Hybrid vertical-axis wind turbine

Abstract

The present invention relates to a hybrid vertical-axis wind turbine comprising an outer Darrieus rotor (10) and an inner Savonius rotor (20), wherein the Darrieus rotor (10) comprises a plurality of Darrieus blades (11) and the Savonius rotor (20) comprises a plurality of Savonius blades (21).

Description

HYBRID VERTICAL AXIS WIND TURBINE SCOPE

[0001] The present invention pertains to the generation of electrical energy from wind power. In particular, it relates to vertical-axis hybrid wind turbine technologies and their rotors. BACKGROUND

[0002] Currently, various stakeholders face limitations in their economic capabilities due to the lack of broader solutions for electricity generation. While wind energy sources are available, they lack the characteristics offered by traditional technologies. This is due to the difficulties in operating efficiently in turbulent conditions, with winds changing direction and average speed in a matter of seconds.

[0003] The concept of "plant factor" in electricity generation projects is key to determining their technical and economic viability. However, today in Chile and around the world, a market trend is focusing on finding electricity generation projects during "non-solar hours," further emphasizing the production advantages of wind power projects. This is due to the broad availability of this energy source and its ability to provide power during these time zones. This entire scenario is driven by three main reasons: increased energy consumption, the need to decarbonize the energy mix, and the need to avoid overloading the electrical grid by ensuring that investments in distribution systems are viable and phased in over time.

[0004] Currently, the industry cannot reduce the minimum viable spaces of a horizontal axis wind turbine project; however, the vertical axis turbine can reach 50% less surface area than that of a horizontal axis turbine, due to the large "wake effect" that negatively impacts the performance of the other turbines in the park.

[0005] Finally, there are problems related to the impact of these wind projects on communities, due to noise pollution (dB) and vibrations.

[0006] Currently, conventional horizontal-axis wind turbines are not capable of operating efficiently in low wind speeds (below 5.8 m / s) and generating electricity. On the other hand, Savonius-type wind turbines are capable of operating in low winds, but their efficiency rapidly decreases as wind speed increases. In turn, the Darrieus turbines are capable of operating efficiently within an intermediate range. For these reasons, efforts have been made to incorporate the advantages of both turbines, thus creating a hybrid Darrieus-Savonius turbine, a concept that has gained traction in recent years. However, the implementation of these technologies in the field of electricity generation has faced challenges that hinder their development, as they exhibit inefficient and fluctuating operating curves that directly affect the coupling of an electric generator.

[0007] US201 1025071 A1 describes a hybrid-type vertical-axis wind turbine for wind power generating devices, comprising a support structure that concentrically supports a set of internal Savonius blades and a set of external Darrieus blades, wherein the turbine shaft has a lower end that can be connected to an electric generator to transform the kinetic energy of the wind into electrical energy, characterized in that said Darrieus-type blades of the external rotor and the Savonius-type blades of the internal rotor have—one or the other or both—a twisted development in the axial direction of the hybrid turbine, wherein the value of the twist is between 90° and 0° o .

[0008] Another similar solution is disclosed in document JP2007040276 A, which describes a wind turbine for a Darrieus-Savonius wind power generation device. This device comprises a wind turbine section having Darrieus and Savonius blades mounted on a rotor shaft, and a generator for generating power by rotating the wind turbine section. Torque is generated by a weak wind to rotate the wind turbine. The plurality of gently curved Savonius blades are arranged around the rotor shaft in a well-balanced manner. Savonius plates are arranged at the upper and lower ends of the Savonius blades and fixed to the rotor shaft.The Darrieus vanes are each formed by gently curving a band element that has a constant width and a central cross-section swollen to be thicker, and both ends of these are connected via pins to the front ends of the Darrieus vane locking brackets that face the Savonius plates and extend outwards.

[0009] Document AU2014100506 A4 describes a Savonius wind turbine design combined with a Darrieus wind turbine design. The Savonius turbine section allows the combined turbine system to begin rotating under low wind conditions, enabling the Darrieus turbine section to start rotating at a much lower wind speed compared to if the Darrieus section were separate from the Savonius section. This is because the Darrieus turbine design typically requires a Higher wind speeds are required to begin rotating. Increased power generation is achieved by incorporating a magnetically levitated axial flux AC motor (as part of the wind turbine unit design).

[0010] On the other hand, document CN106032787 A describes a combined wind wheel for a vertical-axis wind turbine, combining a Savonius-type wind wheel and a Darrieus-type wind wheel, wherein the Savonius-type wind wheel comprises three semicircular arc blades and three blocks. The wind piece and the upper and lower circular plates of the fixed semicircular arc blade and the windscreen are also included. The three semicircular blades are evenly distributed on the circular plate, forming an angle of 120° with each other, and the windscreen is positioned over one semicircular blade. The centerline of the windscreen is perpendicular to the semicircular arc blade. The Darrieus-type wind wheel is a Darrieus cp wind wheel.

[0011] However, the systems described retain the same problems mentioned previously; that is, they have inefficient and oscillatory curves that directly affect the coupling of an electric generator, reducing the efficiency of electricity generation. Furthermore, current systems present significant construction challenges due to labor, time, and long-term fixed costs, making this type of design unprofitable. Therefore, it is necessary to develop new rotor alternatives for wind turbines that improve performance and efficiency, especially at low wind speeds. SUMMARY OF THE INVENTION

[0012] The present invention relates to a vertical-axis hybrid turbine, configured as a Darrieus-Savonius hybrid turbine. This allows the turbine of the invention to operate at low wind speeds, characteristic of a Savonius turbine, and also because its efficiency does not decrease with increasing wind speed, as would occur with a purely Savonius turbine. On the contrary, the power coefficient (PC) of the turbine of the invention continues to increase with increasing speed, due to the correct compensating design provided by the Darrieus-type blades. Thus, the synchronization between both types of turbine is the ideal scenario that expands its application and allows for its use in conjunction with electric generators. Therefore, the turbine of the present invention has individual and integral geometric proportions that maximize efficiency and power coefficient (PC).

[0013] The turbine of the invention has a modular configuration in the assembly of its blades, allowing the viability of projects to be solved in places with high difficulty geographically, since it has been configured with dimensions that allow it to be transported inside containers, which facilitates maritime and land logistics, unlike conventional horizontal axis turbines where the length of the rotor blades means that considerations must be taken into account regarding the width of the roads and the radius of the curves of the access roads to analyze the constructability of these projects.

[0014] Finally, the turbine of the invention has a lower noise impact, between 15% and 20% less compared to conventional horizontal-axis turbines of the same size. This advantage allows for an expansion of the area considered "viable" for installing turbines at a site studied for the operation of a wind farm.

[0015] Thus, the technical problem addressed by the hybrid vertical-axis wind turbine is to improve performance in terms of Cp (power coefficient) for electricity generation. This includes improving efficiency at low speeds compared to Savonius rotors alone, where drag is more significant, and then improving input efficiency compared to a Darrieus turbine, since the latter achieves its inertial output at higher wind speeds.

[0016] The turbine of this invention seeks to successfully hybridize both technologies in order to reduce the significant deficits or "deeps" in the turbine's performance curve. This improves the average potential to maximize the performance of both blade types and achieve a wider range of wind speeds where the turbine would operate more efficiently than other hybrid vertical-axis turbines on the market. BRIEF DESCRIPTION OF THE FIGURES

[0017] Figure 1 represents a schematic perspective view of the hybrid turbine, according to one embodiment of the invention.

[0018] Figure 2 represents a schematic elevation view of the turbine of the invention at an installed site, according to one embodiment thereof.

[0019] Figure 3 represents a schematic plan view of a cross-section of the turbine rotor showing the phase angle for coupling between the Savonius rotor and the Darrieus rotor.

[0020] Figure 4 represents a schematic front view of one embodiment of the invention where the difference in proportions for each rotor can be seen.

[0021] Figure 5 is a plan view of the Darrieus turbine profile showing the twist angle of the Darrieus blade profile and its outer profile chord.

[0022] Figure 6 illustrates a plan view of the Darrieus turbine where the twist angle of the Savonius blade and its inner profile chord can be observed.

[0023] Figure 7 illustrates a graph of power coefficient (Cp) vs wind speed in m / s for three types of vertical helical turbines.

[0024] Figure 8 illustrates a graph of power coefficient vs wind speed in the low speed range for three types of vertical helical turbines.

[0025] Figure 9 shows a graph of torque vs wind speed for four types of vertical axis turbines measuring drag force. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention relates to a hybrid vertical-axis turbine with Darrieus blades and Savonius blades.

[0027] The invention consists of a vertical axis wind turbine (100) with a rotor design incorporating two types of rotors: an outer Darrieus rotor (10) and an inner Savonius rotor (20), where both rotors have curves in their flat X and Y cross-sectional profiles. Each rotor has separate operating maxima and minima, and the correct combination of attack and twist angles provides aerodynamic advantages that contribute to improved performance along the operational curve "Hybrid turbine power coefficient (80) and TSR Tip speed ratio: ratio between the speed of the blade tip and the wind speed)," a characteristic and dimensionless graph that differentiates the behavior of the different types of rotor designs.

[0028] The vertical turbine (100) of the invention has several innovative technical features that allow it to address the problems mentioned above. In particular, the Savonius rotor (20) is designed for drag, and the Darrieus rotor (10) is designed for lift. Both rotors (10, 20) are coupled to each other and rotate around a common mast (30). This mast (30) can be anchored to a surface (40).

[0029] In one embodiment of the invention, the Darrieus rotor (10) is of the helical type. Equivalently, in some embodiments of the invention, the Savonius rotor (20) is of the helical type.

[0030] The Darrieus rotor (10) comprises a plurality of Darrieus blades (11) with at least two Darrieus blades (11). The Savonius rotor (20) comprises a plurality of Savonius blades (21) with at least two Savonius blades (21). The number of Darrieus blades (11) and Savonius blades (21) is a relevant design factor because increasing the number of blades improves the inertial stability of the system. This is because a greater number of force pulses per revolution is generated, resulting in less oscillation of the force experienced by the generator and the structure. Additionally, turbines with a greater number of blades operate at a lower speed than turbines with fewer blades. However, a greater number of blades increases the active volume used by a Savonius rotor (20), which can cause interference with an external Darrieus rotor (10).

[0031] In some embodiments of the technology, the number of Darrieus blades (11) of the Darrieus rotor (10) is equal to the number of Savonius blades (21) of the Savonius rotor (20). In the invention, the number of blades on each rotor varies between two and five blades, preferably between three and five blades.

[0032] The invention presents an airfoil for the Darrieus blades (11) of the Darrieus rotor (10), which is fitted and compatible with the inner Savonius rotor (20) so that the aerodynamic phenomena inherent in the outer Darrieus rotor (10) do not adversely interfere with the operation of the inner Savonius rotor (20). Furthermore, this airfoil for the Darrieus blades (11) must be suitable for hybridization with the inner Savonius rotor (20), ensuring seamless integration between the two systems.

[0033] The Darrieus blade profile (1 1 ) is described from four-digit NACA profiles, where the first digit describes the maximum bow or curvature as a percentage of the chord in asymmetric profiles, the second digit describes the distance of the maximum bow from the leading edge of the airfoil in tenths of the chord, and the last two digits describe the maximum thickness of the airfoil as a percentage of the chord.The Darrieus blade profiles (11) are preferably found among the symmetrical profile groups, where, after several tests, they were able to outperform the asymmetrical profiles in terms of hybrid rotor start-up speed, turbulence generated towards the Savonius rotor, and overall rotor stability and vibrations. The NACA 00XX profile group, which this hybridization aims to protect, ranges from a NACA 0008 profile to a NACA 0026 profile, with profiles closer to the NACA 0022 profile exhibiting the best performance in the analyses performed. (Table 1: Performance of Model 0022 according to % of the wind tunnel frequency range).

[0034] Table 1 shows the experimental results obtained for the phase angle between the tip of the Savonius blade and the tip of the nearest Darrieus blade with a NACA 0022 airfoil. Different models and phase angles were tested to determine the take-off speed (the wind speed at which the rotor left inertia) and the stall speed (the wind speed at which the rotor came to a complete stop) in a small-scale wind tunnel. Due to the scale of this test, both the take-off speed and the stall speed are relatively high compared to the speeds calculated in other tests and simulations. This is explained by the small size of the wind tunnel and the scale of the model, which amplify the aerodynamic phenomena of wake, boundary layer, and turbulence.Additionally, the mounting hardware for these models was oversized for safety reasons during testing, and measuring instruments were positioned upstream of the test areas, increasing aerodynamic disturbances. However, this analysis revealed that the phase angle with the best results is between 20° and -20°. Table 1: Starting and stopping speeds for different phase angles with a symmetrical NACA 0022 airfoil.

[0035] Each blade type defines a profile, where each profile has a twist angle. This angle corresponds to the relative angle between the profiles and the horizontal. This parameter is related to the profile's efficiency, improves the gradual approach to the blade surface, and increases the contact time with the air mass, factors that help improve the distribution of torque forces generated in the turbine (100), thus improving its operation before a decrease in efficiency. Therefore, it is vital to define an optimal range for the twist angle (12, 22) to maximize turbine efficiency. According to the invention, both Darrieus blades (11) and Savonius blades (21) They possess a twist angle (12, 22) ranging from 20° to 50°, preferably between 28° and 43°. In some embodiments of the invention, the Darrieus blades (1 1 ) and the Savonius blades (21 ) have the same twist angle (12, 22) in both rotors (10, 20).

[0036] According to the invention, the turbine dimensions (100) depend on the ratio between the diameter (D) and height (H) of the turbine rotor (100). This ratio varies between 3:4 and 4:7. The diameter-to-height ratio is crucial for optimizing the structural and mechanical efficiency of the Darrieus blades. This ratio significantly reduces the bending induced at the blade tips by centrifugal forces generated during turbine rotation. These bending effects were studied to optimize weight, size, and internal reinforcements. The 5:7 ratio yields the best results, falling within acceptable ranges for the materials used in this design, thus extending service life and improving technical and economic performance.

[0037] Additionally, the geometric relationship between the rotor diameter (15) and the rotor height (71) directly impacts the distribution of torsional loads on the blades. Blade torsion is optimized so that the twist angle is uniformly distributed along their length, minimizing stress concentration points that could lead to fatigue failures. This is relevant for the design of beam-blade coupling points; the proposed configuration allows for precise synchronization between torsion and forces perpendicular to the connection points, reducing the required space for these joints and improving the overall structural integrity of the system.

[0038] The Savonius blades (21) define an inner airfoil chord (23), and the Darrieus blades (11) define an outer airfoil chord (13). In one embodiment of the invention, the ratio between the inner and outer airfoil chords is ideally 3:4. Variation is possible, as it depends on other airfoil interference factors, such as the distance or spacing between the rotors, which precisely determines the chord ratios. The acceptable range for improving the performance of this hybrid turbine is from 3:8 to 7:8. It is important to remember that the Savonius airfoil chord is shorter than the Darrieus airfoil chord. This is because the drag force of the Savonius airfoil is only efficient in low winds (below 5.8 m / s), while the Darrieus rotor plays a more significant role in this hybrid design, as its efficiency is considerable even in medium and high winds.(Average winds range from 5.8 to 11.1 m / s and high-altitude winds range from 11.2 to 20 m / s).

[0039] The height of the coupling point (71) of the turbine (100), with the static support, is preferably determined relative to the height of the Darrieus rotor (10), with a ratio ranging from 1:4 to 1:2. This allows for a more stable design with respect to the distribution of centrifugal and torsional forces present during operation (turbine rotation). Furthermore, these ratios reduce the leverage effect, as this coupling point is often closer to the turbine's center of mass, thus reducing stresses at this point.

[0040] In one embodiment of the invention, the number of Darrieus blades (11) of the Darrieus rotor (10) is equal to the number of Savonius blades (21) of the Savonius rotor (20). The coupling between the Darrieus rotor (10) and the Savonius rotor (20), when they have the same number of blades, is such that their respective blades are offset from each other. Thus, the coupling between the Darrieus rotor (10) and the Savonius rotor (20) has a phase angle (50) between the tip of the Savonius blade and the tip of the nearest Darrieus blade, which is in the range of -20° to 20°, as shown in Figure 3. The main reason for this angular phase shift configuration is that it allows both types of blades to achieve more efficient interaction with the wind flow, given that both types of rotors capture the wind differently.The Savonius rotor makes better use of low wind speeds, while the Darrieus rotor benefits from higher speeds. This angular offset of the blades significantly reduces direct interference between the two rotor types. Another technical factor to consider with this angular offset is the reduction of internal turbulence that both rotors can generate, improving the overall efficiency of the system. This offset ensures that there is always a pair of blades at a favorable angle, which normalizes torque fluctuations and reduces mechanical vibrations.

[0041] Figure 1 shows a front view of a vertical axis turbine rotor (100) of the Hybrid Thpala Helical type, where in addition to the Savonius (20) and Darrieus (10) type rotors, the axial flow generator (60), the beams, the column and other joining elements that are part of the optimized design are also observed, where each piece met the necessary specifications to stand out individually and integrally, through multiple static and dynamic resistance simulations.

[0042] Figure 2 shows a front view of the Hybrid rotor mounted on its supporting structure consisting of its coupling point (70), mast (30), and the mast anchoring surface (80) or foundation. This provides a better understanding of the actual space occupied by this type of wind turbine, which provides the minimum required stability, ranging from the operational and rotational demands of the vertical axis turbine (100) to conditions in a braking state, being able to withstand wind speeds of up to 32 m / s.

[0043] Figure 3 shows a plan view that emphasizes only the Darrieus (11) and Savonius (21) blades, along with the most relevant angles that define the hybrid design. This is because the wind flow that first impacts the Darrieus blades (12) directly affects the airflow received by the Savonius rotor (21), and in turn, the type of wind that the Darrieus blades (11) receive downstream is partially affected by the Savonius blades (21). Therefore, the twist angles of both blades (12, 22) and the phase shift must allow synergy between them, complementing each other for as long as possible, without hindering the Cp of the hybrid turbine (80), throughout the entire operational and post-operational range (turbine in a static state).

[0044] Figure 4 shows a front view that emphasizes only the Savonius blades (21) and Darrieus blades (11), differentiating the swept areas (14,15,24,25) and the height at which one rotor interferes with the other. Since this turbine is a vertical axis turbine (100), it has variables that, although they increase efficiency in certain ranges, there are other ranges in which it becomes dangerous and unstable (wind speeds (over 13 m / s)). Therefore, the study of this proportion focused on designs that promoted stability, considering only 1 coupling point (70) in the lower area of ​​the vertical axis turbine (100).

[0045] Figure 5 shows a plan view of the Darrieus blade (11), whose geometry maximizes lift. The twist angle (12) allows the Darrieus blades (11) to generate the necessary lift without hindering the performance of the Savonius rotor (20) during takeoff (inertial release). The chord of the Darrieus airfoil (13), which defines the leading and trailing edges of the symmetrical airfoil of the Darrieus blade (11), influences the captured airflow and its aerodynamic efficiency.

[0046] Figure 6 shows a plan view of the Savonius blades (21) arranged equidistantly within the Savonius rotor (20), which has been optimized for capturing low and medium-speed winds. The twist angle (22) of the Savonius blade (21) and the chord (23) allow for airfoils that align with the position of the Darrieus blades (11), as these have been shown to maximize aerodynamic efficiency and minimize vibrations, thus increasing the system's lifespan.

[0047] Figure 7 shows a graph of Cp versus wind speed in meters per second, which demonstrates the projected performance curve of the turbine blades. helical turbines of Savonius, Darrieus and Hybrid types, Cp hybrid turbine (80) have a dotted line.

[0048] Figure 8 shows a detailed view of Figure 7, in the range of greatest influence of hybridization given the Cp of the hybrid turbine (80) with respect to the separate vertical axis helical rotors.

[0049] Figure 9 shows a comparison of drag forces for different types of wind turbines. The hybrid three-bladed helical turbine stands out as the most efficient option, as the system makes better use of the wind to generate energy at higher speeds.

[0050] In one embodiment, the present technology relates to a vertical-axis hybrid turbine comprising an outer Darrieus rotor (10) and an inner Savonius rotor (20), with a plurality of Darrieus blades (11) and a plurality of Savonius blades (21), wherein the Darrieus blades (11) are helical with a twist angle between 35° and 50°; and wherein the ratio between a turbine diameter (D) and the turbine height (H) is between 3:4 and 5:7.

[0051] In another embodiment of this technology, the Savonius blades (21) are helical, with a twist angle (22) between 35° and 50°. This configuration of the Savonius blade, with a twist angle between 35° and 50°, optimizes wind capture at low speeds (between 2.5 and 4 m / s), improving the stability of the turbine and the system. The blade design, combined with its twist, reduces vibrations and improves load distribution, resulting in a more uniform distribution throughout the system. This improvement extends the system's lifespan and increases its performance.

[0052] In another embodiment of this technology, the twist angle of the Darrieus (12) and Savonius blades is between 40° and 43°. This twist angle optimizes airflow interaction along the system's blades, reducing energy losses caused by turbulence and increasing the power coefficient (80)(81) at different TSRs. Structurally, the hybridization of both rotors, shown in Figure 1, minimizes vibrations and improves load distribution. This directly contributes to improved durability and performance in the medium and long term. The twist angle focuses on maximizing efficiency when operating at wind speeds of 3–17 m / s and offers more stable and predictable performance in response to changes in wind direction.

[0053] The blade configuration of 3 to 5 blades on each rotor of the vertical-axis hybrid turbine solves the technical problem of efficiency by balancing the Interaction between Savonius and Darrieus rotors. The multiple blades allow for maximizing wind energy utilization under varying conditions, increasing the capture area and improving the transfer of kinetic energy to the rotors. The operational stability inherent in this design reduces the risk of excessive vibrations or imbalances.

[0054] With a larger blade capacity, the response to variations in wind speed is improved, which contributes to a higher power coefficient of the hybrid turbine (80) and efficiency in the complete system.

[0055] In another embodiment of this technology, the Darrieus blades (1 1) have an airfoil profile between a NACA 0008 and a NACA 0026, which improves turbine efficiency by increasing lift and minimizing drag. This enhances system balance through structural stability and aerodynamic performance at varying wind speeds. The thinner NACA 0008 airfoil reduces drag, which is particularly effective in strong winds, while the thicker NACA 0026 airfoil improves lift in weaker winds.

[0056] These ranges of variation in the Darrieus blade profile, in hybridization with the Savonius blades that facilitate drag, allow the turbine to operate more efficiently with winds around [3-17 m / s], improving the TSR ratio and power coefficient of the hybrid turbine (80)

[0057] In another implementation of this technology, the number of Darrieus blades (11) is equal to the number of Savonius blades (21). This improves the aerodynamic and mechanical balance of the system. This equal number of blades results in a uniform distribution of forces along the shaft, minimizing vibrations and mechanical wear, which directly contributes to the turbine's lifespan. The configuration optimizes energy transfer between both types of blades, resulting in a more continuous and uniform airflow.

[0058] This rotor balance enhances the stability of our turbine, its efficiency, and contributes to a greater potential for generating energy with variable and turbulent winds.

[0059] In another embodiment of this technology, the Darrieus blades (11) and the Savonius blades (21) are offset from each other by an angle between -20° and 20°, measured on a plane at the heights shared by both rotors. This configuration contributes to improved efficiency by reducing negative interference between the airflows circulating in both types of rotors. This adjustment allows both blades to optimally capture wind, stabilizing the flow and reducing internal turbulence, resulting in improved system performance.

[0060] This precise blade synchronization with a phase shift allows the turbine to maximize energy conversion efficiency, especially in winds between 2.5 and 4 m / s. Furthermore, this design reduces torsional forces and vibrations throughout the system.

[0061] In another embodiment of this technology, the Savonius blades (21) define an inner chord and the Darrieus blades (11) define an outer chord, with the inner-to-outer chord ratio being 3:4. The blade chord ratio in the vertical-axis wind turbine combines the advantages of the drag-operated Savonius rotor and the lift-operated Darrieus rotor. Operating this hybrid configuration with its respective optimal angles of attack and twist allows for improved aerodynamic performance, increasing efficiency across a wide speed range. Configuring a Savonius-to-Darrieus airfoil chord ratio of 3:4 optimizes airflow between the rotors, maximizing energy transfer and overall system performance. This improved airflow interaction between the two blade configurations maximizes the energy efficiency and power coefficient of the hybrid turbine (80).

[0062] In another embodiment of this technology, the swept area, or cross-sectional area, of the Savonius turbine rotor and the cross-sectional area of ​​the Darrieus turbine rotor are in a ratio between 1:25 and 3:25. In the iterations performed, the aero-structural behavior of a hybrid turbine was detrimental when the swept area of ​​the Savonius turbine exceeded 3:25 at speeds above 14 m / s. Conversely, the swept area of ​​the Savonius turbine was negligible in terms of output benefits when this ratio was less than 1:25.

[0063] This characterization of the rotor areas offers several important technical advantages that improve the overall system efficiency. The Savonius rotor, being smaller and possessing drag characteristics, allows for improved start-up at wind speeds between 2.5 and 4 m / s. The Darrieus rotor (10), with a larger drag area of ​​1:25 to 3:25 compared to the Savonius, maximizes the capacity to capture wind energy more stably at higher speeds (without Cp losses). This hybridization, with its different operating principles and sizes, enhances stability and reduces vibrations, especially in turbulent wind conditions. The power curve covers a wider range, resulting in a greater operating range and improved TSR and power coefficient of the hybrid turbine (80). REFERENCE NUMBERS

[0064] Below is a list of the elements of the invention illustrated in the figures and their respective reference numbers. 10 Darrieus Rotor 11 Pala Darrieus 12 Darrieus blade twist angle 13 Darrieus profile chord 14 Darrieus rotor height 15 Darrieus rotor diameter 20 Savonius Rotor 21 Pala Savonius 22 Savonius blade twist angle 23 Savonius profile chord 24 Savonius rotor height 25 Savonius rotor diameter 30 Mast 40 Mast anchoring surface 50 Phase shift angle 60 Electric generator 70 Docking point (to the mast) 71 Docking height (to the mast) 80 Cp hybrid turbine 100 Vertical Shaft Turbine

[0065] Finally, it should be noted that various specific parameters of the invention, such as dimensions, choice of materials, and specific aspects of the preferred configurations described, may vary or be modified according to operational requirements. Therefore, the configurations described above are not intended to be limiting, and these variations and / or modifications are within the spirit and scope of the invention.

Claims

MODIFIED CLAIMS received by the International Bureau on 17 January 2024 (17.01.2024) 1. A hybrid vertical-axis turbine with an outer Darrieus rotor (10) and an inner Savonius rotor (20), comprising: a plurality of Darrieus blades (11) and a plurality of Savonius blades (21), wherein the Darrieus blades (11) are of helical type with a twist angle (12) being between 35° and 50°; wherein a ratio of a diameter (15) of the turbine to a height (14) of the turbine is between 3:4 and 5:7; and wherein a cross-sectional area of ​​the Savonius turbine rotor to a cross-sectional area of ​​the Darrieus turbine rotor is in a ratio between 1:25 and 3:

25.

2. The hybrid turbine according to claim 1, wherein the Savonius blades (21) are of the helical type with a twist angle (22) that is between 25° and 50°.

3. The hybrid turbine according to claim 2, wherein the twist angle (12, 22) of the Darrieus blades (11) and the Savonius blades (21) is between 25° and 43°.

4. The hybrid turbine according to claim 1, wherein the number of Darrieus blades (11) and the number of Savonius blades (21) is between three and five blades per rotor.

5. The hybrid turbine according to claim 1, wherein the Darrieus blades (11) have a symmetrical aerodynamic profile comprised between a NACA 0008 profile and a NACA 0026 profile.

6. The hybrid turbine according to claim 1, wherein the number of Darrieus blades (11) is equal to the number of Savonius blades (21).

7. The hybrid turbine according to claim 5, wherein the Darrieus blades (11) and the Savonius blades (21) are offset from each other by a phase angle (50) between -20° and 20°.

8. The hybrid turbine according to claim 1, wherein the profile of the Savonius blades (21) and the Darrieus blade profile (11) define a chord (23, 13) where the ratio between the chord of the Savonius profile and the chord of the Darrieus profile can range from 3:8 to 7:

8. 16 MODIFIED SHEET (ARTICLE 19)

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