Patent Publication Number: US-2009232635-A1

Title: Independent sensing system for wind turbines

Description:
FIELD OF THE INVENTION 
     The disclosure is directed to rotating device operations such as a wind turbine operation. In particular, the disclosure is directed to rotating device operations requiring the measurement of various parameters. 
     BACKGROUND OF THE INVENTION 
     Recently, wind turbines have received increased attention as environmentally safe and relatively inexpensive alternative energy sources. With this growing interest, considerable efforts have been made to develop wind turbines that are reliable and efficient. 
     Generally, a wind turbine includes a rotor having multiple blades. The rotor is mounted to a housing or nacelle, which is positioned on top of a truss or tubular tower. Utility grade wind turbines (i.e., wind turbines designed to provide electrical power to a utility grid) can have large rotors (e.g., 30 or more meters in length). In addition, the wind turbines are typically mounted on towers that are at least 60 meters in height. Access and/or monitoring to these large wind turbines can be difficult and/or expensive, particularly at wind turbine installations offshore. When the length of the blades on wind turbines is increased, additional parameters are monitored to adjust the blade for maximum efficiency and to reduce blade component costs/weight. Information about particular operational parameters may improve operation and/or maintenance of wind turbines. For example, acceleration of the blades may be measured in a number of directions. The acceleration information may provide information regarding operation, such as noise produced by the blades. In addition, other operational parameters that may be measured include aerodynamic stall, temperatures, forces, and/or mechanical deflection. The parameters can be used to monitor the blade, to increase the energy production, to extend the lifetime of a blade. 
     In the past, measurements of particular operational parameters, including blade conditions and properties have been difficult. As the wind turbines increase in size, longer blades are needed. To efficiently monitor and adjust the blades, measurement must be taken from on and/or within the blades. 
     In addition, wired sensor systems suffer from the drawback that lightning strikes may be conveyed along wires to more sensitive systems causing damage to the wind turbine and wind turbine systems. Fiber optic systems for use in communication to sensors are not easily handled and are expensive. In addition, optical or electrical wires must extend from the rotor to the blade. Inclusion of these wires requires slip rings and increases part costs and maintenance costs. 
     What is needed is a device, method, and system for measuring wind turbine blade parameters and communicating the data so that efficient control and monitoring can be performed that is capable of withstanding the conditions associated with wind turbine operation and includes reduced or eliminated risk in damaging important equipment within the wind turbine during lightning strikes and to increase productivity of the wind turbine. 
     SUMMARY OF THE INVENTION 
     An aspect of the present disclosure includes a wireless sensing device for use in a wind turbine having a sensor capable of measuring one or more parameters for wind turbine operation. The sensing device also includes a transmission device capable of wirelessly transmitting one or more signals corresponding to the one or more measured parameters to a controller. An independent power source is included to power the transmission device and the sensor. 
     Another aspect of the present disclosure includes a wind turbine monitoring system. The system includes a controller configured to operate a wind turbine, a wind turbine component, and a wireless sensing device arranged and disposed with respect to the wind turbine component to sense one or more parameters for wind turbine operation. The wireless sensing device includes a sensor capable of measuring the one or more parameters and a transmission device capable of wirelessly transmitting one or more signals corresponding to the one or more measured parameters to the controller. An independent power source is included to power the transmission device and the sensor. 
     Still another aspect of the present disclosure includes a method for operating a wind turbine. The method includes providing a controller configured to operate a wind turbine, a wind turbine component; and a wireless sensing device arranged and disposed with respect to the wind turbine component to sense one or more parameters for wind turbine operation. The wireless sensing device includes a sensor capable of measuring the one or more parameters for wind turbine operation, a transmission device, and an independent power source for powering the transmission device and sensor. The one or more parameters are measured with the sensor and are transmitted to the controller. The wind turbine is operated with the controller in response to the one or more parameters. 
     Embodiment of the disclosure include a device, system, and method based upon radio frequency, having an independent power supply, allowing for the wireless transmission of measurements taken by a sensor in or on a wind turbine component. The use of an independent power source and wireless transmission of information permits the wireless sensing device to provide information about operational parameters, while preventing or eliminating propagation of lightning strikes, particularly to the blades, to important wind turbine controls or components. 
     One advantage includes a system for monitoring that requires little or no maintenance. 
     In addition, the system is inexpensive and may utilize wireless communication that permits flexibility in the monitoring and operation of the wind turbine. 
     Further, the system provides a method that is capable of taking into account blade parameters in the operation of the wind turbine to provide efficient operation. 
     Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a wind turbine according to an embodiment of the present disclosure. 
         FIG. 2  shows a cutaway view of a nacelle according to an embodiment of the present disclosure. 
         FIG. 3  is a front view of a wind turbine according to an embodiment of the present disclosure. 
         FIG. 4  is a schematic view of a wireless sensing device according to an embodiment of the present disclosure. 
         FIG. 5  shows a cutaway view of a nacelle having a wireless device mounted on the low speed shaft according to an embodiment of the present disclosure. 
     
    
    
     Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in  FIG. 1 , a wind turbine  100  generally comprises a nacelle  102  housing a generator (not shown in  FIG. 1 ). Nacelle  102  is a housing mounted atop a tower  104 , only a portion of which is shown in  FIG. 1 . The height of tower  104  is selected based upon factors and conditions known in the art, and may extend to heights up to 100 meters or more. The wind turbine  100  may be installed on any terrain providing access to areas having desirable wind conditions. The terrain may vary greatly and may include, but is not limited to, mountainous terrain or offshore locations. Wind turbine  100  also comprises a rotor  106  that includes one or more rotor blades  108  attached to a rotating hub  110 . Although wind turbine  100  illustrated in  FIG. 1  includes three rotor blades  108 , there are no specific limits on the number of rotor blades  108  required by the present disclosure. 
     As shown in  FIG. 2 , various components are housed in nacelle  102  atop tower  104  of wind turbine  100 . For example, a variable blade pitch drive  114  may control the pitch of blades  108  (not shown in  FIG. 2 ) that drive hub  110  as a result of wind. Hub  110  may be configured to receive three blades  108 , but other configurations may utilize any number of blades. In some configurations, the pitches of blades  108  are individually controlled by blade pitch drive  114 . Hub  110  and blades  108  together comprise wind turbine rotor  106 . The pitch gear assembly  115  is a ring and pinion gear arrangement driven by blade pitch drive  114 , having a circular pinion assembly  135  engaging a ring assembly  137 . The ring assembly  137  is a single gear with multiple gear teeth arranged in a substantially arcuate arrangement and connected to the blade  108  in a manner that permits adjustment of the pitch of blades  108 . The teeth of the pinion assembly  135  mesh with the teeth of the ring assembly  137  and translate the rotational motion provided by the pitch drive  114  through the pinion assembly  135  into the rotational motion of the ring portion  137  that corresponds to pitch angles for the blade  108 . The pitch angle adjusts the transmission of force from the wind to the blade  108  and rotor  106 , allowing control of rotational speed and torque. 
     The drive train of the wind turbine  100  includes a main rotor shaft  116  (also referred to as a “low speed shaft”) connected to hub  110  via main bearing  130  and (in some configurations), at an opposite end of shaft  116  to a gear box  118 . Gear box  118 , in some configurations, utilizes a dual path geometry to drive an enclosed high speed shaft. In other configurations, main rotor shaft  116  is coupled directly to generator  120 . The high speed shaft (not shown in  FIG. 2 ) is used to drive generator  120 , which is mounted on main frame  132 . In some configurations, rotor torque is transmitted via coupling  122 . Generator  120  may be of any suitable type, for example and without limitation, a wound rotor induction generator or a direct drive permanent magnet generator. In one embodiment, the variable speed system comprises a wind turbine generator with power/torque capability, which is coupled to and supplies generated power to a grid. 
     Yaw drive  124  and yaw deck  126  provide a yaw orientation system for wind turbine  100  to rotate the wind turbine to a position that faces the wind. Meterological boom  128  provides information for a turbine control system, including wind direction and/or wind speed. In some configurations, the yaw system is mounted on a flange provided atop tower  104 . The configuration shown in  FIG. 2  is merely exemplary. The present disclosure is not limited to the particular configuration shown in  FIG. 2 . For example, the wind turbine  100  of the present disclosure may include alternate configurations of generators  120  and gear box  118 , including direct drive systems and systems that eliminate the use of gear box  118 . 
     As shown in  FIGS. 1 and 2 , the wind turbine  100  includes a number of rotating devices and components. As the size and accessibility of the individual components is limited, the monitoring and/or measuring of operational parameters may be accomplished wirelessly with wireless sensing devices  300  (see e.g.,  FIG. 3 ) according to embodiments of the present disclosure. 
       FIG. 3  shows a front view of wind turbine system according to an embodiment of the disclosure. The wind turbine  100  includes a plurality of blades  108  that rotate about hub  104 . A wireless sensing device  300  is mounted onto a blade  108  and measures an operational parameter. “Operational parameters”, “parameters” and grammatical variations thereof, as used herein, include parameters usable for operation of the wind turbine and wind farm/wind plant management systems. Suitable operational parameters include, but are not limited to, acceleration, vibration, noise, temperature, pressure, stress, deflection and combinations thereof. The components onto into or into which the wireless sensing device  300  may be mounted is not limited to wind turbine blades  108 , but may include any rotating device including the low speed shaft  116 , the hub  104 , the components of gear box  118 , the generator  120  or any other rotating components. The wireless sensing device  300  transmits wireless signals  305  to a controller  303 . The controller  303  is a device capable of receiving wireless signals  305  and providing operational instructions to the wind turbine  100  in response to the wireless signals  305 . The controller  303  may be any conventional controlling device known for use with wind turbine devices and may include wired or wireless connections to the wind turbine  100  for purposes of operation and control. For example, the controller  303  may receive a wireless signal  305  from the wireless sensing device corresponding to a parameter such as noise, which exceeds a predetermined limit for noise. In response, the controller  303  may send a signal or instructions to the wind turbine local controls to adjust the pitch angle of the blades  108 , torque settings at the generator  120  or any other operational parameters suitable for reducing noise. 
     As shown in  FIG. 4 , the wireless sensing device  300  includes an independent power source  403  that provides electrical power for sensing and/or transmitting parameter information. The independent power source  403  is a power source that is substantially independent of electrical connections to external components. For example, the independent power source  403  may include mechanical to electrical power converter, batteries, photovoltaic cells, other power sources suitable for powering the wireless sensing device  300  or combinations thereof. One embodiment of the present disclosure includes a mechanical to electrical converter having a linear motion energy converter capable of converting linear/vibratory motion to electrical current. In one embodiment, one or more batteries may be present as an accumulator and/or backup power to the mechanical to electrical power converter to supplement and/or collect power produced by the mechanical to electrical power converter. The independent power source  403  is in electrical communication with the transmitting device  405 . The transmitting device  405  is a device capable of transmitting or transmitting and receiving wireless signals. While not so limited, the wireless signals  305  may include any electromagnetic energy capable of transmitting information. For example, the wireless signals  305  may include a radio frequency transmitter or transceiver or an infrared transmitter or transceiver. In addition, wireless signals  305  may include radio frequency (RF) wireless area networks (WLAN), including any wireless protocols known for wireless transmission. In addition, a sensor  407  is also in communication with the transmitting device  405 , wherein the sensor  407  is a device capable of sensing or measuring one or more operational parameters. For example, the sensor  407  may measure acceleration, vibration, noise, temperature, pressure, stress, deflection and combinations thereof. Example of suitable sensors  407  include, but are not limited to piezoelectric sensors, accelerometers, thermometers, thermocouples, thermistors, optical sensors, microphones, potentiometer/resistors, strain gauges, pressure sensors or any other sensors suitable for measuring parameters such as acceleration, vibration, noise, temperature, deflection and stress. For example, the wireless sensing device  300  may be a unitary component, such as individual subcomponents mounted on a printed circuit board, or may be individual components wired or soldered together. 
       FIG. 5  includes an arrangement within nacelle  102  substantially identical to the arrangement shown and described in  FIG. 2 . However, as shown in  FIG. 5 , a wireless sensing device  300  is disposed on low speed shaft  116 . The wireless sensing device  300  may be configured to measure the forces and/or deflection on the shaft  116 . The mounting of the wireless sensing device  300  on the rotating shaft  116  permits monitoring of the conditions of the low speed shaft  116  without the need of wired communication connections or wired power connection. In addition, the rotation of shaft  116  permits the power source  403 , which may be a mechanical to electrical power converter, to generate electricity and power the sensor  407  and the transmitting device  405 . 
     While the above has been described with respect to wireless sensing device installations on blades  108  and low speed shaft  116 , the wireless sensing device  300  may be mounted on any other component within the wind turbine  100  that experiences motion and has a need for component monitoring or monitoring of the conditions surrounding the component. In particular components that are difficult to service, such as large components, components having limited access or components that have motion that makes wiring difficult or impossible are particularly suitable for use with the wireless sensing device  300 . 
     While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.