Tethered Flying Object Control for Wind Energy Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wind energy conversion systems using tethered flying objects with stiff airfoils are limited by lack of manoeuvrability, leading to inefficient energy conversion due to restricted flight paths and higher depower phases, resulting in lower average power generation.
Innovation Solution
A method for controlling a flying object with a stiff airfoil using differential movement of two tethers to achieve roll movements, allowing lateral turns and efficient flight paths, combined with a device for changing the angle of attack to optimize power phases and depower phases, thereby enhancing manoeuvrability and energy conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a flying object with a stiff airfoil is used, then the structure provides stability and predictable aerodynamic characteristics, but the manoeuvrability is limited due to inability to perform arc flight paths
Solution Approach 1:
The patent applies dynamics by enabling the stiff airfoil flying object to perform rolling movements through differential tether length adjustments. This allows the object to dynamically change its orientation and flight path, transitioning from static stability to active manoeuvrability while maintaining structural rigidity
2Device complexity
If the flying object is restricted to vertical plane movement, then the control system is simplified, but the energy conversion efficiency decreases due to inability to maintain power phase
Solution Approach 1:
The patent transitions the flight path from a two-dimensional vertical plane to a three-dimensional curved path by incorporating lateral rolling movements. This dimensional expansion allows the flying object to maintain tether alignment with wind direction while executing figure-eight patterns, significantly improving energy conversion efficiency
3Reliability
If the depower phase duration is increased, then the flying object can be reeled in safely, but the average power generation decreases due to reduced power phase time proportion
Solution Approach 1:
The patent implements periodic figure-eight flight patterns that systematically alternate between power phases (energy generation) and depower phases (retraction). This periodic motion optimizes the time proportion of each phase, maintaining safety while maximizing average power output through efficient cycling
4Device complexity
If only two tethers are used, then the system complexity is reduced, but the manoeuvrability is insufficient for complex flight paths
Solution Approach 1:
The patent employs asymmetric control by applying different lengths to the two tethers to induce rolling movements. This asymmetric tether configuration enables lateral manoeuvring and figure-eight flight patterns, achieving complex manoeuvrability with a simple two-tether system
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 enables more efficient conversion of wind energy into electrical energy by allowing the flying object to maintain a lying or standing figure-eight flight path, reducing depower phase duration and increasing average power generation by optimizing reel out and reel in speeds.
Implementation Method 1
a flying object (2, 20) generates work in a power phase by pulling on the tethers (3, 4) reeled out from the ground station (5)
Implementation Method 2
in the depower phase the motor (9) drives the winch (7) to reel in the tethers (3, 4)
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
The method according to the invention for controlling a flying object (2, 20) having a stiff airfoil ( 21 ) and being controllable by means of a roll movement for carrying out lateral turns, with which the flying object (2, 20) is connected to a ground station (5) by means of at least two tethers (3, 4), such that the flying object ( 2, 20) rolls during flight by means of a differential movement of the tethers (3, 4), and that the flying object (2, 20) is rolled during flight by means of such differential movements and is th us manoeuvred by means of the turning flight that is caused in this way. Said flying object (2, 20) can be operated by means of the controlling reel out speed and reel in speed with an average power maximised over a flight cycle consisting of a power phase and a depower phase.