# US 9,753,050 B2 · Wind turbine component having an optical fibre wind sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,753,050 B2 - Document ID: US9753050B2 - Status: Granted - Kind: B2 - Application number: 14/763,374 - Filed: 2013-02-15 - Published: 2015-12-17 - Granted: 2017-09-05 - Earliest claimed: 2013-02-15 - Assignees: Vestas Wind Systems A/S - Applicants: Vestas Wind Systems A/S - Inventors: Chee Kang Lim; Jia Liang Ang - Web page: https://patentgrep.com/patent/US9753050B2 ## CPC - G01P 5/02: by measuring forces exerted by the fluid on solid bodies, e.g. anemometer - G01D 5/268: {using optical fibres (G01D5/28 - G01D5/38 take precedence)} - G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G}) - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR ## Abstract The application relates to a wind turbine component having an optical fiber sensor arranged to detect wind speed over the surface of the component. In one embodiment, the optical fiber sensor has a light loss portion that allows some of the light transmitted through the optical fiber to escape. The amount that the optical fiber bends in the air flow across the surface causes the effective surface area of the light loss portion to increase or decrease. With increased or decreased surface area of the light loss portion, more or less light is lost from the fiber. The intensity of the light transmitted in the fiber can therefore be used as a measure of the amount of bending, and therefore as a measure of the air flow's speed. In other embodiments, the optical fiber includes optical gratings, such as Fiber Bragg Gratings. ## Claims ### Claim 1 A wind turbine component comprising: an optical fibre extending from the wind turbine component surface into an air flow region adjacent the wind turbine component surface, that includes a first sensing portion extending from the surface of the wind turbine component, a terminating loop section connected to the first sensing portion, and a second portion connected to the terminating loop section and returning to the surface of the wind turbine component, wherein the optical fibre doubles back on itself via the terminating loop section, such that the optical fibre first and second sensing portions bend as a result of a force exerted by the air flow; a light source for inputting a light signal into at least one end of the optical fibre, the light signal having an optical characteristic that is changed by its transmission through the optical fibre and by the amount the optical fibre is bending; a photo detector for receiving a light signal from the sensing portion of the optical fibre; and a controller coupled to the photo detector to determine the wind speed from the optical characteristic of the received light signal. ### Claim 2 (depends on 1) The wind turbine component of claim 1, wherein the bending of the optical fibre sensing portion is constrained to a first axial direction. ### Claim 3 (depends on 1) The wind turbine component of claim 1, wherein the bending of the optical fibre sensing portion has a range defined by a maximum and a minimum value, and wherein a no wind situation corresponds to one of the minimum value and a middle value. ### Claim 4 (depends on 1) The wind turbine component of claim 1, wherein first ends of the first and second sensing portions are fixed at the surface of the wind turbine component surface, and second ends of the first and second sensing portions are free to move in the air flow. ### Claim 5 (depends on 1) The wind turbine component of claim 1, wherein the optical characteristic is the intensity of the received light, and wherein the surface of the optical fibre first sensing portion and second sending portion each has one or more light loss portions arranged to allow light to escape from the fibre, the amount of light escaping from the fibre depending on the amount of bending of the light loss portion. ### Claim 6 (depends on 5) The wind turbine component of claim 5, wherein the light loss portions comprise cut-outs in the coating of the optical fibre. ### Claim 7 (depends on 6) The wind turbine component of the claim 6, wherein the cut outs are serrations. ### Claim 8 (depends on 1) The wind turbine component of claim 1, wherein the first sensing portion and the second sending portion are attached to a resilient support member also extending into the air flow. ### Claim 9 (depends on 8) The wind turbine component of claim 8, wherein the optical fibre first sensing portion and second sensing portion each has one or more gratings, the spacing of the gratings changing due to bending of the sensing portion. ### Claim 10 (depends on 1) A stall sensor for a wind turbine blade comprising the wind turbine component of claim 1. ### Claim 11 (depends on 1) A stagnation point sensor for a wind turbine blade comprising the wind turbine component of claim 1. ### Claim 12 A method of detecting the speed of the air flow across a wind turbine component, the method comprising: inputting a light signal into a first sensing portion of an optical fibre extending from the wind turbine component surface into an air flow region adjacent the wind turbine component surface, that includes the first sensing portion extending from the surface of the wind turbine component, a terminating loop section connected to the first sensing portion, and a second portion connected to the terminating loop section and returning to the surface of the wind turbine component, wherein the optical fibre doubles back on itself via the terminating loop section, such that the optical fibre first and second sensing portions bend as a result of a force exerted by the air flow, and the light signal having an optical characteristic that is changed by its transmission through the optical fibre and by the amount the optical fibre is bending; receiving a light signal from the second sensing portion of the optical fibre; and determining the speed of the air flow from the optical characteristic of the received light signal. ### Claim 13 (depends on 12) The method of claim 12, wherein the optical characteristic is one of the intensity of the light and the frequency of the light received from the optical fibre. ### Claim 14 (depends on 1) The wind turbine component of claim 1, wherein the first sensing portion of the optical fibre is disposed on a first side of a resilient support member and wherein the second sensing portion is disposed on an opposing second side of the resilient support member, wherein the first sensing portion and the second sensing portion are maintained under tension when in a neutral position, and wherein the first and second sensing portions experience different amounts of tension when the first and second sensing portions bend.