Small fan applied to extreme environment

Abstract

The utility model relates to a small fan applied to an extreme environment, which comprises a passive yawing mechanical structure, the passive yawing mechanical structure comprises a tail vane and a vertical shaft which are fixed on a cabin, the tail vane is fixedly connected to the tail of the cabin and comprises a tail vane rod and a tail vane plate, the tail vane rod is inclined relative to the main axis of a generator, and the tail vane plate is positioned at the tail end of the tail vane rod; the vertical shaft is fixedly mounted on one side of the cabin and is biased relative to the main axis of the generator; and the passive variable-pitch mechanical structure comprises centrifugal flying rods arranged on blade handles of the blades and a synchronous variable-pitch mechanism installed in a closed space formed by the hub, the flow guide cover and the blades, and the synchronous variable-pitch mechanism is arranged to be capable of achieving simultaneous variable pitch on the blades under driving of the centrifugal flying rods. According to the utility model, in an extreme environment, through the adjustment of two sets of passive mechanical structures, the dependence on an electric control system is reduced, and stable and continuous power output can still be realized after the storage battery is fully charged; and the synchronous variable pitch mechanism is accommodated in the closed space, so that the service life and the safety of the equipment are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of wind power generators, in particular to a small wind turbine used in extreme environments. Background Art

[0002] The construction of scientific research stations in the Antarctic and Arctic is a national strategy. With the increasing number of scientific research stations built in my country in Antarctica, the supply of green electricity in Antarctica has also been included in the focus of attention. However, the meteorological environment in Antarctica is very harsh, with strong ultraviolet rays, low ambient temperature, and abnormally good wind resources, making the construction conditions of the project extremely difficult. Under such environmental conditions as the Antarctic scientific research station, there is a demand for a mobile container functional unit that combines small wind turbines and photovoltaic panels. The specific requirements for wind turbines are simple and safe structure, light machine, simple control system, continuous output after the battery is fully charged, and strong resistance to extreme wind speeds for wind turbines.

[0003] Currently, most of the small wind turbines with a power of about 2kW on the market are falsely labeled and of varying quality. The target customers and target market for small-power wind turbines like 2kW have already determined the configuration of such wind turbines (the cut-out wind speed is about level 8). They are usually used in areas with average wind resources, and there are basically no products that can be used in the Antarctic region.

[0004] At present, the protection measures for speed and power limitation of small wind turbines on the market are mostly side-biased tail rudders, and some are gravity-adaptive tail rudders. Regardless of whether the tail rudder is side-biased or gravity-adaptive, it is difficult for the impeller to face the wind at 90° under extreme wind speed conditions (here, the tail rudder structure affects the angle between the impeller and the wind direction. The side-biased tail rudder or gravity-adaptive deflection of the tail rudder will cause the impeller to have an angle to the wind, and the greater the wind speed, the greater the angle of the impeller's deviation from the wind direction, the smaller the windward surface of the impeller, and the lower the energy absorbed by the impeller. It has a certain effect in limiting the speed and power, but as the wind speed continues to increase, the structure of the tail rudder determines that the impeller cannot effectively approach 90°. After exceeding a certain wind speed, the absorption rate of the impeller will increase rapidly with the increase in wind speed, and there are limitations in limiting the speed and power in the high wind speed section). In other words, under extreme wind speed conditions, small wind turbines may have overspeed and overpressure, which may lead to accidents such as burning the motor or burning the control.

[0005] Moreover, most of the blades of small wind turbines currently on the market are fixed pitch. Although some foreign countries use highly elastic flexible blades or special elastic materials at the root of the blades to achieve the effect of passive variable pitch power limit under wind force, it remains to be seen whether they are still durable under high ultraviolet and extreme cold conditions. In other words, small wind turbines currently on the market cannot limit speed and power through passive variable pitch.

[0006] Although wind turbine manufacturers with high safety requirements generally equip the machine with a main shaft mechanical brake, the machine will shut down once the wind speed increases. Frequent shutdowns in such extreme environments make it difficult for the wind turbine to continue to work and output electricity, and the electronic system of the wind turbine controller is prone to failure. In addition, most small wind turbine controllers on the market have relatively weak anti-interference and anti-overload capabilities due to cost and universality considerations. Utility Model Content

[0007] In order to overcome the above problems, the utility model provides a small wind fan for use in extreme environments, which can ensure the safety and stable output of electricity of the small wind fan in extreme environments.

[0008] To this end, according to one aspect of the utility model, a small wind turbine for use in extreme environments is provided, comprising an impeller and a nacelle, wherein the impeller comprises a hub, a shroud and a plurality of blades, and a generator is disposed in the nacelle, and the small wind turbine is characterized in that it also comprises:

[0009] A passive yaw mechanical structure, comprising a tail rudder fixed to the nacelle and a vertical shaft, wherein the tail rudder is fixedly connected to the tail of the nacelle and comprises a tail rudder bar obliquely offset relative to the main axis of the generator and a tail rudder plate located at the end of the tail rudder bar, and the vertical shaft is fixedly installed on one side of the nacelle and offset relative to the main axis of the generator; and

[0010] A passive pitch control mechanical structure includes a centrifugal fly rod arranged on the petiole of each blade and a synchronous pitch control mechanism installed in a closed space formed by a hub, a fairing and the blades. The synchronous pitch control mechanism is configured to achieve simultaneous pitch control of each blade under the drive of each centrifugal fly rod.

[0011] In the utility model, through dual passive mechanical structures, namely, through passive yaw mechanical structure and passive pitch mechanical structure, it is possible to ensure that the small wind turbine can function independently in extreme environments through its own mechanical structure adjustment by adjusting the wind angle of the impeller and realizing blade pitch respectively, and can still output power stably and continuously even after the battery of the small wind turbine is fully charged; by designing the synchronous pitch mechanism to be accommodated in the closed space formed by the hub, the fairing and the blades, the synchronous pitch mechanism does not need to be exposed to extreme environments, reducing the damage to the various components of the mechanism caused by extreme weather (including strong winds, dust, low temperature, high ultraviolet rays, etc.), and improving the service life and equipment safety; through the use of dual passive mechanical structures, the use of electronic control systems is reduced, so that the electronic control system of the small wind turbine can be further simplified, greatly reducing the probability of control failure in extreme environments, and further ensuring the safety and stability of the small wind turbine.

[0012] Furthermore, the synchronous pitch mechanism includes a guide shaft, a synchronous disk, a low-temperature spring, and adjustable pull rods and cranks whose number is equivalent to that of the centrifugal fly rods, wherein the guide shaft is coaxially fixed to the wheel hub and is provided with an annular shoulder and an axial long hole, the synchronous disk is sleeved on the guide shaft and can move axially along the axial long hole between two extreme positions via a guide bolt, the low-temperature spring is sleeved on the guide shaft between the annular shoulder and the synchronous disk, and each adjustable pull rod is provided with joint bearings at both ends, one of the joint bearings is rotatably connected to the synchronous disk via a first pull rod pin, and the other joint bearing is rotatably connected to one end of the crank via a second pull rod pin, and the other end of the crank is fixedly connected to the petiole shaft of the petiole, and wherein the petiole shaft is rotatably mounted on the wheel hub via an mounting bearing.

[0013] Through the above-mentioned structural setting, the synchronous variable pitch mechanism has a simple structure, is compact and reliable, and is easy, convenient and effective to install, while realizing a lightweight design of the whole machine; through the above-mentioned centrifugal variable pitch structure, the installation angle of the blade changes as the impeller speed increases, the Cp value of the blade decreases, and the impeller absorption capacity decreases, thereby achieving the purpose of limiting speed and power.

[0014] Furthermore, the petiole shaft and the other end of the crank are matched with a square shaft and a square hole.

[0015] Through the above structural cooperation, the other end of the crank is fixed relative to the petiole axis.

[0016] Furthermore, the other end of the crank is further fixed to the petiole shaft through a round nut at the inner end of the petiole shaft, wherein the round nut is a low-temperature alloy steel round nut and the petiole shaft is a low-temperature alloy steel petiole shaft.

[0017] The above-mentioned structural setting further ensures the fixation of the crank on the blade shaft; the setting of the low-temperature alloy steel round nut and the low-temperature alloy steel blade shaft enables the small fan to be effectively used in extreme environments, especially in extremely cold environments.

[0018] Furthermore, the blades are UV low-temperature resin-based carbon fiber blades, the fairing is a UV low-temperature resin-based carbon fiber fairing, and the tail rudder plate is a UV low-temperature resin-based carbon fiber tail rudder plate; the nacelle is an aviation aluminum machined nacelle, the wheel hub is an aviation aluminum machined hub, the generator shell is an aviation aluminum machined shell; and the tail rudder rod is a 316 stainless steel welded rod.

[0019] Through the above-mentioned structural arrangement, the small-sized fan of the utility model can better meet the requirements of special use environments, namely, it is cold-resistant and UV-resistant, and is lightweight and easy to install.

[0020] Furthermore, the tail rudder rod is inclined by 12° relative to the main axis of the generator; and the vertical shaft is offset by 80 mm relative to the main axis of the generator.

[0021] Through the above-mentioned arrangement, the impeller can be effectively angled to the wind direction, thereby limiting the impeller's ability to absorb wind energy. Within a certain wind speed range, a certain effect of limiting power and speed can be achieved. In other words, the structural arrangement ensures that at low wind speeds, the impeller is facing the wind to ensure more power generation in low winds. At high wind speeds, the impeller is facing the wind direction sideways, and the impeller's windward area is reduced to absorb energy to achieve the purpose of limiting power in high winds.

[0022] Furthermore, the passive yaw mechanical structure is arranged so that before the wind speed reaches 18m / s, the torque of the impeller relative to the vertical axis and the torque of the tail rudder plate relative to the vertical axis can reach a dynamic balance; the passive variable pitch mechanical structure is arranged to start working after the wind speed reaches 18m / s, and can ensure that the small wind turbine can continuously and stably output power before the wind speed reaches 36m / s.

[0023] Through the above settings, the passive yaw mechanical structure and the passive variable pitch mechanical structure form an effective connection in the operation sequence, and the passive variable pitch mechanical structure takes effect later in the sequence, which makes up for the defect that the vertical axis offset and the lateral offset of the tail rudder of the passive yaw mechanical structure can no longer work alone in strong winds. The two passive structures complement each other and make the maximum use of the idea of ​​mechanical structure power limitation, and finally realize that after the battery is fully charged, the whole machine also needs the wind turbine to continuously output power to other power-consuming equipment on the site. The wind turbine can also stand alone outside the electronic control system by relying on its own mechanical structure adjustment, ensuring that the wind turbine can output power safely and stably before the wind speed reaches 12 levels, which is far beyond the working limit of conventional wind turbines.

[0024] Furthermore, the passive yaw mechanical structure is arranged so that when the wind speed is between 3 and 6 m / s, the torque of the impeller relative to the vertical axis and the torque of the tail rudder plate relative to the vertical axis reach a balance, and the angle between the rotation axis centerline of the impeller and the wind direction is maintained at 0°; in the process of the wind speed gradually increasing from 6 m / s to 18 m / s, the angle formed by the rotation axis centerline of the impeller and the wind direction gradually increases, the windward area of ​​the tail rudder plate gradually increases, and the torque of the impeller relative to the vertical axis and the torque of the tail rudder plate relative to the vertical axis automatically achieve multiple dynamic balances in this process.

[0025] Furthermore, the above-mentioned small wind turbine used in extreme environments also includes a main shaft braking mechanism that is activated after the wind speed reaches 36m / s, wherein the generator has a low-temperature alloy steel main shaft, and the main shaft braking mechanism includes a brake magnetic suction cup, a brake rotating disc with a friction plate, a stainless steel 316 gap sleeve, and a stainless steel 316 round nut, wherein the brake magnetic suction cup is installed on the rear end plate of the generator, the brake rotating disc is axially movably installed on the low-temperature alloy steel main shaft through a key, the stainless steel 316 gap sleeve is sleeved on the low-temperature alloy steel main shaft at the gap between the brake magnetic suction cup and the brake rotating disc, and the stainless steel 316 round nut is fastened to the low-temperature alloy steel main shaft at the rear end of the brake rotating disc to limit the brake rotating disc from moving backward and separating from the low-temperature alloy steel main shaft. When the brake magnetic suction cup is energized, an electromagnetic force is generated to cause the friction plate and the entire brake rotating disc to move axially forward, so that the friction plate contacts the brake magnetic suction cup to generate a huge friction torque, causing the low-temperature alloy steel main shaft to stop rotating to stop the small wind turbine.

[0026] Through the above-mentioned structural setting, when the power limiting capacity of the dual passive mechanical mechanism reaches the limit and an overpressure and overpower alarm occurs in the small fan, the small fan will start the main shaft brake (that is, the fan control system will receive the alarm information and start the main shaft brake), and stop the fan to ensure that the electrical system and mechanical structure of the fan can safely pass through wind speeds above level 12.

[0027] These and other aspects of the present invention will be more clearly explained by referring to the embodiments described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The structure and further objects and advantages of the present invention will be better understood through the following description in conjunction with the accompanying drawings, in which the same reference numerals identify the same elements:

[0029] Figure 1 This is a schematic diagram of the external structure of a small-sized fan used in extreme environments viewed from top to bottom according to a specific implementation of the utility model;

[0030] Figure 2 yes Figure 1 The schematic diagram of the external structure of a small fan used in extreme environments as seen from the front to the back is shown;

[0031] Figure 3 yes Figure 2 A schematic plan view of the structure of a small fan used in extreme environments after the guide cover is removed and the blades are cut off;

[0032] Figure 4 yes Figure 3 The structure shown is a plan view cut along line AA;

[0033] Figure 5 yes Figure 4 A three-dimensional schematic diagram of the structure shown;

[0034] Figure 6 yes Figure 3 A partial perspective schematic diagram of the structure shown cut off at the junction of the crank and the petiole axis;

[0035] Figure 7 yes Figure 1 The figure is a three-dimensional cross-sectional schematic diagram of the structure related to the main shaft brake mechanism of a small fan used in extreme environments. DETAILED DESCRIPTION

[0036] The specific embodiments of the present invention will be described below in conjunction with the accompanying drawings. However, it should be understood that the embodiments disclosed herein are only typical examples of the present invention, which can be embodied in various forms. Therefore, the specific details disclosed herein are not considered to be restrictive, but only as a basis for the claims and as a representative basis for teaching those skilled in the art to apply the present invention differently in any appropriate manner in practice.

[0037] like Figures 1 to 7 As shown, according to a specific embodiment of the utility model, a small wind turbine for use in extreme environments includes an impeller 100 and a nacelle 300, wherein the impeller 100 includes a hub 101, a shroud 103 and a plurality of blades 105, and a generator 301 is disposed in the nacelle 300. The utility model is characterized in that it also includes a passive pitch-changing mechanical structure 1 and a passive yaw mechanical structure 3, wherein the passive yaw mechanical structure 3 includes a tail rudder 30 and a vertical shaft 31 fixed to the nacelle 300, wherein the passive pitch-changing mechanical structure 1 includes a centrifugal fan 106 disposed on the petiole 115 of each blade 105. The centrifugal fly rod 15 and the synchronous pitch mechanism 10 installed in the closed space 113 formed by the hub 101, the fairing 103 and the blades 105, the synchronous pitch mechanism 10 is configured to achieve simultaneous pitch change of each blade 105 under the drive of each centrifugal fly rod 15; the tail rudder 30 is fixedly connected to the tail of the cabin 300, and includes a tail rudder rod 33 obliquely offset relative to the main axis X1 of the generator 301 and a tail rudder plate 35 located at the end of the tail rudder rod 33, and the vertical shaft 31 is fixedly installed on one side of the cabin 300 and offset relative to the main axis X1 of the generator 301.

[0038] By superimposing the two sets of mechanical power limiting measures, namely the passive pitch mechanical structure 1 and the passive yaw mechanical structure 3, the wind turbine can continue to output, ensuring that the wind turbine does not exceed the voltage and power output when the level is less than or equal to 12, reducing the dependence on the electrical control system, and ensuring the safe and stable operation of the whole machine from the root.

[0039] For example Figures 3 to 6As shown, in this embodiment, the synchronous pitch mechanism 10 includes a guide shaft 11, a synchronous disk 13, a low-temperature spring 14, an adjustable pull rod 17 and a crank 19 whose number is equal to that of the centrifugal fly rod 15, wherein the guide shaft 11 is coaxially fixed to the hub 101, and is provided with an annular shoulder 110 and an axial long hole 112; the synchronous disk 13 is sleeved on the guide shaft 11, and can move axially between two extreme positions along the axial long hole 112 via the guide bolt 12; the low-temperature spring 14 is on the annular shoulder 110 The guide shaft 11 is sleeved between the centrifugal flying rod 15 and the synchronous disk 13, and joint bearings 16 are installed at both ends of each adjustable pull rod 17, one of the joint bearings 16 is rotatably connected to the synchronous disk 13 via the first pull rod pin 18, and the other joint bearing 16 is rotatably connected to one end 191 of the crank 19 via the second pull rod pin 18, and the other end 192 of the crank 19 is fixedly connected to the petiole shaft 125 of the petiole 115, and the petiole shaft 125 is rotatably mounted on the hub 101 via the mounting bearing 135. When the centrifugal flying rod 15 is affected by the increase in speed, the torque acting on the petiole 115 will gradually increase, and the torque will eventually be transmitted to the crank 19, thereby transmitting the motion to the synchronous disk 13 via the adjustable pull rod 17, and realizing the synchronous pitch action of the three blades 105.

[0040] It should be understood that the synchronous disk 13 can only make reciprocating linear motion along the guide shaft 11, and the rear end surface of the synchronous disk 13 acts with the low temperature spring 14 to store elastic potential energy. Specifically, as the speed of the centrifugal fly rod 15 continues to increase, the torque becomes larger and larger, which will cause the blade 105 to change the pitch angle to a larger extent, causing the Cp (wind energy utilization coefficient) of the impeller 100 to drop rapidly as the speed increases, and the impeller absorbs energy and also drops accordingly. As the petiole 115 twists more, the adjustable pull rod 17 will drive the synchronous disk 13 to compress the low temperature spring 14 more, thereby causing the low temperature spring 14 to store more elastic potential energy, that is, the low temperature spring 14 has a greater elastic force, and the elastic force and the force of the centrifugal fly rod 15 on the low temperature spring 14 through the synchronous disk 13 reach an adaptive balance under the action of the impeller speed.

[0041] like Figure 6 As shown, in this embodiment, the blade stalk shaft 125 and the other end 192 of the crank 19 are square shaft and square hole. Figure 4 and Figure 5 As shown, the other end 192 of the crank 19 is further fixed to the petiole shaft 125 through a round nut 145 at the inner end of the petiole shaft 125, wherein the round nut 145 is a low-temperature alloy steel round nut, and the petiole shaft 125 is a low-temperature alloy steel petiole shaft.

[0042] It should be noted that in this embodiment, the blade 105 is a UV low temperature resin based carbon fiber blade, the shroud 103 is a UV low temperature resin based carbon fiber shroud, the tail rudder plate 35 is a UV low temperature resin based carbon fiber tail rudder plate; the nacelle 300 is an aviation aluminum machined nacelle, the hub 101 is an aviation aluminum machined hub, the shell of the generator 301 is an aviation aluminum machined shell; the tail rudder rod 33 is a 316 stainless steel welded rod. These lightweight designs greatly meet the requirements of small wind turbines for cold resistance, UV resistance and easy installation in special use environments.

[0043] For example Figure 1 As shown, in this embodiment, the tail rudder bar 33 is inclined by 12° (indicated by A1 in the figure) relative to the main axis X1 of the generator 301; the vertical shaft 31 is offset by 80mm (indicated by D1 in the figure) relative to the main axis X1 of the generator 301. Through the above arrangement, the impeller 100 can be effectively angled with the wind direction to limit the ability of the impeller to absorb wind energy, and a certain effect of limiting power and speed can be achieved within a certain wind speed range. In other words, the structural arrangement ensures that the impeller 100 faces the wind at low wind speeds to ensure more power generation in low winds, and the impeller faces the wind direction at high wind speeds, and the windward area of ​​the impeller is reduced to absorb energy to achieve the purpose of high wind power limit.

[0044] Furthermore, the passive variable pitch mechanical structure 1 is configured to start working after the wind speed reaches 18 m / s, and can ensure that the small wind turbine can continuously and stably output power before the wind speed reaches 36 m / s; the passive yaw mechanical structure 3 is configured so that before the wind speed reaches 18 m / s, the torque of the impeller 100 relative to the vertical shaft 31 and the torque of the tail rudder plate 35 relative to the vertical shaft 31 can reach a dynamic balance. Furthermore, in the present embodiment, the passive yaw mechanical structure 3 is configured so that when the wind speed is between 3 and 6 m / s, the moment of the impeller 100 relative to the vertical shaft 31 and the moment of the tail rudder plate 35 relative to the vertical shaft 31 reach a balance, and the rotation axis X1 of the impeller 100 maintains an angle of 0° with the wind direction; in the process of the wind speed gradually increasing from 6 m / s to 18 m / s, the angle formed by the rotation axis X1 of the impeller 100 and the wind direction gradually increases, and the windward area of ​​the tail rudder plate 35 gradually increases, and the moment of the impeller 100 relative to the vertical shaft 31 and the moment of the tail rudder plate 35 relative to the vertical shaft 31 automatically achieve multiple dynamic balances in this process.

[0045] It should be noted that, during the setting process of the passive yaw mechanical structure 3, for example, by adjusting the offset distance of the vertical shaft 31 relative to the main axis X1 of the generator 301, the area of ​​the tail rudder plate 35, the distance from the tail rudder plate 35 (to be precise, the aerodynamic center of the tail rudder) to the vertical shaft 31, the impeller area, the distance from the impeller center to the vertical shaft 31, etc., multiple dynamic balances of the moment of the impeller 100 relative to the vertical shaft 31 and the moment of the tail rudder plate 35 relative to the vertical shaft 31 before the wind speed reaches 18m / s can be achieved. Of course, the vertical shaft rotation friction moment can also be taken into account, but if the vertical shaft rotation friction moment is taken into account, it is necessary to set the above three moments to achieve dynamic balance.

[0046] Specifically, by setting the passive yaw mechanical structure 3, when the wind speed is 3-6 m / s, the impeller 100 is in a relatively low rotation speed range, the flow velocity reduction ratio after the wind flows through the wind rotor 100 is relatively small, the wind thrust obtained at the tail rudder plate 35 is relatively small, and the rotating disk of the impeller 100 is also subjected to wind thrust, and these two forces form two opposite moments relative to the axis of the vertical shaft 31 (if the vertical shaft rotation friction moment is taken into account, there are three moments; it should be noted that the vertical shaft 31 is fixed to the nacelle 300 as a whole component, but the central axis of the vertical shaft 31 (not shown) is rotatable relative to the nacelle 300, thereby generating a vertical shaft rotation friction moment), these two moments can be basically balanced on the vertical shaft 31 at a wind speed of 3-6 m / s, and the impeller 100 basically maintains an angle of 0° with the wind direction, that is, the impeller absorbs the wind energy in the impeller swept area to the maximum extent;

[0047] As the wind speed increases, the impeller speed increases, the impeller's rotating disk obtains a greater thrust, and the ratio of the velocity reduction after the wind flows through the impeller's rotating disk gradually increases. Then, the impeller wake flows toward the tail rudder plate 35, and the force acting on the tail rudder plate will decrease. Then, these two moments (the moment of the impeller on the vertical axis, the moment of the tail rudder plate on the vertical axis) (or three moments: the moment of the impeller on the vertical axis, the moment of the tail rudder plate on the vertical axis, and the friction moment of the vertical axis) break the balance on the vertical axis, and the impeller's rotating axis will form an angle with the wind direction. The impeller's windward area will decrease, and the tail rudder plate's windward area will increase accordingly. These two moments or three moments will re-establish balance on the vertical axis.

[0048] As the wind speed increases further, when the angle between the impeller rotation axis and the wind direction further increases, the tail rudder plate 35 is no longer affected by the impeller wake, and the moment of the tail rudder plate relative to the vertical axis increases, and these two moments or these three moments will reach a balance again;

[0049] When the wind speed reaches 18m / s, the angle between the impeller rotation axis and the wind direction further expands to about 77°. At this time, the tail rudder plate 35 has reached the maximum windward area. When the wind speed increases further, if the small wind turbine only has the passive yaw mechanical structure 3, it will fall into an unstable state. That is to say, after the wind speed reaches 18m / s, the passive yaw mechanical structure 3 completes its mission.

[0050] After the wind speed reaches and exceeds 18m / s, the wind energy on the rotating disk of the impeller increases, and the system of the small wind turbine cannot absorb so much energy. The performance of the impeller is that the speed will increase. After the speed increases, the passive variable pitch mechanical structure 1 is activated. The increase in speed causes the centrifugal flying rod 15 to spontaneously adjust the installation angle of the blade 105. The change in the installation angle of the blade actually affects the angle (i.e., the angle of attack) at which the airflow cuts into the airfoil. According to the aerodynamic theory of the airfoil, the Cp and Ct values ​​of the blade airfoil will change with the change of the angle of attack. The Cp value of the airfoil is controlled within a certain limit, and the energy absorbed by the impeller finally does not exceed 1.5 times the rated power. The reduction in the Ct value will reduce the thrust of the wind acting on the impeller, thereby reducing the torque of the impeller 100 relative to the vertical shaft 31, so that the passive yaw mechanical structure 3 can make the impeller stable again from an unstable state at high wind speeds.

[0051] Since the passive variable pitch mechanical structure 1 and the passive yaw mechanical structure 3 belong to different technical routes in terms of power limiting mechanism, the time of spontaneous adjustment access is also different, and no electronic control logic is required for manipulation. The two passive structures can be seamlessly connected only through mechanical structure design and coordination, such as through the design of counterweight, K coefficient of low-temperature spring 14, length of centrifugal fly rod 15, etc., and can also be combined with the characteristic curve of the airfoil.

[0052] like Figure 7As shown, in this embodiment, the small wind turbine also includes a main shaft brake mechanism 5 that is activated after the wind speed reaches 36m / s, wherein the generator 301 has a low-temperature alloy steel main shaft 311, and the main shaft brake mechanism 5 includes a brake magnetic suction cup 51, a brake rotating disc 53 with a friction plate (not shown), a stainless steel 316 gap sleeve 55, and a stainless steel 316 round nut 57, wherein the brake magnetic suction cup 51 is installed on the rear end plate 321 of the generator 301, the brake rotating disc 53 is axially movably installed on the low-temperature alloy steel main shaft 311 through a key, the stainless steel 316 gap sleeve 55 is sleeved on the low-temperature alloy steel main shaft 311 at the gap between the brake magnetic suction cup 51 and the brake rotating disc 53, and the stainless steel 316 round nut 57 is fastened to the low-temperature alloy steel main shaft 311 at the rear end of the brake rotating disc 53, thereby limiting the brake rotating disc 53 from moving backward and disengaging from the low-temperature alloy steel main shaft 311. When the brake magnetic suction cup 51 is energized, an electromagnetic force is generated to cause the friction plate and the entire brake rotating disc 53 to move axially forward, so that the friction plate contacts the brake magnetic suction cup 51 to generate a huge friction torque, causing the low-temperature alloy steel main shaft 311 to stop rotating, thereby stopping the small fan.

[0053] That is to say, when the passive pitch mechanical structure 1 and the passive yaw mechanical structure 3 reach their power limiting capacity, and when an overpressure and overpower alarm occurs in the small wind turbine, the small wind turbine will activate the main shaft braking mechanism 5 to stop the small wind turbine to ensure that the electrical system and mechanical structure of the wind turbine can safely pass through wind speeds above level 12.

[0054] The technical content and technical features of the utility model have been disclosed above, but it can be understood that under the creative idea of ​​the utility model, those skilled in the art can make various changes and improvements to the above structure, including the combination of technical features disclosed or claimed separately here, and other combinations that obviously include these features. These deformations and / or combinations all fall within the technical field involved in the utility model and fall within the protection scope of the claims of the utility model.

Claims

1. A small wind turbine used in extreme environments, comprising an impeller and a nacelle, wherein the impeller comprises a hub, a shroud and a plurality of blades, and a generator is placed in the nacelle, characterized in that Also includes: A passive yaw mechanical structure, comprising a tail rudder fixed to the nacelle and a vertical shaft, wherein the tail rudder is fixedly connected to the tail of the nacelle and comprises a tail rudder bar obliquely offset relative to the main axis of the generator and a tail rudder plate located at the end of the tail rudder bar, and the vertical shaft is fixedly installed on one side of the nacelle and offset relative to the main axis of the generator; and A passive pitch control mechanical structure includes a centrifugal fly rod arranged on the petiole of each blade and a synchronous pitch control mechanism installed in a closed space formed by a hub, a fairing and the blades. The synchronous pitch control mechanism is configured to achieve simultaneous pitch control of each blade under the drive of each centrifugal fly rod.

2. The small fan for use in extreme environments according to claim 1 is characterized in that: The synchronous variable pitch mechanism includes a guide shaft, a synchronous disk, a low-temperature spring, and adjustable pull rods and cranks whose number is equal to that of the centrifugal fly rods, wherein the guide shaft is coaxially fixed to the wheel hub and is provided with an annular shoulder and an axial long hole, the synchronous disk is sleeved on the guide shaft and can move axially between two extreme positions along the axial long hole via a guide bolt, the low-temperature spring is sleeved on the guide shaft between the annular shoulder and the synchronous disk, and each adjustable pull rod is provided with joint bearings at both ends, one of the joint bearings is rotatably connected to the synchronous disk via a first pull rod pin, and the other joint bearing is rotatably connected to one end of the crank via a second pull rod pin, and the other end of the crank is fixedly connected to the petiole shaft of the petiole, and wherein the petiole shaft is rotatably mounted on the wheel hub via an mounting bearing.

3. The small fan for use in extreme environments according to claim 2 is characterized in that: The petiole shaft and the other end of the crank are matched with each other in the form of a square shaft and a square hole.

4. The small fan for use in extreme environments according to claim 3 is characterized in that: The other end of the crank is further fixed to the petiole shaft through a round nut at the inner end of the petiole shaft, wherein the round nut is a low-temperature alloy steel round nut, and the petiole shaft is a low-temperature alloy steel petiole shaft.

5. The small fan for use in extreme environments according to claim 1 is characterized in that: The blades are UV low-temperature resin-based carbon fiber blades, the fairing is a UV low-temperature resin-based carbon fiber fairing, and the tail rudder plate is a UV low-temperature resin-based carbon fiber tail rudder plate; the nacelle is an aviation aluminum machined nacelle, the wheel hub is an aviation aluminum machined hub, and the generator shell is an aviation aluminum machined shell; the tail rudder rod is a 316 stainless steel welded rod.

6. The small fan for use in extreme environments according to claim 1, characterized in that: The tail rudder rod is inclined by 12° relative to the main axis of the generator; and the vertical shaft is offset by 80 mm relative to the main axis of the generator.

7. The small wind turbine for use in extreme environments according to any one of claims 1 to 6, characterized in that: The passive yaw mechanical structure is configured so that before the wind speed reaches 18m / s, the torque of the impeller relative to the vertical shaft and the torque of the tail rudder plate relative to the vertical shaft can reach a dynamic balance; the passive variable pitch mechanical structure is configured to start working after the wind speed reaches 18m / s and can ensure that the small wind turbine can continuously and stably output power before the wind speed reaches 36m / s.

8. The small fan for use in extreme environments according to claim 7, characterized in that: The passive yaw mechanical structure is configured such that when the wind speed is between 3 and 6 m / s, the moment of the impeller relative to the vertical shaft and the moment of the tail rudder plate relative to the vertical shaft reach a balance, and the rotation axis centerline of the impeller and the wind direction maintain an angle of 0°; in the process of the wind speed gradually increasing from 6 m / s to 18 m / s, the angle formed by the rotation axis centerline of the impeller and the wind direction gradually increases, the windward area of ​​the tail rudder plate gradually increases, and the moment of the impeller relative to the vertical shaft and the moment of the tail rudder plate relative to the vertical shaft automatically achieve multiple dynamic balances in this process.

9. The small fan for use in extreme environments according to claim 7, characterized in that: It also includes a main shaft braking mechanism that is activated after the wind speed reaches 36m / s, wherein the generator has a low-temperature alloy steel main shaft, and the main shaft braking mechanism includes a brake magnetic suction cup, a brake rotating disc with a friction plate, a stainless steel 316 gap sleeve, and a stainless steel 316 round nut, wherein the brake magnetic suction cup is installed on the rear end plate of the generator, the brake rotating disc is axially movably installed on the low-temperature alloy steel main shaft through a key, the stainless steel 316 gap sleeve is sleeved on the low-temperature alloy steel main shaft at the gap between the brake magnetic suction cup and the brake rotating disc, and the stainless steel 316 round nut is fastened to the low-temperature alloy steel main shaft at the rear end of the brake rotating disc to limit the brake rotating disc from moving backward and separating from the low-temperature alloy steel main shaft. When the brake magnetic suction cup is energized, an electromagnetic force is generated to cause the friction plate and the entire brake rotating disc to move axially forward, so that the friction plate contacts the brake magnetic suction cup to generate a huge friction torque, causing the low-temperature alloy steel main shaft to stop rotating to stop the small fan.

10. The small fan for use in extreme environments according to any one of claims 1 to 6, characterized in that It also includes a main shaft braking mechanism that is activated after the wind speed reaches 36m / s, wherein the generator has a low-temperature alloy steel main shaft, and the main shaft braking mechanism includes a brake magnetic suction cup, a brake rotating disc with a friction plate, a stainless steel 316 gap sleeve, and a stainless steel 316 round nut, wherein the brake magnetic suction cup is installed on the rear end plate of the generator, the brake rotating disc is axially movably installed on the low-temperature alloy steel main shaft through a key, the stainless steel 316 gap sleeve is sleeved on the low-temperature alloy steel main shaft at the gap between the brake magnetic suction cup and the brake rotating disc, and the stainless steel 316 round nut is fastened to the low-temperature alloy steel main shaft at the rear end of the brake rotating disc to limit the brake rotating disc from moving backward and separating from the low-temperature alloy steel main shaft. When the brake magnetic suction cup is energized, an electromagnetic force is generated to cause the friction plate and the entire brake rotating disc to move axially forward, so that the friction plate contacts the brake magnetic suction cup to generate a huge friction torque to stop the low-temperature alloy steel main shaft to stop the small fan.

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