DE102017006103A1 - Electrical and pneumatic control system - Google Patents

Abstract

The present invention relates to a control system for wind turbines, in particular small wind turbines with electrical and pneumatic control functionalities. A system with at least one compressor and various additional components is used in order to automatically control and regulate a wind energy plant as a whole cost-effectively and with high control quality, in particular in the event of overload situations. Various actuation movements are performed electropneumatically or limited in terms of maximum forces, moments, speeds and powers by establishing balance situations between the operating forces and the innovative pressure-controlled pneumatic cylinders or actuators. The control system includes novel novel functions for the brake, the rotor blade pitch, an alternative wind vane, and other features.

Description

Modern wind turbines are now available on the market in large numbers. They are usually equipped with elaborate and expensive mechanical, hydraulic and electrical control elements motors and gears for panning and rotor blade adjustment. Small wind turbines, on the other hand, are often equipped with simple mechanical and electrical control and regulation components which often provide insufficient or too slow control, or control of the equipment during normal operation or overload operation, i. allow too much wind. The present invention defines a compact and very high quality, i. fast, responsive to external loads (wind) and speeds control system, which is equipped with novel mechanical, pneumatic and electrical components and a comparatively cheap and reliable control of regenerative systems, especially wind turbines in operation and when exceeding the full load allows and thus smaller Wind turbines can be used economically. Furthermore, other secondary or actuating movements and functions or safety functions can be taken over by the novel system.

How it works:

• Gemäß Anspruch 1 weist das Steuerungssystem ein Pneumatiksystem zur Erzeugung oder Bereitstellung von Druckluft oder anderen komprimierten Gasen zur Steuerung einer Windenergieanlage auf, dass mindestens über einen Kompressor oder eine Pressluftversorgung oder mindestens ein Ventil oder Wasserabscheider oder Druckschalter oder Druckregler oder druckfeste Schläuche verfügt. Der Gasdruck kann alternativ auch über eine Gasflasche bereitgestellt werden und kann vorzugsweise mittels mindestens eines Druckreglers oder Druckschalters oder Drucksensors im Betrieb konstant gehalten und justiert werden, um Stellbewegungen zu ermöglichen und damit Begrenzungen von maximalen Kräften, Leistungen, Drehzahlen und Momenten zu realisieren. Erfindungsgemäß soll mit der Pneumatik ein sanftes Abregeln im Überlastbereich erreicht werden, indem die pneumatischen Kräfte in einen Gleichgewichtszustand mit den belastungsabhängigen Betriebskräften der Windenergieanlage gebracht werden, sodass automatische Ausweichbewegungen beim Überschreiten von Belastungsgrenzen ausgelöst werden:
• Gemäß Anspruch 2 ist zum Betrieb und zur Überwachung der WKA und des Pneumatiksystems eine elektronische Steuerung vorgesehen, die mittels elektrischer Ventile, Sensoren und Druckschalter den/die Systemdrucke und den Automatikbetrieb steuert und überwacht. Dazu sind gemäß Anspruch 3 vorzugsweise eine Fernbedienung, ein Wechselrichter zur Netzeinspeisung, ein Schwenkmotoranschluss diverse elektrische Komponenten (Sensoren) angeschlossen, sodass eine vorzugsweise softwaregestützte, vollautomatische Anlagenkontrolle möglich ist. Es ist dabei vorteilhaft, dass die Steuerung im Wesentlichen auf einer Steuerplatine zusammengefasst ist, die sich gut zugänglich im unteren Bereich des Mastes und nicht auf der Gondel befindet.
• Gemäß Anspruch 4 wird eine Versorgungsnetz-unabhängige Arbeitsweise der elektrischen Steuerung dadurch erreicht, dass diese mittels einer batteriegepufferten Kleinspannung (z.B. 24V DC) versorgt wird. Zum kontinuierlichen Nachladen der Batterie(en) wird ein eingebautes Ladegerät benutzt.

The electrical and pneumatic control system according to the invention is preferably used in classic types of wind turbines with horizontal axis of rotation, multiple, located on a rotor hub rotor blades, a mast, a pivotally mounted about a vertical axis nacelle with motorized pivot drive or alternatively with a wind vane to align with the wind , but can also be applied to other wind turbines such as vertical rotor systems. With the control system, the functions relevant for the operation and the overload behavior such as the pivoting movement, the brake system, the rotor blade adjustment and other pneumatic and electrical system components, controlled in such a way that both an automated normal operation, as well as a high-quality fast Abregelbetrieb under overload or automated stop with low cost and high control quality is realized. According pressurized pneumatic cylinders or actuators are arranged according to the invention at different points of the wind turbine and brought into a state of equilibrium to relevant operating forces, so that when exceeding the operating forces to automatic positioning movements of the system components and automatic force, torque, and speed limits, ie to a power limit comes. By adjusting the respective system pressure, the response points can be adjusted. By switching off the system pressure via one or more valves, a substantial or complete shutdown of the system can be initiated with the respective adjusting movement. With its cylinders or actuators, the system forms a quasi sum of adjustable and adjustable gas pressure springs, against the forces and moments of the wind, which yield when the permissible limit values are reached. The pneumatic forces offer over mechanical spring forces the additional advantage that in pressure-controlled systems after reaching the point of contact a very wide response of the respective positioning movement can be realized without the pressure or the force increases significantly. Thus, the adjusting movement is particularly effective:

• According to claim 1, the control system comprises a pneumatic system for generating or providing compressed air or other compressed gases for controlling a wind turbine, which has at least one compressor or a compressed air supply or at least one valve or water separator or pressure switch or pressure regulator or pressure-resistant hoses. The gas pressure may alternatively be provided via a gas cylinder and may preferably be kept constant and adjusted by means of at least one pressure regulator or pressure switch or pressure sensor during operation to allow adjusting movements and thus to realize limits of maximum forces, powers, speeds and moments. According to the invention, a gentle offsetting in the overload area is to be achieved with the pneumatic system by bringing the pneumatic forces into an equilibrium state with the load-dependent operating forces of the wind energy plant, so that automatic evasive movements are triggered when load limits are exceeded:
• According to claim 2, an electronic control is provided for operation and monitoring of the WKA and the pneumatic system, which controls the system pressure and the automatic mode by means of electrical valves, sensors and pressure switch and monitors. For this purpose, according to claim 3 preferably a remote control, an inverter for feeding power, a swivel motor connection various electrical components (sensors) connected, so that a preferably software-based, fully automatic system control is possible. It is advantageous that the controller is essentially summarized on a control board, which is good accessible at the bottom of the mast and not located on the gondola.
• According to claim 4, a supply network-independent operation of the electrical control is achieved in that it is supplied by means of a battery-backed low voltage (eg 24V DC). For continuous recharging of the battery (s) a built-in charger is used.

According to the invention, the pneumatic pressures and signals used for control and regulation purposes are guided via a rotary feedthrough with rotary seals in the unrestricted by more than 360 ° pivotable nacelle. This design allows a very reliable control and regulation of the wind turbine and the operation of a brake in the nacelle, as well as other functions in the nacelle, without sensitive electrical signals and - currents must be passed through a rotary feedthrough.

Advantages in the assembly, manufacture and installation provides the inventive embodiment of the rotary feedthrough according to claim 6, by various sensors for special operation of the WKA, in particular a speed sensor, angle sensor for detecting the nacelle direction, vibration sensor, temperature sensor u.a. are combined with the pneumatic rotary feedthrough for one or more compressed air conduits to form an integral subassembly. The sensors and signals of this multi-functional rotary feedthrough via cable and multi-plug are very easy to install and connected to the controller.

According to the invention, a very powerful and reliable main brake function with a spring brake according to the patent application DE 10 2009 010 671.5 intended. By means of the application filed here, a constant, reliable, automatically switchable, frost-proof system pressure for the braking system known from the prior application is provided according to claim 7.

According to claim 8, the control system is equipped with an independent, mechanical overspeed protection shutdown, which acts on the pneumatic pressure of the brake system. For this purpose, located on the rotor shaft or another rotating shaft in the region of the nacelle, a spring-loaded centrifugal weights tripping air valve, which blows off the compressed air of the spring brake at overspeed and thus activates the spring brake. According to the invention, it is particularly helpful if this protective mechanism, or the air valve by a return cylinder by means of compressed air, in accordance with the invention presented here, from below (without reaching the nacelle) is reset, so again closed.

In order to be able to operate the innovative control system without problems even in frost, a water separator (tank) is provided and many pneumatic components prevent freezing due to heating resistors automatically switched by the controller according to claim 9.

It is particularly advantageous to use the electropneumatic control system for limiting power, torque and rotational speed in overload operation, that is to say in case of too much wind, according to claim 10 and subsequent claims. According to claim 10, the rotor blades are mounted (approximately) their longitudinal axis rotatable (tiltable) on the rotor hub ( ). The rotational movement of a (each) sheet about an axis of rotation is supported by a lever and cylinder or actuator of the pneumatic system, so that the cylinder or actuator forms a pressure adjustable pneumatic abutment, or a spring buffer against the operating forces of the sheet, especially against the attacking shear forces F of the blade. For this purpose, an eccentric arrangement of the rotor blade surface, ie the point of application of the transverse force to the axis of rotation (tilting axis) of the blade is provided (see transverse force on the blade F, with lever arm h, ). Exceeding permissible maximum values of the wind pressure (ie, the lateral force F), the pneumatic biasing force of the cylinder / actuator is overcome and thus the tilt angle of the blade adjusted so that it comes to an effective change in the angle of attack and thus a reduction or limitation of the speed and power ,

According to claim 11, it is very advantageous if the rotor blades are mounted axially (displaceably), using the centrifugal forces of the rotor blade mass, on the rotor hub ( ). The mechanical arrangement of the system, including the inventively provided cylinder or actuator is chosen so that the axial displacement of the rotor blade using a linkage, deflection mechanism, deflection or similar machine elements is also deflected to a change in the tilt angle (angle of attack). Thus, a thrust-rotary motion takes place by the centrifugal force, so that the angle of attack of the sheet can yield here against the pneumatic bias of the system.

The adjustment of the tilt angle or the pushing movement may have single or common pneumatic cylinders or actuators. To deflect the thrust movement may be arranged, for example in the region of the lever linkage, a slope or the linkage arranged obliquely to the rotor blade axis and the rotor axis, such that the axial displacement of the sheet acts on one or the common pneumatic cylinder or actuator.

It is inventively provided that the maximum speed and power is limited by the system and a drain of the system pressure leads to an immediate tilting movement of the leaves and strong reduction in speed, ie a stop of the system or the achievement of a non-critical rest position.

Preferably, the force for rotor blade adjustment is applied within the rotating rotor hub or at least within the largely stationary nacelle of the cylinder (s) or actuators. This is achieved particularly advantageously by a short-setting cylinder or actuator within the rotor hub according to claim 12. This can be realized by a pneumatic cylinder with a large diameter or by an elastic, pneumatically acted upon hollow body (bellows, rubber spring buffer, hose) or a circumferentially clamped, elastic, one-sided pressurized disc (a possible embodiment shows ). Likewise, a tire, similar to patent application DE 10 2009 010 671.5 (same inventor) are used to generate a large, pneumatically actuated force as an actuator for the pitch adjustment. Instead of a single, common cylinder, a single cylinder or actuator for each blade may be provided for all rotor blades. For pneumatic supply of (the) cylinder or actuators a compressed air supply line through the rotor shaft and a rotary feedthrough on the rotor shaft and a further rotary feedthrough in the nacelle pivot bearing is provided.

For transmitting the actuating force from the cylinder or actuator to the rotor blades, a linkage, gear or transmission mechanism is provided, which serves in the simplest case of attached to the round tubes of the rotor blade bearing lever arms or push rods for transmitting the pneumatic force and tilting movement.

The arrangement of the cylinder / actuator for the adjustment movement in the hub or rotor shaft offers great advantages, but has the disadvantage that the required compressed air must be guided into the rotating shaft. Alternatively, according to claim 13, the cylinder or actuator may also be arranged on the substantially stationary nacelle, wherein the force or adjusting movement is then introduced into the rotating rotor shaft by a tension / compression rod located centrally in the rotor shaft by means of a rotary bearing arranged axially relative to the rotor shaft ( transferred), wherein the pressure rod can also be a hydraulic pressure fluid with rotary pressure seal.

As an alternative to motorized rotary actuators, a (smaller) wind energy plant can also be equipped with a wind vane that regularly tracks the wind system. In systems of this construction, ie without motor pivot drive, the pneumatic system according to claim 14 can also act on the pivotal movement of the wind vane relative to the nacelle. For this purpose, a cylinder or actuator is arranged so that e.g. an envisaged return spring, the movably arranged wind vane laterally pivoted when the pneumatic force in the cylinder / actuator is exceeded by forces or moments of the wind or the pneumatic pressure for stopping the system is turned off.

Of manifold advantage is when the wind turbine has a central drive with generator in the substructure or a mast integrated generator according to claim 15. For example, in such an arrangement, the generator can be arranged resting in the mast, so that no rotary feedthroughs are required for the power cable or data cable, as in the nacelle in this design, no electrical components (pneumatic only) must be. This significantly increases the long-term reliability. Preferably, the generator can be suspended in elastic vibration damping elements.

In particular, in wind turbines with central drive according to claim 15 or mastintegriertem generator and a motorized pivot drive of the nacelle about the vertical axis, a cylinder or actuator according to claim 16 also be arranged so that the motor pivotal movement of the nacelle is exerted or supported via a cylinder or actuator, such When the gondola exceeds a maximum torque in the central main drive (generator), it automatically pivots out of the wind against the pneumatic support force.

In accordance with claim 17, the required rotational and / or thrust movement of the (the) rotor blades is particularly low friction, durable and cheap realized by means of anodized aluminum tubes, or surfaces in plastic plain bearing bushes. These may preferably be designed as round tubes.

With regard to the overall quality and performance of the system is further improved according to claim 18 by the mast for vibration reduction and to increase the stability with generous node stiffening and elastic decoupling of the system components is equipped, as in the existing patent applications DE 10 2012 009 849.9 and DE 10 2012 009 850.2 (same inventor and applicant), it is not relevant here whether the system has a central drive or not.

According to claim 19 according to the invention for the various actuating movement of the claims, or holding the sheet in the normal position against the centrifugal force of the rotor blades return springs or connected to the pneumatic system pneumatic springs or elastomer springs are provided, and corresponding end stops for the working and rest positions of the actuating movements ,

The control and regulation system achieves a high quality of control, in particular in overload operation and for automated stopping. Even within normal operation, a significant speed adjustment and thus adaptation to different generator voltages to achieve high efficiency at variable wind speeds is required. In particular, at low wind speeds, the rectified voltage of the grid feed generator must be increased. This is achieved by an inverter according to the invention as claimed in claim 20 with an additional voltage step-up and control electronics (a step-up converter), the control electronics being dependent on the electrical control of the invention for optimum operating points, i. an optimal performance characteristic, can be controlled. Due to a high required performance with simultaneously low induced electrosmog, the DC boost converter is preferably carried out not with a single combination of a clocked power semiconductor with an inductance, but from a number of multiple power semiconductors with respective inductors whose clock signals are constructed offset in time. Thus, several smaller partial currents (pulse currents) of the combinations add successively to an EMC-technically uncritical total current.

LIST OF REFERENCE NUMBERS

1

rotor hub

2

rotor blade

3

Rotor axis (shaft)

4

Rotary bearing rotor blade

5

Lever / linkage for tilting movement

6

Cylinder, actuator

7

Rotary feedthrough rotor

8th

pneumatic control

9

electrical control

10

remote control

11

inverter

12

return spring

13

Rotary union gondola

14

gondola

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009010671 [0005, 0012]
• DE 102012009849 [0019]
• DE 102012009850 [0019]

Claims (20)

Control and regulating system for a wind turbine with a rotor, a mast, a foundation, an energy converter (eg generator) and a rotatably mounted about the vertical axis, pivotable in the respective wind direction, nacelle, characterized in that a pneumatic system with at least one compressor or at least one valve or water separator or pressure switch or pressure regulator or pressure-resistant hoses is added, which provides at least one defined, in normal operation largely constant and preferably adjustable gas pressure for positioning movements or essential control tasks of the wind turbine. Control system according to Claim 1 , characterized in that an electrical / electronic control is provided, which controls the pneumatic system and / or the wind turbine automatically, actuated and monitored. Control system according to Claim 1 , characterized in that the electronic control provides functions for operating an electric or pneumatic rotary actuator of the nacelle (motor) or a remote control or inverter or for measuring wind speed and direction or for monitoring measured values such as pressures and temperatures. Control system according to Claim 1 , characterized in that the electronic control means of a battery buffering, preferably with low voltage (eg 24V DC), at least temporarily can work independently of the mains. Control system according to Claim 1 , characterized in that a rotary union with rotary sealing elements for introducing the / the pneumatic pressure / pressure is provided in the rotatably mounted nacelle. Control system according to Claim 1 , characterized in that the rotary feedthrough is combined to form an assembly with other electrical functions of the controller, such as a Drehzahlmessaufnehmer or Winkelmessaufnehmer, or Vibration Transducer or Temperaturaufnehmern and is preferably mounted in the region of the pivotal mounting of the nacelle. Control system according to Claim 1 , characterized in that at least one pneumatic pressure for release (solution) of a spring-loaded brake system is provided, as defined for example in patent application DE 10 2009 010 671.5 (the same inventor). Control system according to Claim 1 , characterized in that at least one pneumatic pressure for a return movement of an overspeed protection mechanism is provided and the protective mechanism itself is preferably triggered by mechanical centrifugal elements and a Luftauslasshahn, which blows off the brake pressure at overspeed. Control system according to Claim 1 , characterized in that an antifreeze system of heating resistors is provided on individual or a plurality of pneumatic (or electrical) system components, which is automatically switched (temperature-controlled) by the controller. Control system according to Claim 1 , characterized in that at least one, preferably adjustable or variable pneumatic pressure for generating a force is provided, with which the rotatable about its longitudinal axis (tiltable) on the rotor hub rotor blades are biased against the transverse force F of the blade (wind). Control system according to Claim 1 , characterized in that at least one, preferably adjustable or variable pneumatic pressure is provided for generating a force with which an adjusting movement of the rotor blades in the longitudinal direction of the sheet due to the centrifugal force is taken, such that a displacement via a linkage or deflection mechanism to a Rotary movement (tilting movement) of the blade in its pivot bearing leads. Control system according to Claim 1 , characterized in that for generating the force for the adjustment movement (s) of the rotor blades a pneumatic cylinder or elastic, pneumatic actuator (eg pneumatic bellows, tires, hose, ...) is provided, in or on the rotating rotor hub or the rotor shaft is arranged and supplied via a rotary seal (rotary feedthrough) through the rotor shaft with pneumatic pressure. Control system according to Claim 1 , characterized in that alternatively to Claim 12 the force of the adjusting movement of the rotor blades via a cylinder or actuator (hose, tire, bellows, etc.) arranged quasi "at rest" on the nacelle and a pressure / tension rod or a pressurized fluid arranged centrally in the rotor shaft and equipped with a mechanical pivot bearing is transmitted to the rotating shaft. Control system according to Claim 1 , characterized in that at least one preferably adjustable pneumatic pressure for a cylinder or actuator is provided for limiting or moving a wind vane, with which the wind energy plant is pivoted in and to limit the maximum values, such as the power from the wind. Control system according to Claim 1 , characterized in that a mast integrated generator or a central drive is provided in the mast. Control system according to Claim 1 , characterized in that at least one pneumatic pressure is provided which acts by means of an actuator or cylinder on the pivoting direction (the pivot drive) of the system about the vertical axis to automatically pivot the gondola at too much torque or speed from the wind. Control system according to Claim 1 , characterized in that is provided for the rotational movement and / or thrust movement of the rotor blades about its longitudinal axis a rotor blade bearing made of a preferably anodized aluminum round tube in plastic plain bearings. Control system according to Claim 1 , characterized in that the mast of the wind turbine operated by the system is supported by generous node stiffening, according to Patentanmaldung DE 10 2012 009 849.9 towards the foundation and similar patent application DE 10 2012 009 850.2 is protected by elastic bearings / decoupling from fatigue. Control system according to Claim 1 , characterized in that are provided for the adjusting movement of the sheet in the rest position or for the at least partial compensation of the centrifugal force return springs or pneumatic, pressurized by the pneumatic system according to the invention springs. Control system according to Claim 1 , characterized in that an inverter is provided which includes a voltage boosting and control electronics (a step-up converter), which preferably consists of 4 time sequentially clocked combinations of one power semiconductor with an inductance.

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