Windmill Blade Pitch Control via Centrifugal Force
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Solution Overview
Problem
Wind power generators face challenges in controlling excessive rotational speed, which can lead to failure and increased costs due to the need for braking mechanisms and controllers, and also struggle with starting performance, especially in low wind conditions.
Innovation Solution
A windmill design with adjustable blade angles using a biasing unit and spindle mechanism that autonomously controls blade angles based on wind speed, eliminating the need for electrical control and allowing for stable power generation even during power failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a brake mechanism and controller are used to control excessive rotation, then excessive rotation can be prevented, but device complexity and cost increase
Solution Approach 1:
The windmill blade automatically adjusts its own pitch angle in response to wind speed changes through aerodynamic forces and centrifugal effects, eliminating the need for external controllers or braking mechanisms. The system serves itself by using the wind power and rotational dynamics to regulate its own operation.
Solution Approach 2:
The patent replaces complex mechanical braking systems with a passive aerodynamic pitch adjustment mechanism that uses wind pressure and centrifugal force to automatically control blade angle, thereby preventing excessive rotation without requiring brakes or electrical controllers.
2Productivity
If gear mechanism and controller are used to improve starting performance, then starting performance is improved, but device complexity and cost increase
Solution Approach 1:
The blade's pitch angle is automatically adjusted by aerodynamic forces and centrifugal effects based on rotational speed, with no external control system required. The mechanism self-regulates to provide optimal starting performance through passive mechanical response.
Solution Approach 2:
The blade pitch angle dynamically changes with rotational speed through the interaction of wind pressure and centrifugal force on the spindle member, allowing the system to automatically adapt to different operating conditions including startup without fixed gear mechanisms.
3Reliability
If blade angle is fixed for high speed rotation, then excessive rotation can be controlled, but starting performance deteriorates
Solution Approach 1:
The blade pitch angle is made dynamic rather than fixed, automatically adjusting with rotational speed through centrifugal and aerodynamic forces. This allows the blade to operate at different angles for starting versus high-speed conditions, resolving the contradiction between startup performance and excessive speed control.
Solution Approach 2:
The operating parameter of blade pitch angle is changed dynamically based on rotational speed conditions. During startup, the blade maintains a larger angle for high torque, while at high speeds, centrifugal force adjusts the angle to reduce torque and prevent excessive rotation.
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 solution provides efficient autonomous speed control, improving starting performance and preventing excessive rotation, while maintaining low operational costs and ensuring stable power generation across varying wind conditions.
Implementation Method 1
the biasing unit biases and holds the blade, which receives the wind power, at a predetermined angle position for initial rotation
Implementation Method 2
the centrifugal force overcomes the pressing force due to the wind power applied to the blade and the biasing force of the biasing unit
Implementation Method 3
receives wind power to be rotated in a constant rotational direction around a predetermined rotation shaft
Data Source
AI summary
Biasing unit, a spindle member, and a link mechanism of a windmill for a wind power generator vary an angle of a blade in a first stage where the angle is made nearly parallel to the wind so that the blade easily rotates in light winds, a second stage where the angle is made nearly perpendicular to the wind so that the blade easily rotates at high speed when the wind speed increases, and a third stage where the blade is pushed back from the state of being nearly perpendicular to the wind to the state of being nearly parallel to the wind so as to prevent the excessive rotation in strong winds, without electrical control being not required. Accordingly this wind power generator has an excellent starting performance and can control the excessive rotation at low cost.