Low-Speed Multiblade Wind Turbine With Self-Starting Torque
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Solution Overview
Problem
Wind turbines in regions with low-to-medium wind speeds face challenges in starting due to insufficient torque, as the lift-to-drag ratio is low and blade angle is high, making it difficult to overcome inertia and static friction.
Innovation Solution
A wind turbine design with a rotor hub and blades having specific chord length and angle of twist distributions, optimized using blade element momentum theory, to enhance starting torque and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If small wind turbine models are utilized in regions with low-to-medium wind speeds, then the turbine can operate in these conditions, but the starting torque is insufficient to overcome inertia and static friction
Solution Approach 1:
The blade is divided into multiple sections along its length, with each section having locally optimized chord length and angle of twist values. This local quality variation allows the blade to generate higher starting torque near the hub while maintaining aerodynamic efficiency at the tip, resolving the contradiction between adaptability to low wind speeds and sufficient starting torque.
Solution Approach 2:
The invention optimizes specific geometric parameters (chord length and angle of twist) of the blade sections to maximize starting torque. By carefully selecting and varying these parameters along the blade length, the design achieves both the ability to operate in low-to-medium wind speed regions and sufficient starting torque to overcome inertia and static friction.
2Force
If the blade angle is increased to improve starting torque, then more torque can be generated, but the lift-to-drag ratio decreases, reducing overall efficiency
Solution Approach 1:
Different sections of the blade have different angle of twist values, creating local quality variation. The root sections have higher angles to maximize starting torque, while outer sections have lower angles to maintain optimal lift-to-drag ratio. This resolves the contradiction between generating sufficient starting torque and minimizing energy loss during operation.
Solution Approach 2:
The blade is segmented into multiple sections along its length, with each section independently optimized for its specific functional requirements. This segmentation allows the inner sections to focus on torque generation while outer sections focus on efficient energy capture, resolving the contradiction between starting torque and operational efficiency.
3Reliability
If the chord length of blade sections is optimized for high starting torque, then self-starting capability is achieved, but the blade complexity increases
Solution Approach 1:
The blade employs local quality variation with specific chord length and angle of twist values at different sections. This approach achieves self-starting capability through optimized local characteristics without requiring complex overall blade geometry or additional mechanical components, thus minimizing device complexity while ensuring reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves a starting torque greater than 25 N-m, enabling self-starting in regions with average wind speeds of less than 5 m/s, improving energy capture and reducing the impact of seasonal wind variations.
Implementation Method 1
A wind turbine converts the kinetic energy of the wind into mechanical energy which in turn is converted into electrical energy using a generator
Implementation Method 2
A wind turbine converts the kinetic energy of the wind into mechanical energy which in turn is converted into electrical energy using a generator
Data Source
AI summary
A wind turbine for a region with an average wind speed of less than 5 m/s includes a rotor comprising a rotor hub and multiple blades connected to the rotor hub. The rotor is configured for rotation with a starting torque and a torque-magnitude-profile-over-time. Each blade has multiple sections distributed between a blade root and a blade tip, and each section has a chord length and an angle of twist. The chord length is a first non-dimensional value from 0 to 1 and the angle of twist is specified in radian. The first and second non-dimensional values are convertible to dimensional values in meters by multiplying the first non-dimensional values by a maximum chord length.