Variable Moment Flywheel for Wind Turbine Load Smoothing
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Solution Overview
Problem
Wind turbines face challenges in managing fluctuating wind energy, leading to inefficiencies and increased structural loads due to fixed speed systems, and complexity in variable speed systems, as well as issues with angular velocity in 'lift type' vertical axis turbines.
Innovation Solution
A flywheel apparatus with a bowl-shaped container spinning on a vertical axis, divided by radially oriented walls, uses a fluid or small particles to increase moment of inertia and store energy, regulating angular velocity by varying the shape of the bowl and shelves to absorb and release energy in response to wind gusts and lulls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed speed wind turbine generator system is used, then the mechanical structure can be simpler, but the structural loads increase due to drive train torque fluctuations from wind speed variations
Solution Approach 1:
The patent applies the dynamics principle by making the moment of inertia of the flywheel variable rather than fixed. The flywheel's mass distribution changes dynamically in response to wind speed variations, allowing the system to adapt to fluctuating wind conditions. This dynamic adjustment reduces torque fluctuations and structural loads while maintaining a relatively simple mechanical structure without requiring complex variable speed control systems.
2Strength
If a variable speed wind turbine generator system is used, then the structural loads are reduced, but the device complexity increases due to electronic power converters and control systems
Solution Approach 1:
The patent replaces complex electronic control systems and power converters with a purely mechanical solution. The variable moment of inertia flywheel uses mechanical mass redistribution to achieve speed regulation and load smoothing. This mechanical substitution eliminates the need for electronic power converters, doubly fed induction generators, and complex control electronics, thereby reducing device complexity while maintaining structural load reduction benefits.
Solution Approach 2:
The flywheel system operates autonomously by automatically adjusting its moment of inertia in response to wind speed variations without requiring external electronic control. The mechanical system self-regulates by redistributing mass based on the kinetic energy available, eliminating the need for external control systems, sensors, and electronic power conversion equipment.
3Productivity
If the angular velocity of lift type vertical axis wind turbines increases, then the energy capture improves, but stall occurs due to rapid change of attack angle
Solution Approach 1:
The patent applies dynamics by making the moment of inertia variable to dynamically control angular velocity. When wind conditions cause angular velocity to increase to a level that would cause stall, the flywheel's moment of inertia increases, which naturally reduces the angular velocity back to the optimal range. This dynamic adjustment allows the turbine to capture maximum energy while preventing stall conditions.
Solution Approach 2:
The system provides automatic feedback control through the variable moment of inertia mechanism. As angular velocity increases, the centrifugal force redistributes the flywheel mass to increase moment of inertia, which in turn reduces angular velocity. This negative feedback loop automatically maintains angular velocity within the optimal range to prevent stall while maximizing energy capture.
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
This solution allows for efficient energy storage and regulation of angular velocity, reducing energy loss and preventing excessive velocities, applicable to any wind turbine size or orientation, and other mechanical systems, enhancing energy utilization and system stability.
Implementation Method 1
Conservation of angular momentum then demands a reduction of angular velocity of the system
Data Source
AI summary
A method for storage of excess energy which would otherwise be lost, the regulation of angular velocity, and prevention of excessive velocities is disclosed. The device consists of a bowl shaped container, divided into sections by radially oriented vertical walls, which holds a fluid (any appropriate liquid or set of small solid particles), and spins on its vertically oriented axis at various angular velocities. The floor of the device is formed in successive shapes of bowls and shelves, which allows for a kind of "gearing". The invention allows more and more energy to be input into the device while the angular velocity is regulated within a particular range. A typical embodiment of the invention would include its attachment by a shaft at the axis to a vertical axis wind turbine.