Generator module for harvesting energy from wind turbine blade rotation for internal blade fault detection and monitoring

Abstract

A generator module for harvesting energy from wind turbine blade rotation is disclosed. The module is installed inside a turbine blade at a selectable distance from the hub and comprises a generator, a gearbox for optimizing power conversion, and a mounting structure. An oscillating mass interacts with an adjustable spring mechanism, which compensates for centrifugal and gravitational forces based on the installation position. Rotational amplitude limits constrain the oscillating mass, ensuring controlled oscillations that drive the generator. A sensor system, including an accelerometer, detects rotational speed, and a controller dynamically adjusts spring stiffness via an actuator mechanism to maintain optimal energy harvesting efficiency. The system further integrates a fault detection and monitoring device powered by the generator module, comprising sensors to detect blade damage and a communication module for real-time data transmission. The invention enables autonomous monitoring and predictive maintenance without external power sources, improving turbine reliability and operational efficiency.

Description

[0001] Generator module for harvesting energy from wind turbine blade rotation for internal blade fault detection and monitoring

[0002] Field Of The Invention

[0003]

[0001] The invention relates generally to wind turbine technology, particularly to generator modules adapted for harvesting rotational energy from wind turbine blades. Specifically, the invention pertains to a generator module configured to convert mechanical motion resulting from the rotation of wind turbine blades into electrical energy, intended to power internal sensors and monitoring systems designed for continuous structural health monitoring and detection of blade damage, defects, or operational irregularities.

[0004] Background Of The Invention

[0005]

[0002] Wind turbines represent a widely used solution for generating renewable energy. The turbine blades, typically constructed from glass fiber reinforced composites, have progressively grown larger to increase power generation efficiency. However, the structural integrity of these blades can be compromised over time due to operational stresses, environmental conditions, manufacturing defects, or external damage events such as lightning strikes or collisions.

[0006]

[0003] Common defects arising in wind turbine blades include cracks, delamination, and other structural anomalies that adversely affect performance, safety, and operational lifespan. Early detection and monitoring of such defects are crucial for preventing catastrophic blade failure, reducing downtime, and lowering maintenance costs. Conventional inspection approaches primarily rely on visual inspections using drones to identify defects externally. Increasingly, internal blade inspections carried out by human inspectors or specialized robotic devices have become popular as supplementary methods.

[0007]

[0004] Nevertheless, even after identifying blade damage, wind turbine operators face difficult operational choices. If identified damage is deemed critical, the affected wind turbine must be stopped, and costly repairs arranged. Repair teams may not always be readily available, potentially leading to prolonged turbine downtime and significant economic losses due to reduced energy production.

[0005] Therefore, there is a clear and urgent need for solutions that enable continuous monitoring of known or suspected blade defects internally and remotely, facilitating efficient maintenance planning, reducing downtime, and optimizing turbine operations. Such internal monitoring devices ideally should operate independently without external power sources or extensive wiring, to reduce installation complexity, cost, and weight.

[0008]

[0006] Although existing solutions already propose internal blade monitoring systems and energy harvesting methods, such solutions typically face limitations regarding the ability to continuously generate sufficient and stable power from blade rotation. Furthermore, known generator modules typically employ fixed weighted-mass arrangements optimized for a limited range of operating conditions. These known systems do not adequately address the variability of centrifugal forces and gravitational forces that vary significantly depending on the blade radius location and operational rotation speed.

[0009]

[0007] There is known a wind turbine blade health status monitoring device disclosed in [1], comprising a monitoring cabinet installed externally atop the wind turbine nacelle. This device may utilize a thermal imaging camera, laser rangefinder, digital inclinometer, vibration, strain, temperature and acceleration sensors to evaluate blade health status from an external position. However, due to its external mounting, the device primarily detects external blade surface conditions, limiting its ability to identify internal blade defects such as cracks or delaminations. Additionally, this known system does not provide or suggest an internal, autonomously powered energy harvesting mechanism, nor does it employ adjustable spring-based mechanisms optimized for gravitational and centrifugal forces within the rotating blade structure.

[0010]

[0008] There is known a rotational energy harvesting module [2], adapted for installation inside wind turbine blades, comprising a generator module configured to convert mechanical energy resulting from the rotation of wind turbine blades into electrical energy. The known device includes a weighted mass and is installed at the blade root area or hub region, producing a regulated DC output to power internal sensor nodes, thereby eliminating the need for batteries or external wiring within the blades.

[0009] There are also known rotational or vibration -based energy harvesting systems disclosed in [3] and [4], which utilize inertial masses, electromagnetic induction, or piezoelectric elements to generate electrical energy from motion. However, such systems are typically optimized for specific mounting locations or operating conditions and do not account for the varying dynamic behavior along the length of a wind turbine blade. Consequently, known solutions fail to consistently achieve optimal energy harvesting efficiency and reliability, especially when installed at varying distances from the turbine hub.

[0011] Brief Summary Of The Invention

[0012]

[0010] The goal of the invention is to overcome the drawbacks of the prior art and provide a generator module for harvesting rotational energy from wind turbine blades, adapted specifically for continuous internal blade monitoring. The generator module is designed to reliably supply power to internal sensors without external power sources, cables, or frequent maintenance, thereby enabling effective internal monitoring of blade structural health, early detection of internal defects, and reduced turbine downtime.

[0013]

[0011] This goal is achieved by a generator module comprising a generator, a gearbox operatively coupled to the generator, an adjustable spring mechanism, and a mounting structure adapted to secure the module within the blade. The adjustable spring mechanism is configured to compensate for gravitational and centrifugal forces experienced by the module, depending on its installation distance from the wind turbine hub and operational rotational frequency. In some embodiments, an actuator mechanism continuously and dynamically adjusts the spring stiffness based on realtime sensor data to maintain optimal energy harvesting conditions. This feature ensures that the generator module provides optimized energy harvesting efficiency by dynamically adjusting the stiffness of the spring to match the operational conditions at the installation location.

[0014]

[0012] Preferably, the generator module further includes a sensor system configured to measure the rotational speed of the turbine blade, a controller to determine optimal spring stiffness adjustments based on sensor measurements, and an actuator mechanism that automatically adjusts spring stiffness. This allows the module tocontinuously maintain maximum energy harvesting efficiency throughout variable operational conditions.

[0015]

[0013] In a preferred embodiment, the generator module powers a wind turbine fault-detection device that includes sensors such as a camera, humidity sensor, microphone, vibration, strain, temperature and lightning-detection sensor. The fault detection and monitoring device further includes a wireless transmitter configured to send monitoring data to a remote monitoring system, enabling continuous, autonomous internal monitoring of blade conditions without reliance on external power sources or extensive wiring.

[0016]

[0014] As a result, the invention ensures reliable and continuous internal monitoring of wind turbine blades, providing significant operational advantages by reducing maintenance downtime, improving blade reliability, and enabling timely interventions upon detecting structural damage.

[0017] Brief Description Of The Drawings

[0018]

[0015] Fig. 1 shows a perspective view of the monitoring device according to the invention installed within a wind turbine blade, illustrating the mounting structure including the case, camera, antenna, and fixing components adapted for internal blade attachment.

[0019] Fig. 2 - a schematic representation of multiple possible installation positions of the claimed device within the blade.

[0020] Fig. 3 - a schematic representation of the internal mechanical components of the generator module according to the invention, including the adjustable spring mechanism, generator with gearbox, movable mass, rotational amplitude limits, and dampeners for optimal energy harvesting.

[0021] Fig. 4 - a schematic representation of the mechanical components of the generator module comprising an accelerometer, a controller, an actuator mechanism and a spring mechanism.

[0022] Fig. 5 - a simplified schematic electrical diagram illustrating the electrical components of the invention, including a generator, bridge rectifier, load optimizer, battery or capacitor storage, voltage stabilizer, and connected load [sensors or wireless transmission devices).Detailed Description Of The Invention

[0023]

[0016] The claimed generator module [1] for harvesting energy from wind turbine blade

[0010] rotation is adapted to be installed inside a wind turbine blade

[0010] at a selectable distance from a turbine hub

[0012] - Fig. 1-2. The generator module [1] comprises a generator

[0020] configured to convert mechanical motion into electrical energy; a gearbox

[0021] operatively coupled to the generator

[0020] for optimizing power conversion efficiency; and a mounting structure [5] adapted to secure the generator module [1] within the wind turbine blade (10).

[0024]

[0017] The mounting structure (5) may comprise a support framework configured to securely hold the generator module (1) inside the wind turbine blade (10) - Fig. 1. The structure may include brackets (5) or other fixation elements that attach to the inner surface of the blade (10), ensuring mechanical stability under operational conditions. Various adhesion techniques, reinforcement layers (5a), or mechanical fasteners (such as e.g. bolts and nuts (6a), straps (6b)) may be employed to enhance the durability and reliability of the installation. In some embodiments, UV-curable adhesives or composite reinforcements may be used to improve structural integrity. The system is designed to withstand dynamic loads and vibrations while maintaining stable positioning of the generator module (1).

[0025]

[0018] The generator module (1) further comprises: an oscillating mass (22); an adjustable spring mechanism (23) operatively connected to the oscillating mass (22) and having an adjustable spring stiffness configured to compensate for centrifugal and gravitational forces acting on the generator module (1) based on its installation distance from the turbine hub (12) (Fig. 2-3). The oscillating mass (22) will oscillate in response to centrifugal and gravitational forces, transmitting motion through a gearbox to rotate the generator (20) alternately in opposite directions.

[0026]

[0019] The generator module (1) is further provided with rotational amplitude limits (25) configured as mechanical stops to constrain the movement of the oscillating mass (22) within a predefined range, ensuring controlled oscillatory motion.

[0027]

[0020] The adjustable spring mechanism (23) is designed to apply a restoring force to the oscillating mass (22), enabling controlled oscillations within the constraintsdefined by the rotational amplitude limits (25) to generate mechanical energy for conversion by the generator (20) - Fig. 3.

[0028]

[0021] According to an embodiment, the spring mechanism (23) may comprise a torsional or linear spring (23a), adjustable based on the calculated centrifugal force acting on the generator module (1) at the installed distance from the turbine hub (12). According to one embodiment, the spring mechanism (23) may have an adjustable spring end (23b) configured to modify the attachment position of the spring (23a), thereby varying the restoring force acting on the oscillating mass (22).

[0029]

[0022] During wind turbine blade (10) rotation, the blade (10) experiences varying centrifugal and gravitational forces depending on its angular position relative to vertical. When the blade (10) points downward, gravitational force adds to the centrifugal force, maximizing total acceleration, whereas in the upward position, gravitational force subtracts, reducing net acceleration. The spring mechanism (23) can be adjustable manually or dynamically using an actuator mechanism (31) to compensate for centrifugal and gravitational forces acting on the oscillating mass (22).

[0030]

[0023] According to yet another embodiment, the generator module (1) may further comprise: accelerometer (3) configured to measure the rotational speed of the wind turbine blade (10); a controller (30) configured to process the measurements from the accelerometer (3) and determine required adjustments to the spring (23a) stiffness based on the balance between gravitational and centrifugal forces acting at the installation distance from the turbine hub (12); and an actuator mechanism (31) operatively connected to the spring mechanism (23) for automatically adjusting the spring (23a) stiffness based on commands from the controller (30) - Fig. 4. The actuator mechanism (31) may include a servo-driven, electromagnetic, piezoelectric, or fluidic actuator, which is operatively connected to the spring mechanism (23). Upon receiving a control signal from the controller (30), the actuator mechanism (31) modifies the spring mechanism (23) stiffness by adjusting its preload, anchor position, or compression force. The system continuously monitors the rotational speed of the wind turbine blade (10) and may dynamically adjust the stiffness of the spring mechanism (23) to compensate for varying centrifugal and gravitational forces, ensuring optimal energy harvesting conditions. According to an embodiment, the controller (30) receives real-time rotational speed data from the accelerometer (3) andcalculates force variations using a predefined relationship. The centrifugal force ( ) is calculated as F=mrω2, where m is the mass of the oscillating mass (22), r is the installation distance from the turbine hub (12), and ω is the rotational speed. Based on these calculations, the controller (30) determines the required spring stiffness adjustments to maintain optimal resonance conditions. The controller (30) processes this force calculation in real time to determine the necessary stiffness adjustments for the spring mechanism (23) and transmits control signals to the actuator mechanism (31), which modifies the spring (23a) stiffness by adjusting its preload, attachment position, or tensioning force. This real-time adjustment ensures that the oscillating mass (22) operates under optimal resonance conditions for efficient energy harvesting.

[0031]

[0024] The generator module (1) may further comprise a lever arm (24) operatively connected to the oscillating mass (22) and configured to transmit mechanical motion to the generator (20).

[0032]

[0025] According to yet another embodiment, the generator module (1) may further comprise dampening elements (26) mechanically positioned to interact with the oscillating mass (22), limiting its movement within the defined range set by the rotational amplitude limits (25).

[0033]

[0026] To achieve maximum efficiency, generator module (1) is tuned by adjusting the spring (23a) stiffness so that the natural oscillation frequency of the oscillating mass (22) matches the nominal rotational frequency of the turbine blade (10). This resonance effect maximizes energy transfer to the generator (20), ensuring efficient conversion of mechanical energy into electrical energy. The spring (23a) stiffness k is selected based on the mass (m) and desired angular frequency (to) according to the relationship k=mω2, where ω represents the nominal rotational frequency of the turbine blade (10). Adjusting the spring (23a) stiffness ensures the oscillating mass (22) optimally, efficiently converting the mechanical energy induced by blade (10) rotation into electrical energy via the gearbox (21) connected generator (20).

[0034]

[0027] In yet another embodiment, the actuator system (31) maybe designed to be selfcalibrating, periodically adjusting the baseline stiffness of the spring mechanism (23) to account for long-term variations in operating conditions. Additionally, the actuator system (31) may be configured to dynamically adjust the stiffness of the spring mechanism (23) in response to real-time operational conditions. The actuator system(31) is operatively connected to a sensor system (40), which includes an accelerometer (3) and / or other suitable sensors configured to measure rotational speed, oscillation amplitude, and environmental factors affecting the generator module (1). The controller (30) processes these sensor measurements and determines the required stiffness adjustments to compensate for variations in centrifugal and gravitational forces acting on the oscillating mass (22) at different positions within the wind turbine blade (10). The actuator mechanism (31) modifies the stiffness of the spring mechanism (23) by adjusting its preload, attachment position, or tensioning force, ensuring optimal resonance tuning and energy harvesting efficiency.

[0035]

[0028] Fig. 5 shows a schematic electrical diagram of the power supply by the generator module (1). The generator (20) produces alternating current (AC), which is converted into direct current (DC) by a bridge rectifier (51). The DC output from the rectifier (51) is processed through a load optimizer (52) circuit, ensuring optimal electrical performance according to the generator's (20) rotational characteristics. The optimized output is stored in a battery or capacitor (53), which provides continuous and stable power. A voltage stabilizer (54) further conditions this stored energy to deliver consistent voltage and current output, supplying power reliably to the connected load (55) comprising e.g. monitoring sensors (e.g. as a camera, humidity sensor, microphone, lightning-detection sensor, acoustic or ultrasonic sensors, vibration, strain, and temperature sensors), communication modules, and associated electronic components within the wind turbine blade (10).

[0036]

[0029] The invention also provides for a wind turbine blade fault detection and monitoring device, comprising: the generator module (1) as set forth above; at least one sensor system (40) configured to detect operational parameters indicative of blade damage (e.g. cracks, delamination, material fatigue, erosion, lightning strike damage, structural deformations, imbalance, and abnormal vibrations); and a communication module (4) operatively connected to the sensor system (40), configured to transmit sensor data to a remote monitoring system (32). The generator module (1) is electrically connected to the sensor system (40) and communication module (4), supplying continuous power for monitoring and data transmission without external power sources. The sensor system (40) may comprise a camera, a microphone, a humidity sensor, a lightning detection sensor, an acoustic sensor, an ultrasonic sensor,a vibration sensor, a strain sensor, a temperature sensor, and any other sensor configured to detect structural integrity parameters or operational performance metrics of the wind turbine blade (10).

[0037]

[0030] According to the preferred embodiment, the communication module (4) comprises a wireless transmitter (33) configured to send real-time blade condition data, including structural integrity parameters and / or operational performance metrics, to a remote monitoring system (32).

[0038]

[0031] The claimed system can not only harvest rotational energy from the wind turbine blade and provide continuous power to onboard monitoring systems, but also detect early signs of mechanical fatigue by analyzing oscillation patterns. By continuously processing real-time sensor data, the system can identify anomalies indicative of structural degradation, imbalance, or excessive vibration. Furthermore, it can transmit maintenance alerts, enabling timely interventions to prevent critical failures, reduce downtime, and optimize turbine performance.

[0039] References

[0040] [1] CN218235351U.

[0041] [2] VolPower Datasheet, Onvol, Inc. - https: / / onvol.com / datasheet / voldrive-datasheet /

[0042]

[0043] datasheet and https: / / onvol.com / datasheet / volpower-datasheet /

[0044] [3] US 2011 / 193350 Al.

[0045] [4] US 6304176 Bl.

Claims

Claims1. A generator module (1) for harvesting energy from rotation of a wind turbine blade (10), adapted to be installed inside a wind turbine blade (10) at a selectable distance from a turbine hub (12), the generator module (1) comprising:a generator (20) configured to convert mechanical motion into electrical energy; a mounting structure (5) adapted to secure the generator module (1) within the wind turbine blade (10); an oscillating mass (22); and a spring mechanism (23) operatively connected to the oscillating mass (22), wherein the spring mechanism (23) is designed to apply a restoring force to the oscillating mass (22) enabling oscillations to generate mechanical energy for conversion by the generator (20); characterized in that the generator module (1) further comprises: a gearbox (21) operatively coupled to the generator (20) for optimizing power conversion efficiency; the spring mechanism (23) is an adjustable spring mechanism having an adjustable spring stiffness configured to compensate for centrifugal and gravitational forces acting on the generator module (1) based on its installation distance from the turbine hub (12); and rotational amplitude limits (25) configured as mechanical stops to constrain movement of the oscillating mass (22) within a predefined range, ensuring controlled oscillatory motion, wherein the adjustable spring mechanism (23) is configured to apply the restoring force such that controlled oscillations occur within the constraints defined by the rotational amplitude limits (25).

2. The generator module (1) according to claim 1, wherein the spring mechanism (23) comprises a torsional or linear spring (23a), adjustable based on the calculated centrifugal force acting on the generator module (1) at the installed distance from the turbine hub (12).

3. The generator module according to claim 1 or 2, further comprising: accelerometer (3) configured to measure the rotational speed of the wind turbine blade (10); a controller (30) configured to process the measurements from the accelerometer (3) and determine required adjustments to the spring (23a) stiffness based on the balance between gravitational and centrifugal forces acting at the installation distance from theturbine hub (12); and an actuator mechanism (31) operatively connected to the spring mechanism (23) for automatically adjusting the spring (23a) stiffness based on commands from the controller (30).

4. The generator module (1) according to any proceeding claims, further comprising a lever arm (24) operatively connected to the oscillating mass (22) and configured to transmit mechanical motion to the generator (20).

5. The generator module (1) according to any proceeding claims, further comprising dampening elements (26) mechanically positioned to interact with the oscillating mass (22), limiting its movement within the defined range set by the rotational amplitude limits (25).

6. The generator module (1) according to claim 3, wherein the actuator mechanism (31) is configured to continuously and dynamically or periodically adjust the spring (23a) stiffness during operation in response to control signals from the controller (30), the controller (30) being configured to: (i) receive real-time rotational speed data from the accelerometer (3); (ii) calculate variations in centrifugal and gravitational forces acting on the oscillating mass (22) using a predefined relationship, wherein the centrifugal force (F) is determined as F=mrω2, where m is the mass of the oscillating mass (22), r is the installation distance from the turbine hub (12), and ω is the rotational speed; and (iii) determine and transmit corresponding stiffness adjustment commands to the actuator mechanism (31) to maintain optimal oscillation conditions for energy harvesting.

7. A wind turbine blade fault detection and monitoring device, comprising: the generator module (1) according to any of claims 1–6; at least one sensor system (40) configured to detect operational parameters indicative of blade damage; and a communication module (4) operatively connected to the sensor system (40), configured to transmit sensor data to a remote monitoring system (32); wherein the generator module (1) is electrically connected to the sensor system (40) andcommunication module (4), supplying continuous power for monitoring and data transmission without external power sources.

8. The monitoring device according to claim 7, wherein the at least one sensor system (40) comprises one or more of: a camera, a microphone, a humidity sensor, a lightning detection sensor, an acoustic sensor, a vibration sensor, a strain sensor, a temperature sensor, and an ultrasonic sensor.

9. The monitoring device according to claim 7 or 8, wherein the communication module (4) comprises a wireless transmitter (33) configured to send real-time blade condition data, including structural integrity parameters and / or operational performance metrics, to a remote monitoring system (32).

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