) The increase in blade size leads to a more complex system and an increase in initial installation costs; d) Considering the large-scale wind turbine blades, they require a larger operating space.

[0006] In order to cope with the above-mentioned limitations of multi-blade wind turbines, scholars / experts have proposed a new concept of bladeless wind turbines. For example, the technical content disclosed in the Chinese patent document (application number: 201180038079.1, patent name: vortex-induced resonance wind turbine) is: vortex-induced resonance wind turbine, including: anchor or base and mast, adjusting the natural oscillation frequency of the mast to adapt it to the generation frequency of the airflow vortex or eddy current generated after the laminar stable airflow impacts the surface of the mast. Thus, by using high electromechanical coupling materials, the absorbed air elastic deformation energy is converted into electrical energy.

[0007] The above is the design principle of the new vortex-induced resonance bladeless wind turbine. It is not difficult to see that the current bladeless wind turbine is based on the basic aerodynamic principle of vortex-induced resonance to achieve wind power generation. However, we are familiar with the fact that vortex-induced resonance will have a typical "locking interval", that is, the frequency of cross-section vortex shedding will be "locked" by the natural frequency of the structure within a certain range of incoming wind speed (that is, the two remain equal), and then "resonance" will occur. At this time, the vortex excitation force and the amplitude of the structure will increase sharply, causing the structure to swing sharply in a direction perpendicular to the incoming wind direction; once the wind speed leaves this interval, the vortex shedding frequency will no longer be "locked" by the natural frequency of the structure, and there will be no large vibration phenomenon (that is, the "resonance" disappears). The "locking interval" is a characteristic of the principle itself. The above patent uses simple tuning to expand the "locking interval", but this also leads to the power generation efficiency of the vortex-induced resonance bladeless wind turbine being constrained. Summary of the invention

[0008] The purpose of the present invention is to collect wind energy by utilizing the principle of blunt body aerodynamic galloping, aiming to solve the problems brought about by traditional multi-blade wind turbines, while addressing the challenges of narrow operating wind speed range and low wind energy utilization rate of new vortex-induced resonance bladeless wind turbines.

[0009] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is to provide a wind power generation device based on the galloping principle, which includes a base, a rotating shaft device, an electromagnetic damping device, a mast, an aerodynamic shell and a wake plate; the bottom of the mast is fixed on the base, and the aerodynamic shell is sleeved on the upper part of the mast; a rotating shaft device and an electromagnetic damping device are provided inside the aerodynamic shell; the wake plate is fixed on the outer side of the aerodynamic shell; the electromagnetic damping device is composed of a plurality of subsystems, which are arranged circumferentially in the aerodynamic shell; and the aerodynamic shell is connected to the mast through the rotating shaft device.

[0010] Preferably, the rotating shaft device comprises a turntable and a bearing; the inner ring of the bearing is connected to the mast, and the outer ring is connected to the turntable; a threaded hole is provided on the outer side of the turntable; and the turntable is connected to the inner side of the pneumatic housing through the threaded hole.

[0011] Preferably, the electromagnetic damping device comprises a plurality of electromagnetic subsystems, and the electromagnetic subsystems are electromagnetic motors or permanent magnet motors; they are arranged inside the pneumatic housing, with one end fixed to the outer ring of the bearing and the other end fixed to the inner side of the pneumatic housing.

[0012] Preferably, the ratio of the radial length of the wake plate to the diameter of the aerodynamic housing is in the range of 0.5 to 1.0, which can effectively avoid the typical "locking interval" and potentially improve power generation performance.

[0013] The present invention also provides a wind power generation method based on the galloping principle. The method utilizes the device described above to drive the aerodynamic shell to gallop through the wake plate. The aerodynamic shell transmits the galloping vibration to the mast through the rotating shaft device, and then converts it into electrical energy through the electromagnetic damping device. At the same time, the electromagnetic damping device will suppress the vibration response of the structure to a certain extent.

[0014] The invention has the following beneficial effects: the invention uses the galloping principle to generate electricity, has a wide working wind speed range, high energy collection efficiency, and a wide range of applications, and can be used in areas where traditional multi-blade wind turbines are prohibited; the internal electromagnetic damping device integrates vibration reduction and power generation functions, and while converting mechanical energy into electrical energy, it also suppresses the galloping response of the structure under excessive wind speeds to ensure structural safety. Compared with traditional multi-blade wind turbines, the device structure of the invention is safe and reliable, simple in form, and easy to transport, store, and install. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the structure of a wind power generation device based on the galloping principle in an embodiment of the present invention; Figure 2 It is a structural schematic diagram of the rotating shaft device; Figure 3 This is a schematic diagram of the installation of the electromagnetic damping device; Figure 4 It is the principle schematic diagram of the electromagnetic damping device; Figure 5 Schematic diagram of the aerodynamic principle for generating galloping for a cylindrical aerodynamic shell with different wake panels; Figure 6 The wind-induced response diagram of the cylindrical aerodynamic shell with different lengths of wake panels; Figure 7 Power diagram for wind turbines with different lengths of wake blades. DETAILED DESCRIPTION

[0016] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0017] The wind power generation device based on the galloping principle provided by the present invention has a structure as follows: Figure 1 As shown in FIG. , it includes a base 1, a mast 8, a wake plate 9, an aerodynamic shell 10, an electromagnetic damping device 11, and a rotating shaft device 12.

[0018] In this embodiment, the base 1 is fixed on the ground 2, and an anchoring area 3 is provided on the base 1. The bottom of the mast 8 is connected to the anchoring area 3 of the base 1, so that the higher parts such as the aerodynamic shell of the wind turbine can oscillate freely relying on the elasticity provided by the mast.

[0019] In this embodiment, when the wind direction changes, the wind blows onto the wake board, thereby enabling the aerodynamic housing to rotate relative to the mast through the bearing inside the rotating shaft device 12, so as to ensure that the wake board is always in the leeward direction of the incoming wind. Its working principle is similar to that of a weather vane, so as to yaw the wind turbine to ensure that the wind turbine can work normally even after the wind direction changes.

[0020] In this embodiment, the pneumatic housing 10 is a cylindrical shell structure, which is mounted on the outside of the mast 8. The mast 8 is connected to the pneumatic housing through two rotating shaft devices 12. The structure of the rotating shaft device 12 is as follows: Figure 2 As shown, it includes a turntable, a bearing, an inner ring of the bearing is fixed on the mast 8, and an outer ring of the bearing is fixed to the turntable. A threaded hole is provided on the outer periphery of the turntable, and the aerodynamic housing and the shaft device are fixed together through the threaded hole and bolts. This design can effectively ensure that the aerodynamic housing and the wake board can rotate relative to the mast.

[0021] In this embodiment, the electromagnetic damping device 11 includes a plurality of electromagnetic subsystems; the electromagnetic subsystems are electromagnetic motors or permanent magnet motors, which are arranged symmetrically, such as Figure 3 As shown, one end is connected to the inside of the aerodynamic housing, and the other end is connected to the rotating shaft device 12. There are eight damping devices arranged every 45 degrees in the circumferential direction to ensure that the damping device can operate effectively in each direction after the wind turbine yaws. The electromagnetic subsystem spatial arrangement of the electromagnetic damping device 11 can also be other numbers and other angles, as long as it can achieve multi-directional wind energy capture.

[0022] In this embodiment, the electric energy generated by the electromagnetic damping device 11 is transmitted to the electronic control and adjustment mechanism 5 in the closed box 4 in the base 1 through the cable 7 arranged in the mast 8 for processing. The cable 7 can be arranged through the groove on the ground 2 and the small hole on the base 1. The power grid 6 is responsible for transmitting this electric energy to the substation, and after the conversion of the substation, it can meet the power supply needs of the public utility company or the household.

[0023] The wind power generation device based on the galloping principle provided by the present invention has a working principle as follows: The incoming wind drives the aerodynamic shell to vibrate through the wake plate, and the aerodynamic shell transmits the vibration to the mast through the rotating shaft device. The mast is connected to the electromagnetic damping device, and the mechanical energy generated by the vibration is converted into electrical energy through the electromagnetic damping device.

[0024] The electromagnetic damping device 11 has simultaneous vibration control and energy collection effects. On the one hand, it can provide a controllable damping effect on the overall structure, suppress structural vibration, and prevent the structure from being damaged due to excessive wind speed; on the other hand, it can convert damping energy into electrical energy to generate electricity. The damping effect of the electromagnetic damping device can be changed by regulating the current flowing through it, so it has the feasibility of semi-active variable damping. Since the electromagnetic subsystems in the electromagnetic damping device are evenly distributed in all directions, this can ensure that electricity can be generated in all directions after the wind turbine is yawed. Here, the performance of the electromagnetic damping device 11 composed of all subsystems is comprehensively considered. When the electromagnetic damping device is connected to an external load, its power generation power can be generally expressed as: ; (1) Where P out is the average output power of the electromagnetic damping device, that is, the power generated by the wind turbine, t1 and t2 are the start and end times of the measurement, v is the relative speed of the end of the electromagnetic damping device, K eq and R coil are the electromagnetic coupling constant of the electromagnetic damping device 11 and the internal resistance of the motor coil, R load is the load resistance.

[0025] The corresponding electromagnetic damping effect can be generally expressed as: ; (2) Where c p is the parasitic damping coefficient of the electromagnetic damping device 11. Figure 4 A schematic diagram of the theoretical model of the electromagnetic damping device is shown, in which the motor coil inductance is very small. Considering the common low-frequency vibration conditions of the wind turbine, the effect of this inductance value can usually be ignored.

[0026] In one embodiment, the overall damping effect of the electromagnetic damping device 11 is set to a constant value. The overall damping effect of the electromagnetic damping device 11 can be determined by the current flowing through the device or the load resistance, and the change of the damping effect is realized, which depends on the optimization analysis of the galloping wind turbine generator. The specific damping effect optimization control strategy should not be used as a restriction on the rights of the invention.

[0027] At a certain wind speed, the aerodynamic damping of the structure caused by aerodynamic force is negative and greater than the structural damping, doing positive work on the structure, causing the vibration amplitude of the structure to gradually increase. This is the basic principle of galloping effect.

[0028] Installing a wake plate on a column can cause the column to vibrate, thereby significantly enhancing the wind vibration response of the column. And after installing a wake plate of appropriate length, the structure can vibrate with an amplitude exceeding that of wake plates of other lengths. Studies have shown that installing a wake plate with a radial length of 0.5 to 1.0 times the diameter of the cylinder on a cylinder can achieve a larger amplitude and the best galloping effect.

[0029] like Figure 5 As shown in (a) and (b), under the action of the incoming wind, the initial leftward movement of the wake plate produces an initial displacement y to the left, forming an equivalent wind attack angle α with the oncoming airflow. The left half is separated from the shear layer A close to the wake plate 9, and the right half is separated from the shear layer B away from the wake plate 9. Therefore, since the wind speed in the left half of the wind turbine is higher than that in the right half, the surface pressure on the left part is lower than that on the right part, which generates a leftward lateral aerodynamic force F1, the direction of action is the same as the initial movement direction, thereby enhancing the movement. In the rightward movement, this process is opposite, which is the basic mechanism of galloping.

[0030] When the radial length L of the wake plate 9 increases, the pressure area to the left becomes larger, causing the aerodynamic force F1 to increase with the increase of the radial length L of the wake plate. When L reaches the optimal length range value (L_critical), the separated shear layer can reattach to the trailing edge of the wake plate, such as Figure 5 This yields the maximum F1, as shown in (b).

[0031] Further increasing L will cause the shear layer to reattach (“reattach”) at the trailing edge of the wake vane, e.g. Figure 5 (c) shows that the "reattachment" area has a greater pressure than the separation area, so a rightward lateral force is generated in the attachment area. This rightward lateral force F2 offsets part of the leftward lateral force F1 generated by the separation area, thereby weakening the galloping vibration to a certain extent - that is, when L is too large, the galloping vibration effect will be suppressed to a certain extent.

[0032] Compared with the cylinder without the wake plate, the cylinder equipped with the wake plate of appropriate length exhibits a wider operating wind speed range and a larger vibration amplitude, which significantly improves the wind energy collection efficiency. When the radial length of the wake plate is in the optimal length range (i.e., L = L_critical), within a certain reduced wind speed range, the crosswind response of the wind turbine based on the galloping principle increases monotonically with the increase of the reduced wind speed. Considering the electromagnetic damping effect, the crosswind response can be controlled and maintained at a certain threshold, which can ensure the safety of the generator structure itself, such as Figure 6 Compared with other radial length conditions of the wake plate, the galloping effect within the optimal wake plate range is more suitable for wind power generation. Figure 7 The corresponding estimated generated power is shown.

[0033] When the radial length of the wake plate is below the optimal length range (i.e., L < L_critical), the wind speed at which the wind turbine starts to operate is approximately the same as that at the optimal length. However, as the wind speed increases to a certain extent, the crosswind response amplitude gradually decreases. Therefore, its operating wind speed range is relatively limited, and the corresponding power generation is not ideal.

[0034] In the case where the radial length of the wake plate is above the optimal length range (i.e., L > L_critical), the wind speed at which the wind turbine starts to operate is higher than that at the optimal length range. Moreover, in the subsequent operating range, at the same wind speed, the crosswind response amplitude shown is also significantly lower than that when the wake plate is within the optimal length range, and the relative power generation is also poor.

Claims

1. A wind power generation device based on the galloping principle, characterized in that: The device comprises a base, a rotating shaft device, an electromagnetic damping device, a mast, a pneumatic shell and a wake plate; the bottom of the mast is fixed on the base, and the pneumatic shell is sleeved on the upper part of the mast; a rotating shaft device and an electromagnetic damping device are arranged inside the pneumatic shell; the wake plate is fixed on the outer side of the pneumatic shell; the damping device is arranged inside the pneumatic shell; and the pneumatic shell is connected to the mast through the rotating shaft device.

2. The wind power generation device based on the galloping principle according to claim 1 is characterized in that: The rotating shaft device comprises a rotating disk and a bearing; the inner ring of the bearing is connected to the mast, and the outer ring is connected to the rotating disk; a threaded hole is arranged on the side of the rotating disk; and the rotating disk is connected to the pneumatic housing through the threaded hole.

3. The wind power generation device based on the galloping principle according to claim 1 is characterized in that: One end of the electromagnetic damping device is fixed on the outer ring of the bearing, and the other end is fixed on the inner side of the pneumatic housing.

4. The wind power generation device based on the galloping principle according to claim 1, characterized in that: The electromagnetic damping device includes a plurality of electromagnetic subsystems, which are electromagnetic motors or permanent magnet motors; the electromagnetic subsystems are arranged inside the pneumatic housing, with one end fixed on the outer ring of the bearing and the other end fixed on the inner side of the pneumatic housing.

5. The wind power generation device based on the galloping principle according to claim 1 is characterized in that: The ratio of the radial length of the wake plate to the diameter of the aerodynamic shell is in the range of 0.5 to 1.

0.

6. A wind power generation method based on the galloping principle, the method utilizing the wind power generation device as described in any one of claims 1 to 5, wherein the incoming wind drives the aerodynamic shell to gallop through the wake plate, and the aerodynamic shell transmits the galloping vibration to the mast through a rotating shaft device, which is then converted into electrical energy through an electromagnetic damping device.

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