Electromechanical system for wind turbines having a vertical axis of rotation and method for using same

Abstract

The present invention relates to an electromechanical system for wind turbines having a vertical axis of rotation (1) and a method for using same (P1), which incorporates an electronic regulation and control system to carry out its operation at the point of maximum power (Maximum Power Point Tracking, MPPT) and an electronic system for conditioned dumping of the generated electrical energy into an electrical network (On-Grid) (60), which is characterised in that it contains: an electromechanical subsystem for wind turbines having a vertical axis of rotation (10) and an electronic conditioning subsystem (40) for conditioning the electrical energy produced by synchronous machines (15, 16) before being dumped into an electrical network (60) and a plurality of blade tip winglets (100) having a cross section with an aerodynamic profile for low wind speed and high turbulence which cause levitation in the wind rotor (01).

Description

[0001]

[0002] OBJECT AND TECHNICAL FIELD OF THE INVENTION

[0003] The present invention belongs to the field of wind energy conversion systems (WECS) and substantially relates to a system and a method for its implementation in a vertical rotation axis wind turbine that particularly has a wind turbine (WT) formed by a plurality of complex blades, to pursue its operation at its maximum power point (Maximum Power Point Tracking, MPPT) for the case of connection to an electrical grid (On-Grid).

[0004] The invention relates to the technical field of electricity generation using renewable energy sources, and more specifically to small-scale wind power. According to the UNE-61400-2 standard (edition 3), a small-scale wind turbine is considered to have a swept rotor area of ​​less than 200 m. 2 , which represents a power of 65 kW. However, in a more common conception, it is considered to include wind turbines of up to 100 kW, which is the limit established for small power generation using any grid-connected technology, as established in Royal Decree 1699 / 2011 regulating the grid connection of small-scale electricity generation facilities.

[0005] GENERALITIES

[0006] The continued increase in energy consumption in modern society has led to a global need for electricity generation from renewable sources, in order to eliminate the carbon footprint and mitigate the effects of climate change. High-power wind power is one of the renewable energies that has experienced the greatest growth in recent years, due to its technological maturity, low cost, and lack of greenhouse gas emissions [1].

[0007] In Spain, the market potential of small wind turbine technology was defined in the Renewable Energy Plan (PER) 2011-2020 [2], which set a target of 300 MW of installed small wind power generation capacity by 2020 (however, according to [3] as of 2019 the actual small wind power capacity in self-consumption applications was below 0.2 MW). Initially, the different small wind system applications were designed for isolated operation in order to consume 100% of the generated energy, but currently, if there is a nearby electricity grid, distributed generation is usually a better option, since the governments of different countries have also approved legislation to regulate the injection of energy into the electricity distribution grid from renewable energy sources.

[0008] Types of wind turbines used in small-scale wind power

[0009] A wind turbine is a device that captures the kinetic energy contained in a wind flow to convert it into mechanical rotational energy.

[0010] Regarding the aerodynamic principles used to capture the wind's kinetic energy in a wind turbine, we have drag (Savonius type), lift (Darrieus type), and hybrid wind turbines (Savonius-Darrieus type), which, depending on their construction technology, can be classified as vertical-axis wind turbines (VAWT) and horizontal-axis wind turbines (HAWT). As a general rule, horizontal-axis machines are based on lift, while vertical ones are drag-based, or they use both principles in a single rotor.Vertical axis wind turbines (VAWT), (omnidirectional, do not require an orientation system towards the incident wind direction), are generally installed in turbulent environments such as cities, due to their theoretically greater efficiency compared to horizontal axis wind turbines (HAWT), (unidirectional, which require an orientation system towards the incident wind direction, e.g. a weather vane), in these types of regimes, marked by variations in wind direction, which have less negative effects on power generation and fatigue loads, as they do not have to be constantly positioned. They are wind turbines in which the position of the blades and the rotor axis are vertical, perpendicular to the ground and to the wind direction.The blades' movement is caused by either the lift force generated by the wind flow striking the blades or by the drag force, depending on the turbine design. Prototypes have achieved hybrid designs, combining the use of lift and drag simultaneously.

[0011] In this sense, patent document no.: US 2011 / 0280708 Al (Pub. 2011) discloses a wind turbine for use in small power with a vertical axis in which its operation in lift mode (Darrieus type) is recommended and which is characterized in that it comprises a rotating axis around a longitudinal axis and a plurality of rigid blades (three) mechanically coupled to the axis that are rotationally displaced from each other around the axis so that each blade has a propeller shape. While patent no.: US 2020 / 0025169 Al (Pub.2020) describes a rotor for vertical-axis mini-wind applications that claims its hybrid operation in lift and drag mode (Savonius-Darrieus type) and that is configured by a plurality (nine) concave-convex type aerodynamic profiles in the form of vertical helical projections, inclined towards counter-rotation and twisted, decreasing the chord, where both ends end in the form of sharks turned towards the upper surface.

[0012] In general, wind turbines used in small-scale wind power do not have a blade rotation system, so power cannot be controlled by adjusting the pitch angle (0). Types of vertical-axis wind turbines used in small-scale wind power

[0013] A vertical-axis wind turbine is a system that uses a vertical-axis wind turbine consisting of a plurality (e.g., 3-9) of complex blades coupled to an electrical generator through a gearbox stage, in order to convert the rotational mechanical energy transferred from the wind turbine into electrical energy in the generator.

[0014] The generators currently in use are radial flux permanent magnet synchronous generators (PMSGs). This technology allows for a high number of rotor magnetic poles (e.g., 44–110 poles), enabling operation at low angular velocities (e.g., 70–750 rpm). They are also energy efficient.

[0015] The electrical energy produced in the PMSG generator requires electronic regulation and control equipment, as well as conditioning before being fed into an electrical grid [3]. They consist of a wind turbine regulation and control system that is made up of an AC / DC rectification pre-stage (RECTIFIER), an intermediate overvoltage limitation stage (BRAKE CHOPPER) and a DC / DC converter final stage (BOOSTER). In addition, a system that delivers the appropriately conditioned electrical energy to the distribution or transmission grid (On-Grid) is made up of a DC / AC inverter stage (INVERTER). The DC / DC stage is frequently integrated into the DC / AC inverter.

[0016] The regulations governing distributed generation in each country determine the technical requirements that these generating facilities must meet regarding the quality of the energy injected into the grid and their legalization. As an example of an application case in Spain [4], there is Royal Decree 842 / 2002, which approves the Low Voltage Electrotechnical Regulation (REBT), specifically in ITC-BT 40 referring to low voltage generating facilities. Regarding the quality of the electrical energy generated, the UNE-EN 50160 standard stands out, focusing on the characteristics of the voltage supplied by general distribution networks, and the UNE-EN 40438:2015 standard, which more generally addresses the requirements for connecting microgenerators to general low voltage distribution networks. Finally, Royal Decree244 / 2019 regulates the administrative, technical, and economic conditions for self-consumption of electrical energy connected to transmission or distribution networks.

[0017] BACKGROUND OF THE INVENTION. REVIEW OF THE NEAREST PRIOR STATE OF THE ART

[0018] Non-patent literature

[0019] The present invention substantially relates to a system and a method for its implementation in a wind turbine with a vertical rotation axis that particularly has a wind turbine formed by a plurality of complex blades, to pursue its operation at its maximum power point (MPPT) for the case of connection to an electrical network (On-Grid).

[0020] In non-patent literature [3] different electronic regulation and control equipment are known, as well as conditioning before being fed to an electrical grid, which electronically implement maximum power point tracking (MPPT). They are grouped into two large groups: proprietary devices (manufactured by the companies themselves for their small power wind turbines) and general purpose devices (manufactured by third-party electronic equipment companies for generic wind turbines).

[0021] Proprietary devices

[0022] A solution adopted by the company Ennera Energy [5] for the electronic regulation of its small power horizontal axis wind turbine model Windera S (HAWT) is found, which is characterized by a DC / DC converter (BOOSTER) being in charge of tracking the maximum power point (MPPT). Another solution stands out, in this case from the firm Bomay [6] for its exclusive design to work with its small power horizontal axis wind turbine model Bornay Wind+ (HAWT), in which an MPPT regulator tracks the maximum efficiency point.

[0023] General purpose devices

[0024] We found the wind box interface (WBI) equipment that was designed by the company Power-One (later acquired by ABB) [7] and that is intended to work with the Aurora family of photovoltaic inverters (also designed by Power-One) but can be purchased independently for general use (today it is offered on its website, although the company ABB expressly indicates that it does not dedicate resources to its improvement or updating).

[0025] Patent literature

[0026] Maximum Power Point Tracking (MPPT)

[0027] Each wind speed corresponds to a specific generator angular velocity (SGV) that produces the maximum generated power. Therefore, for different angular velocities, the power extracted from the wind is reduced. Operating the wind turbine in variable speed mode can achieve optimal wind energy extraction. For this reason, there are many different MPPT control strategies.

[0028] In the closest state of the art in patent literature we find different types of wind energy conversion systems (WECSs) that pursue their operation at their maximum power point (Maximum Power Point Tracking, MPPT) for the case of connection to an electrical network (On-Grid).

[0029] European patent document ES2537126 (Pri. 2009), discloses a variable speed wind turbine and a method for operating the variable speed wind turbine during a power imbalance event that employs an uninterruptible power supply (UPS) adapted to receive the excess power generated in the event of a wind gust.

[0030] There is also the European invention patent document ES2623631 (Pri. 2010), which claims a method for operating a power dissipation unit in a wind turbine when a predefined power difference threshold is exceeded.

[0031] In this regard, the European invention patent document ES2696303 (Pri. 2014) is known, which recommends a method of controlling a wind turbine that allows detecting situations in which the machine is not working at its maximum performance point.

[0032] Non-patent literature references

[0033] 1. Chapman, A., Mclellan, B., Tezuka, T. (2018). Prioritizing mitigation efforts considering co-benefits, equity and energy justice: Fossil fuel to renewable energy transition pathways. Applied Energy, vol. 219, pp. 187-198. https: / / doi.org / 10.1016Zj.apenergy.2018.03.054

[0034] 2. Renewable Energy Plan 2011-2020 (2011). IDAE. https: / / www.idae.es / tecnologias / energias-renovables / plan-de-energias-renovables- 2011-2020

[0035] 3. Arribas de Paz, Luis M., et al. (2020). Small-capacity wind turbines. CIEMAT. https: / / cpage.mpr.gob.es /

[0036] 4. Arribas de Paz, Luis M., et al. (2020). The small wind turbine market in Spain. CIEMAT. https: / / cpage.mpr.gob.es /

[0037] 5. Installation and Maintenance Manual. Windera S wind turbine. Ennera Energy and Mobility SL Code: I.H4.V10.3003, Version: 07. http: / / winderapowersystems.com /

[0038] 6. Hybridization of photovoltaic and small wind energy in a single SMA inverter. https: / / www.bornay.com / es / noticias / hibridacion-de-fotovoltaica-y-minieolica-en-un-mismo-inversor-sma

[0039] 7. Legacy small wind inverters. ABB website. htt s: / / new.abb.com / ower-converters-inverters / wind-turbines / small-wind / le acy-small-wind-inverters-old

[0040] Technical problem

[0041] The systems known in the prior art have a technical limitation or problem, which is mainly focused on the following aspects:

[0042] X They incorporate control methods that make it possible to detect situations in which the generator is not working at its maximum performance point, so that once these situations are detected, an automatic correction of the control parameters is carried out and return the wind turbine to its optimal operating point. This “error detection-correction” methodology is ineffective for small power and low inertia wind turbines, which are subject to a lot of variability due to the type of gusty and turbulent winds at their locations, e.g.: urban spaces, buildings, etc. Furthermore, in general these methods require wind turbines composed of blades that can modify their pitch angle (!) to carry out said correction.Systems that employ electronic regulation, control, and conditioning equipment to feed generated electrical energy into a proprietary power grid for maximum power point tracking (MPPT) are designed exclusively to operate with their own brand of small wind turbines, and therefore cannot be used with third-party mini wind turbines.

[0043] X Systems that use electronic regulation, control and conditioning equipment to transfer the generated electrical energy to a general-purpose electrical network for maximum power point tracking (MPPT) are not currently marketed or if they are, it is without dedicating resources to their improvement or updating.

[0044] X Systems that employ electronic regulation, control and conditioning equipment to feed the generated electrical energy into an electrical grid using a conventional inverter (with one or more MPPT inputs) used in photovoltaics present inadequate functioning because a wind turbine behaves very differently from a set of solar panels. The response dynamics are very different since solar panels have a much slower response than a wind turbine can have. For this and other reasons, solar inverters should not be used directly from a rectified signal from a wind turbine, since the rapid voltage variations associated with wind behavior cause the inverter to not function properly.

[0045] Technical advantage provided by the invention

[0046] The present invention fully satisfactorily resolves the problem previously described, in each and every one of the different aspects discussed and detailed below:

[0047] The invention does not require a control method for “error detection-correction” of operation at the optimum point, since it recommends a method that uses an electromechanical system to force the specific angular speed of the generator at the point of maximum power for each wind speed, and is therefore preferably applicable to wind turbines composed of fixed blades, that is, blades that cannot modify their pitch angle (%).

[0048] The system proposed by the invention employs electronic regulation, control and conditioning equipment to feed the generated electrical energy into a general-purpose electrical grid for operation at the maximum power point (MPPT) so that it can be used in third-party mini wind turbines. The system proposed by the invention employs electronic regulation, control and conditioning equipment to feed the generated electrical energy into an electrical grid that uses a conventional inverter used in photovoltaics, but without inputs with MPPT function, and therefore operates appropriately because the invention proposes that the response dynamics of the wind turbine be stable, similar to those generated by photovoltaic solar panels.

[0049] DESCRIPTION OF THE INVENTION

[0050] To complement the description and in order to help better understand the characteristics of the invention, a set of figures of an illustrative and non-limiting nature is attached as an integral part of said description, as well as a glossary with the references used in the figures and abbreviations used in the equations accompanied by a description of each reference and abbreviation.

[0051] Glossary of reference numbers and brief description

[0052] (0) Vertical axis wind turbine, any of the prior art;

[0053] (01) Wind turbine (WT); of the vertical axis rotation type (VAWT) formed by a plurality of complex blades;

[0054] (02) Support column;

[0055] (1) Electromechanical (and electronic) system for vertical-axis wind turbines, object of the invention; it consists of an electromechanical subsystem, i.e., electrical and mechanical, and an electronic subsystem; although in the invention the concept "electromechanical" has been considered to encompass electrical-electronic and mechanical aspects, in the subsystems the terms have been separated for clarity;

[0056] (10) Electromechanical subsystem for vertical axis wind turbines; (11) Upper compartment;

[0057] (12) Lower compartment;

[0058] (13) Rotating support transmitting angular movement to the wind turbine blades;

[0059] (14) High precision micro planetary gear multiplier;

[0060] (15) MI synchronous machine, radial flux permanent magnet generator (PMSG); high-performance dual-shaft (hollow and protruding); one unit is available;

[0061] (16) M2 synchronous machine, with radial flux permanent magnets (Permanent Magnet Synchronous Generator, PMSG); high-performance dual-axis (hollow and protruding); one or more can be provided (16B, 16C, etc.);

[0062] (20) Underground power lines for synchronous machines (15, 16); of the type used to connect to electromechanical machines;

[0063] (30) Electronic subsystem for regulation and control of the electrical energy produced or consumed by the synchronous machine MI (15); of the variable frequency drive (VFD) type used for controlling the angular speed of an alternating current (AC) motor by means of controlling the frequency of the supply supplied to the motor, without regenerative function used in industrial motor applications (general purpose);

[0064] (301) Isolation transformer; feeds the input (Ll, L2, L3) of the frequency inverter (30) from the electrical network (60) isolating the reference from the neutral grounding of the network;

[0065] (302) Rectifier stage, converts alternating current and voltage (AC) into direct current and voltage (DC); three-phase bridge type with six diodes;

[0066] (303) DC bus with capacitor; DC circuit between rectifier and inverter;

[0067] (304) Inverter stage; converts direct current and voltage (DC) into alternating current and voltage (AC);

[0068] (305) Overvoltage limiting stage (Brake Chopper, BC); of the braking chopper type, it conducts the energy from the intermediate DC circuit of the converter to a braking resistor to limit the overvoltage; (306) External braking resistor (Dump Load, DL); in the event of an overvoltage on the internal DC bus of the drive, it dissipates the energy in the form of heat by the Joule effect;

[0069] (307) VDC terminal block; used to connect externally to the internal DC bus of the frequency inverter (30);

[0070] (308) AIVF terminal block; used to enter the speed / frequency reference of the output (T1 / U,T2 / V,T3 / W) of the frequency inverter (30) through an analog signal of 0-10 VDC;

[0071] (40) Electronic subsystem for conditioning the electrical energy produced by synchronous machines (15, 16), before being poured into an electrical network (On-Grid) (60);

[0072] (401) On-Grid inverter stage; converts direct current and voltage (DC) into conditioned alternating current and voltage (AC) for delivery to the electrical grid; conventional inverter type without MPPT function used in photovoltaics (general purpose);

[0073] (402) Rectifier stage, converts alternating current and voltage (AC) into direct current and voltage (DC); of the three-phase bridge type with six diodes;

[0074] (50) Programmable logic control electronic subsystem;

[0075] (501) Programmable logic controller (PLC); equipped with a mini display for control and monitoring;

[0076] (502) Anemometer sensor; its function is to measure wind speed through an analog output, e.g.: 0-25 m / s > 0-10V DC;

[0077] (503) MI synchronous machine contactor (15); of the type used in three-phase to connect and disconnect electrical machines;

[0078] (504) MI voltage sensor (15); its function is to measure the voltage through an analog output, e.g.: 0-400V AC to 0-10V DC;

[0079] (505) MI current sensor (15); its function is to measure the intensity of the electric current through an analog output, e.g.: 0-25A AC to 0-10V DC;

[0080] (506) M2 synchronous machine contactor (16); of the type used in three-phase to connect and disconnect electrical machines;

[0081] (507) Voltage sensor M2 (16); its function is to measure the voltage by means of an analog output, e.g.: 0-400V AC to 0-10V DC; (508) Current sensor M2 (16); its function is to measure the intensity of the electric current by means of an analog output, e.g.: 0-25A AC to 0-10V DC;

[0082] (60) Electrical, distribution or transport network;

[0083] (100) Blade tip fin; upper and lower ends of the plurality of blades that make up the wind turbine (01), object of the invention;

[0084] (Pl) Electromechanical procedure for operating a wind turbine (01) at the maximum power point (Maximum Power Point Tracking, MPPT) for the case of connection to an electrical grid (On-Grid), by using the device (1) for its implementation; Controller program (501);

[0085] (BA) Leading edge;

[0086] (EX) Extrados;

[0087] (IN) Intrados.

[0088] Glossary of abbreviations and brief description

[0089] C p Power coefficient, dimensionless; p w Air density, in kg / m 3 ; 1.29 kg / m 3 ;

[0090] TO WT Area swept by the turbine, in m 2 Wind speed, in m / s;

[0091] R Radius of the blade, in m;

[0092] (J WT Angular velocity of the wind turbine, in rad / s; n WT Angular velocity of the wind turbine, in rpm;

[0093] P WT Wind turbine power, in kW; i Multiplication ratio, dimensionless;

[0094] V15 / rpm Machine output voltage parameter 15 for each rpm, in V / rpm;

[0095] V16 / rpm Output voltage parameter of machine 16 for each rpm, in V / rpm; fmax Maximum output frequency parameter of the variable speed drive; in

[0096] Hz; e.g.: 599 Hz;

[0097] NP Number of poles of a synchronous machine, dimensionless; e.g.: from 44 to

[0098] 110; AIVF Analog input voltage-frequency ratio; 0 to 10 VDC;

[0099] HW Hardware; HW is equal to 1 (501) if the status of the programmable logic controller (PLC) (501) is correct;

[0100] KM1 Synchronous machine constant Ml(15); f (Vw) Function of wind speed;

[0101] Fs Lift force;

[0102] FE Levitation force;

[0103] CE Lift coefficient;

[0104] CD Coefficient of resistance;

[0105] ANG Angle, in (°); of the blade tip fin.

[0106] Brief description of the figures

[0107] Figure 01 (FIG.01) shows an elevation view of any prior art vertical axis wind turbine (0), equipped with an electromechanical system for vertical axis wind turbines (1) object of the invention; Figure 02 (FIG.02) shows a sectional view of an electromechanical subsystem for vertical axis wind turbines (10) object of the invention, in which a high precision micro planetary gear multiplier (14) can be seen in an upper compartment (11); Figure 03 (FIG.03) shows a sectional view of an electromechanical subsystem for vertical axis rotation wind turbines (10) object of the invention, in which a synchronous machine (15) coupled to the multiplier (14) can be seen in an upper compartment (11); this machine (15) is responsible for forcing operation at the maximum power point (MPPT) in the case of connection to an electrical network (On-Grid); Figure 04 (FIG.04) shows a sectional view of an electromechanical subsystem for vertical axis rotation wind turbines (10) object of the invention, in which a synchronous machine (16) coupled to the machine (15) can be seen in a lower compartment (12); Figure 05 (FIG.05).- shows a sectional view of an electromechanical subsystem for vertical axis rotation wind turbines (10) object of the invention, in which a synchronous machine (16B) coupled to the machine (16) can be seen in a lower compartment (12); Figure 06 (FIG.06).- shows a graph "Power Coefficient (Cp) - Angular velocity of the wind turbine (nwr)" involved in the procedure to operate at the maximum power point (Maximum Power Point Tracking, MPPT) for the case of connection to an electrical grid (On-Grid), by using the device (1) for its implementation; Figure 07 (FIG.07) shows a graph where the different operating zones (A and B) of the electromechanical system for vertical axis rotation wind turbines, object of the invention (1) are shown; Figure 08 (FIG.08) shows a multi-wire electrical diagram of the electromechanical (and electronic) system for vertical axis wind turbines, object of the invention (1); Figure 09 (FIG.09).- shows a GRAFCET diagram of a controller program (Pl l) to carry out the electromechanical and electronic procedure (Pl) of operation at the maximum power point (MPPT) for the case of connection to an electrical grid (On-Grid), by means of the use of the device (1) for its implementation; programmed in a programmable logic controller (501). In stage El.l to facilitate its reading, equation 12 is shown schematically; Figure 10 (FIG.10). shows the aerodynamic profile type cross section of a blade tip fin (100) of the upper and lower ends of the plurality of blades that make up the wind turbine (01), object of the invention.

[0108] Detailed description of the invention and detailed exposition of a preferred embodiment of the invention

[0109] A preferred embodiment of the invention is described in detail, among the different possible alternatives, by enumerating its components, as well as their functional relationship based on references to the figures, which have been included, for illustrative and non-limiting purposes, according to the principles of the claims.

[0110] Reference is made to the figures as necessary in order to obtain a better understanding of what is shown therein. The invention relates to an electromechanical system for vertical axis wind turbines (1) and a method for its implementation (Pl), of the type that incorporates an electronic regulation and control system to pursue its operation at the maximum power point (MPPT) and an electronic system for conditioned dumping of the generated electrical energy into an electrical grid (On-Grid) (FIG.01), and which in a preferred non-limiting embodiment is characterised in that it comprises:

[0111] An electromechanical subsystem for vertical axis rotation wind turbines (10) (FIG.02-05), containing the following elements:

[0112] - an upper compartment (11) consisting of a housing located at the top of a lower compartment (12) and containing a high-precision micro-planetary gear multiplier (14), which has a double hollow and protruding shaft. On the one hand, the upper protruding shaft is coupled to a rotating support (13) that transmits angular movement to the blades of the wind turbine (01) (FIG.02). On the other hand, the lower hollow shaft is inserted into a high-performance double-axis (hollow and protruding) radial flux permanent magnet MI synchronous machine (PMSG), the machine (15) being supported by the multiplier (14) in order to reduce mechanical stresses due to vibration (FIG.03).The machine (15) is reversible, operating as a motor in order to set the angular speed of the turbine (01) at a set speed corresponding to the maximum power coefficient for each incident wind speed (see FIG.06), that is, operation at the maximum power point (MPPT) is recommended in an electromechanical mode; simultaneously with the above, the machine (15) works as a generator when the wind speed exceeds the set one; a lower compartment (12) consisting of a housing located in the upper part of the support column (02) and containing a synchronous machine M2 (16), or a plurality of them (16, 16B, . . .), of permanent magnet radial flux (PMSG); of high performance double axis (hollow and protruding). The machine (16) is coupled to the lower hollow shaft of the machine (15) and is supported by the upper part of the compartment (12) (see FIG.03-04).The machine (16B) and subsequent ones that are required are supported by the machine (16) in order to reduce mechanical stress due to vibration (FIG.05). The machines (16) are operated exclusively as a generator.

[0113] In the present invention, maximum energy extraction is advocated by operating in two different sections (FIG. 07). To this end, in the first section of low-medium winds (3-9 m / s), called section A, which is characterized by being low in energy and having very low-low Cp (FIG. 06) but being the section that occurs most frequently (Weibull distribution), it is advocated that a frequency converter (30) be provided which, by means of the machine (15) functioning as a motor, causes the wind turbine (01) to rotate at the angular velocity (n WT) for a given wind speed and that makes the captured power maximum when for a wind speed higher than the one recorded, the machine (15) automatically switches to operate as a generator at the maximum power point (MPPT). In the second section of high winds (> 9 m / s), called section B, which is very energetic and has high Cp (FIG. 06) but is the least frequent section, it is recommended that a machine (16) be available operating only as a generator without requiring an expensive inverter (30), optimizing the cost-generation binomial.

[0114] Initially, the wind turbine (01) can be supplied with only one MI synchronous machine (15) for low-wind locations. In addition, having a system that can incorporate one or a plurality of M2 synchronous machines (16) has the technical advantage of allowing a standardized scaling in the manufacture of wind turbines (01) of different sizes, as well as making it possible to expand existing turbines (01).

[0115] In the present invention, maximum energy extraction is advocated by means of a synchronous machine power Ml(15) that will be given by equation 8 as detailed in the following paragraph. Optimum power of the synchronous machine MI (15), which advocates the invention

[0116] The wind power is given by equation 1:

[0117] Of the energy that the wind possesses, only 59% (Betz limit, 19 / 27) can be extracted by an ideal wind turbine (01), so the power of a real turbine (01) is lower and is given by equation 2:

[0118] The power coefficient (Cp) for a vertical axis wind turbine (VAWT) (01) consisting of a plurality of complex blades depends on the specific speed (TSR) represented by . The TSR is given by equation 3:

[0119] AND C . (3)

[0120] The angular velocity (n WT ) of this type of wind turbine (01) obtained by wind tunnel testing that makes the captured power maximum for a given wind speed is: n WT [rpm] = C1 • V w + C2 Eq. (4) being:

[0121] Cl= 1.9371; C2= 0.40857; values ​​obtained by experimentation and which have been found to be optimal for this type of turbine (01).

[0122] The power coefficient (Cp) that maximizes the power captured from the wind is given by equation (5): being:

[0123] C3= 0.00004393144; C4= 0.00001691435; C5= 0.0001567958; C6= 0.00001851985; values ​​obtained by experimentation and which have also been found to be optimal for this type of turbine (01).

[0124] By setting the nominal power PWT [kW] that is desired to be obtained from the turbine (01), the power of the synchronous machine M2 (16) is determined (or the power of the machines together (16, 16B, ...) in the case that there are several), knowing the air density (Pi ), ​​the swept area (A^) and the nominal power coefficient (Cp nominal) for this type of turbine (obtained by wind tunnel testing) the nominal wind speed (Vw) required is obtained by means of equation 6:

[0125] Applying Vw to Eq.4 gives the nominal angular velocity (nwT) of the turbine.

[0126] It has been found that a nominal power coefficient of the synchronous machine MI (15) equal to half of the nominal Cp of the turbine (01) surprisingly predicts the maximum power extracted from wind.

[0127] From Eq.5 we can calculate the angular velocity nwr, in rpm, for the previous optimal Cp MI (15) and from Eq.4 the necessary wind speed (Vw), which turns out to be half the cube of the nominal, to finally obtain the optimal power of the synchronous machine MI (15) using the following equation:

[0128] For a preferred embodiment of the invention among the different possible alternatives, using a turbine (01) with the following characteristics:

[0129] - Model: Vertical Axis Wind Turbine KLiUX Zebra-Plus, 9 blades;

[0130] - Rotor height: 3.81 m;

[0131] - Rotor diameter: 3.1 m;

[0132] - Swept area: 11.81 m 2 ;

[0133] - Nominal power: 4 kW in a single permanent magnet synchronous generator.

[0134] We obtain for a power P WT[kW] of 4 kW, i.e. the nominal power of the synchronous machine M2 (16), an air density p w of 1.29 kg / m 3 , a swept area A WT 11.81 m 2 and a Cp of 0.42 we obtain a speed of Vw of 10.8 m / s rotating the turbine at an angular speed nwr of 21.3 rpm. Applying equation 7 we obtain an optimal Cp of 0.21 obtaining a Vw of 8.5 m / s, rotating the turbine at an angular speed nwr of 16.9 rpm, and resulting in an optimal power of the synchronous machine MI (15) of 1 kW *

[0135] (*) Results obtained by the UNIVERSITY OF LA RIOJA during an experimentation campaign in a wind tunnel and in the field during the years 2021-22. Using this optimal value for the power of the MI synchronous machine (15), an increase in the generated energy of 25% higher was obtained than with other power values. of underground electrical supply lines (20) that have the purpose of electrically connecting the equipment (30, 40) with the synchronous machines (15,16). An electronic subsystem for regulating and controlling the electrical energy produced and consumed by the MI synchronous machine (15), composed of a frequency inverter (30) containing the following elements (FIG.08):

[0136] - Isolation transformer (301); it supplies the frequency converter (30) by isolating the reference from the neutral grounding of the electrical network (60);

[0137] - Rectifier stage (302); converts alternating current and voltage (AC) into direct current and voltage (DC);

[0138] - DC bus (303) equipped with capacitor; DC circuit between the rectifier and the inverter;

[0139] - Inverter stage (304); converts direct current and voltage (DC) into alternating current and voltage (AC);

[0140] - Overvoltage limiting stage (305), brake chopper (BC) type; it conducts the energy from the intermediate DC circuit of the converter to a braking resistor to limit the overvoltage;

[0141] - Braking resistor (306); in case of overvoltage on the internal DC bus of the drive, it dissipates energy in the form of heat by the Joule effect;

[0142] - VDC terminal block (307); used to connect externally to the internal DC bus of the frequency inverter (30);

[0143] - AIVF terminal block (308); used to enter the speed / frequency reference of the output (Tl / U, T2 / V, T3 / W) of the frequency inverter (30) through an analog signal of 0-10 VDC.

[0144] The frequency inverter (30) through the output (Tl / U, T2 / V, T3 / W) feeds the synchronous machine MI (15) making it operate as a motor at an angular speed based on a setpoint given by equation 12 as detailed in the following paragraph and which corresponds to the maximum power coefficient for each incident wind speed pursuing a maximum power point tracking (MPPT) in an electromechanical way. When the wind speed exceeds the setpoint, the machine (15) starts to operate as a generator delivering through the output (Tl / U, T2 / V, T3 / W), which is now functionally an input, the energy captured by the wind until it reaches the internal DC bus and exits through the VDC oven (307) being conducted to the first input (1VDC) of the conventional inverter (401) that conditions it and pours it through its output to the electrical network (60), distribution or transport.

[0145] Voltage-frequency relationship (AIVF) for the purpose of setting the optimal speed of the MI synchronous machine (15), which advocates the invention

[0146] The angular velocity (n WT ) of this type of wind turbine (01) that makes the captured power maximum for a wind speed is given by equation 4: n WT [rpm] = Cl - V w + C2

[0147] The angular velocity of the machine (15) is: n Mi5 [rpm] = i ■ n WT Eq. (9)

[0148] The electrical frequency of the machine (15) to rotate at the angular speed is:

[0149] The value of the PLC analog output (501) that is connected to the analog input (AIVF) of the frequency converter in order to set the speed of the machine (15) is: An electronic subsystem for conditioning (40) the electrical energy produced by the synchronous machines (15, 16), before being poured into an electrical network (On-Grid) (60), which contains the following elements (FIG.09):

[0150] - On-Grid inverter stage (401); converts direct current (DC) and voltage into conditioned alternating current (AC) and voltage for delivery to the electrical grid; conventional inverter type without MPPT function used in photovoltaics (general purpose);

[0151] - Rectifier stage (402), converts alternating current and voltage (AC) into direct current and voltage (DC); of the three-phase six-diode bridge type;

[0152] The synchronous machine M2 (16) that always works as a generator, through the rectifier (402) converts its voltage from AC to DC to deliver the generated energy to the second input (2VDC) of the conventional inverter (401) that conditions it and pours it through its output to the electrical network (60), for distribution or transport.

[0153] An electronic programmable logic control subsystem (50), containing the following elements (FIG.08):

[0154] - Programmable logic controller (501); equipped with a mini display for control and monitoring;

[0155] - Anemometer sensor (502); its function is to measure the wind speed through an analog output, e.g.: 0-25 m / s > 0-10V DC;

[0156] - MI synchronous machine contactor (503); of the type used in three-phase to connect and disconnect electrical machines;

[0157] - MI voltage sensor (504); its function is to measure the voltage through an analog output, e.g.: 0-400V AC to 0-10V DC;

[0158] - MI current sensor (505); its function is to measure the intensity of the electric current through an analog output, e.g.: 0-25A AC to 0-10V DC; - M2 synchronous machine contactor (506); of the type used in three-phase to connect and disconnect electrical machines;

[0159] - Voltage sensor M2 (507); its function is to measure the voltage through an analog output, e.g.: 0-400V AC to 0-10V DC;

[0160] - M2 current sensor (508); its function is to measure the intensity of the electric current through an analog output, e.g.: 0-25A AC to 0-10V DC.

[0161] An electrical network (60), for distribution or transport (FIG.08), into which the generated electrical energy is poured in a conditioned manner.

[0162] In the state of the art, different types of blade tip fins (100) or winglets are known, the function of which is to reduce the wing tip vortices, in the case of aircraft, and the blade vortices, in the case of aeroturbines, thereby reducing the aerodynamic resistance of the wing or blade and which are characterized in that they lack the capacity to generate any lift force, since when placed on a vertical or inclined plane this force is horizontal or inclined.

[0163] In another preferred embodiment (FIG. 10) the wind turbine (01) is provided with blade tip fins (100) arranged horizontally, or aesthetically at an angle (ANG) with respect to the horizontal plane, and whose cross section is a type of aerodynamic profile that when each fin moves through the air is capable of creating a vertical lift force (Fs) upwards in order to create a joint levitation force (FL) on the wind rotor (01) compensating for its weight and reducing rotational friction. These fins (100) are arranged both on the upper and lower part of the rotor (01) with the leading edge (BA) oriented in the direction of rotation of the rotor (01) and on both sides the extrados (EX) facing upwards and the intrados (IN) facing downwards so that each of the lift forces (Fs) are upwards.

[0164] Since the fins (100) in the state of the art are designed to reduce turbulence and the invention advocates producing levitation, the type of aerodynamic profile must be appropriate for low wind speed and high turbulence, so it has been discovered in an experimental campaign that the profile that presents the best performance is the SG6043 type with a CL / CD coefficient ratio of 82.5% for an angle of attack (a) of 4.85°. For a fin (100) arranged horizontally the levitation force is maximum and arranged vertically it is zero, in the case that for aesthetic reasons it is placed at an angle (ANG) with respect to the horizontal plane of 0. o The levitation force will be expressed by the following equation:

[0165] FL = FL MXX • eos ANG Ec. (13)

[0166] Electromechanical procedure for the operation of a wind turbine (01) at the maximum power point (Maximum Power Point Tracking, MPPT) for the case of connection to an electrical network (On-Grid) (Pl), by using the device (1) for its implementation (FIG.09)

[0167] An electromechanical procedure for the operation of a wind turbine (01) at the maximum power point (MPPT) is described in detail for the case of connection to an electrical network (On-Grid) (Pl) that uses a device (1) for its implementation, by enumerating the stages to be executed according to the indicated order.

[0168] The invention relates to an electromechanical method for operating a wind turbine (01) at the maximum power point (MPPT) in the case of connection to an electrical grid (On-Grid) (Pl) by means of the use of the device (1) for its implementation, of the type that interacts with a series of electromechanical actuation elements and electronic instrumentation and control elements, which uses the electromechanical and electronic system for vertical rotation axis wind turbines (1) implemented in a controller program (Pl 1) installed in a programmable logic controller (501), being characterized in that it comprises at least the following stages:

[0169] STAGE “E0”. Start

[0170] The first stage, stage “E0”, consists of a start stage which is initially accessed if the hardware status parameter (HW) is correct and is accessed cyclically when the stages “El. l” or “E2.1” are completed, and incorporates means of communication with the anemometer sensor (502), with the contactors (503, 506) and with the AIVF oven (308) of the frequency inverter (30). Disconnecting the MI machine (15)

[0171] This stage is accessed directly from the “EO” stage or if the following conditional statement is met while in the “El.l” stage:

[0172] If {Vw < (VwMIN)} or {Vw > (VwOPT)} then {RESET 503} the contactor coil (503) is deactivated and the electrical disconnection of the synchronous machine MI (15) occurs.

[0173] STAGE “El.l”. Operation of the synchronous machine MI (15) as a motor at the maximum power point so that when the machine (15) works as a generator the power captured by the wind turbine (01) is maximum for each wind speed

[0174] Correspondence with zone A (FIG.07). According to the reading of the anemometer sensor (502) from stage “El.O” if the following conditional statement is met:

[0175] If {Vw > (VwMIN)} or {Vw < (VwOPT)} then {SET 503} in this intermediate stage the contactor coil (503) of the synchronous machine MI (15) is activated and the analog value of the analog output of the PLC (501) resulting from applying equation 12 is sent to the oven AIVF (308) of the frequency inverter (30):

[0176] AZ7F M15 [0 - íorac] being:

[0177] Cl= 1.9371; C2= 0.40857; values ​​obtained by experimentation and which have been found to be optimal for this type of turbine (01). so that the frequency vacuum (30) by means of the machine (15) functioning as a motor causes the wind turbine (01) to rotate at the angular speed (n WT ) which makes the captured power maximum for a given wind speed so that when the wind speed exceeds the set speed, the machine (15) works as a generator at the maximum power point (MPPT).

[0178] STAGE “E2.0”. Disconnection of the M2 machine (16)

[0179] This stage is accessed directly from stage “E0” or if the following conditional statement is met while in stage “E2.1”:

[0180] If {Vw < (VwOPT)} or {Vw > (VwMAX)} then {RESET 506} the contactor coil (506) is deactivated and the electrical disconnection of the synchronous machine M2 (16) occurs.

[0181] STAGE “E2.1”. Operation of the synchronous machine M2 (16) as a generator Correspondence with zone B (FIG.07). According to the reading of the anemometer sensor (502) from stage “E2.0” if the following conditional statement is met:

[0182] If {Vw > (VwOPT)} OR {Vw < (VwMAX)} then {SET 506} the contactor coil (506) of the synchronous machine M2 (16) is activated, causing it to function as a generator, capturing the corresponding wind power.

Claims

CLAIMS 1. Electromechanical system for vertical axis rotation wind turbines (1) of the type that incorporates an electronic regulation and control system to pursue its operation at the maximum power point (MPPT) and an electronic system for conditioned dumping of the generated electrical energy into an electrical network, which is characterized in that it comprises: An electromechanical subsystem for vertical axis wind turbines (10), containing the following elements: - an upper compartment (11) consisting of a housing located in the upper part of a lower compartment (12) and containing a micro planetary gear multiplier (14), this having a double hollow and protruding shaft. On the one hand, the upper protruding shaft is coupled to a rotating support (13) transmitting angular movement to the blades of the wind turbine (01). On the other hand, the lower hollow shaft is inserted into a radial flux permanent magnet MI synchronous machine (PMSG) (15) with a double hollow and protruding shaft, the machine (15) supporting the multiplier (14).The machine (15) is reversible, operating as a motor in order to set the angular speed of the turbine (01) at a set speed corresponding to the maximum power coefficient for each incident wind speed, that is, operating at the maximum power point (MPPT) in an electromechanical manner and simultaneously the machine (15) operates as a generator when the wind speed exceeds the set speed. - a lower compartment (12) consisting of a housing located in the upper part of the support column (02) and containing a synchronous machine M2 (16), or a plurality of them (16, 16B, . . .), of radial flux permanent magnets (PMSG) with a double hollow and protruding shaft. The machine (16) is coupled to the lower hollow shaft of the machine (15) and is supported by the upper part of the compartment (12). The machine (16B) and subsequent ones that are required are supported by the machine (16) and are operated exclusively as a generator; and whose power of the synchronous machine MI (15) is given by the following: A set of underground power lines (20) that have the purpose of electrically connecting the equipment (30, 40) with the synchronous machines (15,16). An electronic subsystem for regulating and controlling the electrical energy produced and consumed by the synchronous machine MI (15), composed of a frequency inverter (30) containing the following elements: - Isolation transformer (301); it supplies the frequency converter (30) by isolating the reference from the neutral grounding of the electrical network (60); - Rectifier stage (302); converts alternating current and voltage (AC) into direct current and voltage (DC); - DC bus (303) equipped with capacitor; DC circuit between the rectifier and the inverter; - Inverter stage (304); converts direct current and voltage (DC) into alternating current and voltage (AC); - Overvoltage limiting stage (305), brake chopper (BC) type; it conducts the energy from the intermediate DC circuit of the converter to a braking resistor to limit the overvoltage; - Braking resistor (306); in case of overvoltage on the internal DC bus of the drive, it dissipates energy in the form of heat due to the Joule effect; - VDC terminal block (307); used to connect externally to the internal DC bus of the frequency inverter (30); AIVF terminal block (308); used to input the speed / frequency reference of the output (Tl / U, T2 / V, T3 / W) of the frequency inverter (30) through an analog signal of 0-10 VDC. An electronic subsystem for conditioning (40) the electrical energy produced by the synchronous machines (15, 16), before being poured into an electrical network (60), which contains the following elements: - Grid-connected inverter stage (401); converts direct current and voltage (DC) into conditioned alternating current and voltage (AC) for delivery to the grid; conventional inverter type without MPPT function; - Rectifier stage (402), converts alternating current and voltage (AC) into direct current and voltage (DC); three-phase bridge type with six diodes. A programmable logic control electronic subsystem (50), containing the following elements: - Programmable logic controller (501); equipped with a mini display for control and monitoring; - Anemometer sensor (502); its function is to measure wind speed through an analog output; - MI synchronous machine contactor (503); of the type used in three-phase to connect and disconnect electrical machines; - MI voltage sensor (504); its function is to measure the voltage through an analog output; - MI intensity sensor (505); its function is to measure the intensity of the electric current through an analog output; - M2 (506) synchronous machine contactor; of the type used in three-phase to connect and disconnect electrical machines; - M2 voltage sensor (507); its function is to measure voltage using an analog output; - Intensity sensor M2 (508); its function is to measure the intensity of the electric current through an analog output. An electrical network (60), distribution or transport.

2. Electromechanical system for vertical axis rotation wind turbines (1), according to claim 1, characterized in that the wind turbine (01) is provided with blade tip fins (100) arranged horizontally, or aesthetically at an angle (ANG) with respect to the horizontal plane, and whose cross section is an SG6043 type aerodynamic profile with an angle of attack (a) of 4.85 ° which, as each fin moves through the air, is capable of creating an upward vertical lift force (Fs) in order to create a joint levitation force (FL) on the wind rotor (01), compensating for its weight and reducing rotational friction.

3. Electromechanical method for operating a wind turbine (01) at the maximum power point (MPPT) in the case of connection to an electrical grid (Pl) by using the device (1) for its implementation, according to one of claims 1 to 2, of the type that interact with a series of electromechanical actuation elements and electronic instrumentation and control elements, which uses the electromechanical and electronic system for vertical axis rotation wind turbines (1) implemented in a controller program (Pl l) installed in a programmable logic controller (501), the method comprising the following steps: - Step "E0". Start; - Step "E1.0". Disconnection of the machine MI (15); - Step "E2.0". Disconnection of the machine M2 (16); - Step "E2.1". Operation of the synchronous machine M2 (16) as a generator; said method being characterized in that it comprises the following intermediate step: Stage “El.l”. Operation of the synchronous machine MI (15) as a motor or as a generator at the maximum power point which makes the captured power by the wind turbine (01) is maximum for each wind speed, consisting of that according to the reading of the anemometer sensor (502) from stage “E1.0” if the following conditional sentence is fulfilled: If {Vw > (ywMIN)} or {Vw < (VwOPT)} then {SET 503} the contactor coil (503) of the synchronous machine MI (15) is activated and the analog value of the analog output of the PLC (501) resulting from applying the following equation is sent to the AIVF oven (308) of the frequency inverter (30): AIVF M15 [o - íorac] where Cl= 1.9371 and C2= 0.40857; so that the frequency converter (30) through the machine (15) functioning as a motor causes the wind turbine (01) to rotate at the angular speed which makes the captured power maximum for a given wind speed so that when the wind speed exceeds the set speed, the machine (15) works as a generator at the maximum power point (MPPT).

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