Vertical windmill system and wind power generation system

Abstract

The invention relates to vertical wind motor system and wind power generation system. The vertical wind motor system is provided with longitudinal fan shaft, and the fan shaft is provided with wind drum for starting and wind wheel for high-speed rotation. The wind wheel is composed of four blades which are distributed at equal angle intervals on the fan shaft. The wind drum is located inside the wind wheel and has one or more. The multiple wind drums are sequentially distributed on the longitudinal shaft and form an integrated wind power rotation system with the wind wheel. The vertical span of the wind drum is consistent with the vertical span of the middle part of the space inside the wind wheel. The wind motor of the vertical wind power generation system adopts the above-mentioned vertical wind motor system, the generator adopts vertical outer rotor generator, and the outer rotor motor is connected with the rotor system composed of the wind wheel and the blade wind drum. The invention can realize low wind speed self-starting of the wind motor, improve the stability of high-speed operation of the wind motor, reduce vibration and noise, and optimize the output characteristics.

Description

Technical Field

[0001] This invention relates to a vertical wind turbine system and a vertical wind power generation system employing such a vertical wind turbine system. Background Technology

[0002] A wind turbine (or wind power machine) is a device in a wind power generation system that converts wind energy into rotational mechanical energy. Based on its shaft setting / attitude, it can be mainly divided into two types: horizontal axis and vertical axis. Among them, the vertical axis wind turbine is not affected by the wind direction and does not require a yaw system. In certain situations, especially in areas with relatively low wind speeds, it has a strong advantage.

[0003] Vertical axis wind turbines can be mainly divided into two types: drag-type and lift-type. A typical example of a drag-type wind turbine is the Savonius turbine, where the rotor's rotation is driven by the pressure difference created by the airflow in front of and behind the blades. Because drag-type wind turbines generate a large reverse torque in the upwind region, their wind energy utilization rate is low, limiting their application. Currently, lift-type wind turbines are more widely used, with the Darrieus turbine being a typical example. Some even consider all lift-type vertical axis wind turbines to belong to the Darrieus type. The Darrieu wind turbine is the earliest lift-type vertical axis wind turbine, invented by an engineer named G.J. M. Darrieus. It was patented in 1931, but did not receive much attention until extensive research by the Canadian National Aerodynamics Laboratory and Sandia National Laboratories in the United States. The Darrieu wind turbine then gained practical value. It is said that the Darrieu wind turbine has the highest wind energy utilization coefficient compared to all other vertical axis wind turbines.

[0004] To achieve better performance, continuous improvements have been made to the classic Darrieus wind turbine. For example, Chinese patent document CN106032791A discloses a lift-complementary vertical axis wind turbine, which consists of a wind turbine, a disc generator, a main shaft, and connecting parts. The wind turbine is a combined wind turbine, combining a Savonius-type wind turbine and a Darrieus-type wind turbine. The Savonius-type wind turbine includes two micro-S-shaped blades and upper and lower circular support plates for fixing the blades. The two micro-S-shaped blades are distributed parallel to each other on the circular support plates and are centrally symmetrical about the central axis of the wind turbine. The outer surface of each of the upper and lower circular support plates has four reinforcing ribs, forming a 90° angle with each other. The Darrieus-type wind turbine is a Darrieus-type φ-shaped wind turbine, which uses three arc-shaped plates as its blades. The arc-shaped plates include a circular arc section in the middle and straight sections at both ends of the circular arc section. This combination takes advantage of the two types of wind turbines, achieves self-starting at low wind speeds, and improves power generation efficiency. For example, Chinese patent document CN115539294A discloses a wind-solar supplementary vertical axis wind turbine generator set, including an impeller assembly and a support column for mounting the impeller assembly. The blades of the impeller assembly are attached to photovoltaic panels, and the blades are roughly in the shape of a vertical arc, with three blades evenly distributed. A conductive collar is provided below the impeller assembly, and the conductive collar is installed on the support column to electrically connect the photovoltaic panels to the battery. This utilizes both wind and solar energy sources, improving the power supply capacity and stability.

[0005] In the embodiments defined or provided by these prior art, the Darrieus wind turbine has three blades, evenly distributed at 120° intervals (angular distance). This is the commonly used blade arrangement for Darrieus wind turbines in practice, and this number and arrangement of blades can achieve good results when there are no other structures interfering with the airflow. However, when other structures interfere with the airflow, it may cause other problems. For example, in the aforementioned technical solution disclosed in CN106032791A, because the Savonius wind turbine blocks the wind flowing through the Darrieus wind turbine, the magnitude and direction of the wind force experienced by the blades on the windward and leeward sides may be significantly different, affecting the stability of the Darrieus wind turbine operation, leading to increased vibration and noise, and also adversely affecting the mechanical energy output characteristics of the wind turbine and the electrical energy output characteristics of the generator. Summary of the Invention

[0006] To overcome the aforementioned deficiencies of the prior art, the present invention provides a vertical wind turbine system and a vertical wind power generation system using such a vertical wind turbine system, so as to improve the stability of wind turbine operation, reduce vibration and noise, and optimize output characteristics while realizing the self-starting of the wind turbine / wind power generation system at low wind speeds.

[0007] The technical solution of the present invention is as follows: a vertical wind turbine system (hereinafter referred to as a vertical wind turbine, or wind turbine) is provided with a longitudinal (usually vertical in use) wind turbine shaft. The wind turbine shaft is equipped with a wind duct (e.g., a Savonius wind duct, or a Savonius wind turbine) composed of arc-shaped blades (or S-shaped blades) for starting and a wind turbine (e.g., a Darrieus wind turbine, especially a φ-type Darrieus wind turbine) for high-speed rotation. The number of blades of the wind turbine (which are the main blades of the wind turbine, and can be Darrieus wind turbine blades or other suitable forms of vertical wind turbine blades) is 4, and they are distributed at equal angles (or equal angular distances) (that is, adjacent blades are 90° apart). The wind duct is located inside the wind turbine and forms an integrated wind power rotation system with the wind turbine. There are one or more wind ducts, and multiple wind ducts are distributed vertically in sequence.

[0008] The air duct can be fixedly installed on the fan shaft (or the main body of the fan shaft). Multiple air ducts can be fixedly connected to form an integrated air duct group, or they can be not directly connected to each other.

[0009] Preferably, the vertical span (or longitudinal span, which refers to the dimension in the direction of the wind turbine shaft extension, also known as the height of the entire Savonius duct, or simply the height of the entire duct) of all the wind ducts (one or more of the wind ducts) is consistent with (or matched, or adapted, or equal to) the vertical span of the middle part of the inner space of the wind turbine, except for the part occupied by other parts / structures, and including gaps that do not have a substantial negative impact, such as assembly gaps that should be allowed in practice.

[0010] Preferably, the blades of the wind turbine (the main body of the blades) adopt a symmetrical airfoil, that is, the shape of its cross-section (the section perpendicular to the extension direction of the blade) is the same as or similar to the cross-sectional shape of the symmetrical airfoil; or, the blades of the wind turbine adopt a concave-convex airfoil, that is, the shape of its cross-section is the same as or similar to the cross-sectional shape of the concave-convex airfoil, with the convex surface facing outward.

[0011] Preferably, the blades of the wind turbine are configured with zero lift at both lateral positions (the two ends of the blade sweep surface perpendicular to the vertical axis and in the direction of the external airflow).

[0012] Preferably, the radius of the wind tunnel (the radius of the swept surface of the wind tunnel blades) is one-seventh to one-fifth (including the values ​​at both ends) of the radius of the wind turbine (the radius of the maximum horizontal cross section of the swept surface of the wind turbine blades).

[0013] Preferably, there are three ventilation ducts, all of which are identical and are distributed alternately at 120° intervals in the circumferential direction (the angular distance / rotation difference between adjacent ventilation ducts in the circumferential direction is 120°).

[0014] Preferably, the blades of the wind turbine are provided with horizontal connecting sections at both the upper and lower ends, and the horizontal connecting sections are smoothly connected to the main body.

[0015] Preferably, the upper end of the blades of the wind turbine is connected to the wind turbine shaft in a floating and rotatable manner.

[0016] Furthermore, the wind turbine shaft adopts a longitudinal fixed axis (usually vertical in use), and a floating shaft is provided on the longitudinal fixed axis that is vertically slidably connected to the longitudinal fixed axis. The upper end of the wind turbine blades is rotatably connected to the floating shaft, thereby realizing the floating and rotatable connection between the wind turbine blades and the wind turbine shaft.

[0017] A vertical wind power generation system is provided with a wind turbine and a generator driven by the wind turbine. The wind turbine adopts any of the vertical wind turbine systems disclosed in this invention.

[0018] Preferably, the generator is an external rotor generator, and the wind turbine shaft (longitudinal fixed shaft) is coaxially connected to the generator stator shaft (the axes are on the same straight line) (including adopting an integrated structure). The lower end of the wind turbine blades and the wind tunnel are both fixedly connected to the external rotor of the generator.

[0019] The combination of the wind turbine and the engine can be fixedly mounted on a column or any other suitable mounting base. When mounted on a column, the column and the axis of the wind turbine shaft are preferably on the same vertical straight line.

[0020] The beneficial effects of this invention are as follows: Since the wind turbine is equipped with four equally spaced blades, when one blade is on the windward side (or front, the frontmost point of the blade's sweeping surface in the windward direction), the opposite blade (located on the same diameter) is on the leeward side (or rear, the rearmost point of the blade's sweeping surface in the windward direction). That is, the stress state of the entire wind turbine when any blade is on the windward side is the same as when that blade is on the leeward side (assuming that rotational speed and wind force remain constant). Therefore, although the stress state of the blades on the windward side differs from that on the leeward side due to interference from the wind tunnel, the overall stress state of the wind turbine remains unchanged in both states, and the stress on the wind turbine does not change due to variations in the wind turbine's stress state. This design avoids generating additional vibration and noise, and does not cause fluctuations in wind turbine and generator output due to changes in the stress on the wind turbine rotor. Since the height (vertical span) of the wind tunnel assembly is consistent (or essentially consistent) with the height (vertical span) of the wind turbine rotor, the blocking effect on horizontal winds is essentially the same at different heights. This helps to reduce or avoid vertical (facade) turbulence caused by blocking horizontal winds only in the middle or lower part (vertical middle or lower), improving the stress condition of the wind turbine rotor blades on the leeward side (and nearby), and thus increasing the positive torque. Furthermore, by appropriately increasing the number and density of the wind turbine rotor blades, and through reasonable dimensional matching with the wind tunnel, the wind energy utilization coefficient of the wind turbine generator is effectively improved, increasing the power generation capacity. Based on comparative experiments in multiple northern regions, under the condition that other conditions / structure remain unchanged, this invention, compared to a wind turbine generator with 3 blades and 2 wind tunnels (single wind tunnels), increases daily power generation capacity by approximately 20% under reasonable control. Attached Figure Description

[0021] Figure 1 This is a top view schematic diagram of a wind turbine according to the present invention;

[0022] Figure 2 This is a schematic diagram (front view) of a wind power generation system according to the present invention;

[0023] Figure 3 This is a schematic diagram (front view) of a wind power generation system according to the present invention. Detailed Implementation

[0024] See Figures 1-3In this invention, both the wind turbine (or wind power unit) and the wind generator are vertically mounted. The wind turbine shaft 1 is a vertical shaft (also called a longitudinal shaft, typically vertical in operation). The shaft is equipped with φ-type Darrieus rotor (or other suitable rotor types, hereinafter the same) blades (can be called rotor blades) 3 and a Savonius rotor (or other suitable type of wind turbine capable of low-wind-speed start-up, hereinafter the same) 4. It can be considered a wind turbine composed of a Darrieus rotor and a Savonius rotor. The Savonius rotor can be any suitable existing technology, selected based on the starting wind force / speed and the requirements for size matching and coordinated operation with the Darrieus rotor. The Savonius rotor is positioned within the area (sweeped surface) enclosed by the Darrieus rotor blades. The two rotors are fixedly connected and rotate together. They can be directly fixed at a certain location, fixedly connected via a connector, or fixedly connected to other components to achieve relative fixation, ensuring that they do not interfere with each other. Depending on their kinematic relationship with the turbine shaft, the two impellers (Savonius impeller and Darrieus impeller) can be rotatably connected to the turbine shaft (e.g., via bearings) to allow the two impellers to rotate relative to the turbine shaft; the two impellers can also be fixedly connected to the turbine shaft to drive the turbine shaft to rotate together.

[0025] The Savonius duct can be a single unit, whose height (vertical dimension) should meet the requirements for the total height of all Savonius ducts (vertical span of all Savonius ducts). Alternatively, multiple Savonius ducts can be connected vertically to form a single unit, referred to as a Savonius duct assembly (or Savonius impeller assembly), whose total height (vertical dimension) should also meet the requirements for the total height of all Savonius ducts.

[0026] As a preferred implementation, there are three Savonius ducts, which are distributed alternately at 120° in the circumferential direction. That is, the angular distance / rotation difference between adjacent Savonius ducts in the circumferential direction is 120°, so as to reduce the fluctuation of the overall force during rotation, improve the operational stability, and avoid the structure being too complex.

[0027] As a preferred embodiment, the total height of the Savonius duct should match / adapt to the vertical span of the middle of the inner space of the Darrieus rotor (the height of the inner space of the Darrieus rotor's swept surface in the middle region), so that the Savonius rotor (or rotor assembly) can effectively block the entire area near the inner axis (or turbine shaft) of the Darrieus rotor vertically (excluding areas occupied by other objects). Due to the complete vertical obstruction by the Savonius duct, for horizontal winds, the force conditions (airflow direction, velocity, and pressure) of the main body of the blades on the leeward side of the Darrieus rotor are approximately the same at different vertical positions, effectively reducing the differences in force conditions at different vertical positions. In particular, it effectively reduces the vertical turbulence (vertical component of turbulence) caused by the placement of the Savonius duct in the area where the rotor blades are located on the leeward side. This not only helps to reduce energy loss and increase the lift and positive torque of the rotor blades rotating to the leeward side (and nearby areas), but also facilitates the optimized design and manufacturing of the rotor blades.

[0028] The total height of the Savonius duct can be determined based on the spatial height between the upper and lower ends (and adjacent parts, where appropriate) of the blades (or impeller blades) without any other solid components / structures. In practice, a certain assembly gap or other gap that does not have a substantial negative impact can be left based on processing and assembly conditions. Generally, the Savonius duct should not contact the main body of the blades unless contact is determined at certain points for a specific purpose. For example, the upper and lower ends of the blades should contact / connect with the Savonius duct according to the connection method, or, as in some earlier prior art, a connecting rod is provided for connecting / tying the middle of the blades. In a preferred embodiment of the invention, some deformation of the blades during operation is allowed (mainly deformation under centrifugal force). In this case, a certain distance / gap should be left to ensure that the blades (main body) do not contact the Savonius duct after deformation during operation, avoiding obstruction to the blades due to mutual contact.

[0029] Wind turbine blades can employ any suitable existing technology. A convenient preferred embodiment is that the blade (the main body of the blade) adopts a symmetrical airfoil, that is, its cross-sectional shape (the cross-section perpendicular to the blade's extension direction) is the same as or similar to the cross-sectional shape of a symmetrical airfoil. When the wind (or airflow) is undisturbed (or when the disturbance of the wind to the wind by the Savonius duct and other structures is not considered), the lift or positive torque of such blades is the same on the windward and leeward sides, which facilitates optimization analysis and design, and under normal circumstances, satisfactory output can be obtained.

[0030] Another preferred embodiment is that the blades adopt a concave-convex airfoil design, that is, their cross-sectional shape is the same as or similar to that of a concave-convex airfoil, with the convex surface facing outwards. This type of blade is advantageous for obtaining greater lift / torque, especially since the Darrieus rotor incorporates a Savonius duct, which blocks the straight path / channel between the windward and leeward sides. This makes the airflow field on the leeward side significantly different from that on the windward side. Experiments have shown that under common wind conditions, this concave-convex airfoil blade has greater output and more stable operation.

[0031] As a preferred embodiment, the blades of the concave-convex airfoil are preferably configured such that the lift is zero at the lateral positions. The angle between the chord line of the symmetric airfoil and the radial direction (radius, or the radius of the swept surface in the horizontal direction) of the Darrieus rotor at the corresponding position is determined experimentally and is usually not 90°. In contrast, the angle between the chord line of the symmetrical airfoil blade and the radial direction of the Darrieus rotor at the corresponding position is typically 90°.

[0032] Due to the obstruction / interference of airflow by the Savonius duct, a suitable size ratio between the Savonius duct and the Darrieus rotor is necessary. This ensures that the airflow pushing or bypassing the Savonius duct has an optimized effect on the blades located on the leeward side, resulting in higher torque, higher operational stability, and better start-up performance. Based on experiments, a suitable size ratio that balances these requirements is between one-seventh and one-fifth of the radius of the Savonius rotor.

[0033] Both the upper and lower ends of the wind turbine blade are provided with horizontal connecting sections 4. The horizontal connecting sections of the blade are smoothly transitioned to the main body of the blade. The blade is connected to the wind turbine shaft through the upper and lower horizontal connecting sections (including direct connection and indirect connection through other parts). This blade structure and corresponding connection method can significantly reduce or avoid stress concentration at the connection point and prevent the phenomenon of connection point breakage that is prone to occur at high speed.

[0034] The connection between the upper end of the wind turbine blade and the wind turbine shaft can be any suitable method, such as a rotary connection that does not allow vertical movement (relative movement) (e.g., a bearing connection). A preferred embodiment is that the upper end of the blade is connected to the wind turbine shaft in a floating rotary connection. This allows the blade to have different deformation amounts at different speeds by floating the connection part up and down, thus avoiding damage to the blade and its connection structure with the wind turbine shaft due to deformation stress.

[0035] A preferred floating connection method is that the fan shaft adopts a longitudinal fixed shaft, and a floating shaft is provided on the longitudinal fixed shaft and is vertically slidably connected to the longitudinal fixed shaft. The floating shaft can be a sliding sleeve fitted on the longitudinal fixed shaft or a sliding shaft inserted into the longitudinal fixed shaft. It can slide up and down relative to the fan shaft and cannot wobble / sway. The upper end of the blade is rotatably connected to the floating shaft (for example, through a bearing), thereby realizing the floating and rotatable connection between the blade and the fan shaft.

[0036] A spline fit, especially a long spline fit, can be used between the floating shaft and the longitudinal fixed shaft.

[0037] The wind turbine of the present invention can be used in a wind power generation system, whereby the input shaft of the generator 5 is fixedly connected to the wind turbine shaft or connected through a transmission mechanism, and the wind turbine drives the generator to rotate and generate electricity.

[0038] The generator is preferably installed vertically, with the input shaft facing upwards. This results in a vertical wind power generation system where both the wind turbine and the generator are installed vertically.

[0039] In a preferred embodiment, the generator is an external rotor generator. In this case, the lower end of the blades and the lower end of the Savonius wind tunnel can be fixedly connected to the external rotor of the generator to drive the external rotor to rotate. The wind turbine shaft is set as a fixed shaft, and the lower end of the wind turbine shaft (e.g., the lower end of the longitudinal fixed shaft) is connected to the stator shaft of the generator coaxially (the axes are on the same straight line) to form an integral fixed shaft.

[0040] The wind turbine and generator constitute the main body (working part, or working section) of the wind turbine generator system. The combination of the wind turbine and generator can be mounted on a column, or installed on a platform-type mounting base on the roof, or on a ground-based three-dimensional support. For example, a box 6 with a frame can be used as a ground-based three-dimensional support. The box has a door 7, and the wind turbine and generator combination is installed on the top of the box. The box contains an energy storage device and corresponding control circuits and / or controllers, thereby forming a power unit based on wind power generation.

[0041] Unless otherwise specified, the preferred and optional technical means disclosed in this invention can be arbitrarily combined to form several different specific embodiments when one preferred or optional technical means is a further limitation of another technical means.

Claims

1. A vertical wind turbine system, comprising a longitudinal fan shaft, on which are mounted a fan duct composed of arc-shaped blades for starting and a fan wheel for high-speed rotation, the fan duct being located inside the fan wheel and forming an integrated wind power rotation system with the fan wheel, characterized in that... The wind turbine blades have horizontal connecting sections at both the upper and lower ends, which smoothly transition into the main body. The turbine shaft is a longitudinal fixed axis, on which a floating shaft is vertically slidably connected. The upper end of the wind turbine blades is rotatably connected to the floating shaft, thus achieving a floating and rotating connection between the wind turbine blades and the turbine shaft. The up-and-down movement of the connection allows the blades to deform at different speeds, preventing damage to the blades and their connection structure due to deformation stress. The wind turbine has four blades, evenly spaced. When any blade is on the windward side, the entire... The stress condition of each wind turbine is consistent with the stress condition of the entire wind turbine when the blade is on the leeward side, to avoid fluctuations in generator output. The wind turbine blades are designed with zero lift on both sides in the lateral direction. The vertical span of all wind ducts is consistent with the vertical span of the middle of the inner space of the wind turbine, in order to reduce the difference in stress conditions at different positions in the vertical direction and reduce the vertical turbulence caused by the wind ducts in the area where the wind turbine blades are located on the leeward side. There are three wind ducts, all of which are the same and are distributed vertically and vertically, alternating at 120° intervals in the circumference, to reduce the fluctuation of the overall stress during rotation.

2. The vertical fan motor system as described in claim 1, characterized in that... The radius of the wind tunnel is one-seventh to one-fifth of the radius of the wind turbine.

3. A vertical wind power generation system, comprising a wind-driven mechanism and a generator driven by the wind-driven mechanism, characterized in that... The pneumatic mechanism adopts the vertical pneumatic motor system as described in any one of claims 1-2.

4. The vertical wind power generation system as described in claim 3, characterized in that... The generator is an external rotor generator. The wind turbine shaft is coaxially connected to the generator stator shaft. The lower ends of the wind turbine blades and the wind turbine assembly are fixedly connected to the external rotor of the generator.

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