Wave Energy Converter Spring Segmentation for Compact Natural Period
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Solution Overview
Problem
Existing wave energy converter systems face challenges such as complex and expensive components due to marine growth, corrosion, and viscous damping, which limit energy collection, and require long springs that are impractical to construct within the float for achieving desired natural periods.
Innovation Solution
A wave energy converter system with a float exposed to surface waves, an internal oscillator formed by a reaction mass and a compact spring mechanism, such as a pulley system, scissor mechanism, or hydraulic cylinder, to reduce the length and increase the stiffness of the spring, allowing for efficient energy conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a long spring is used to achieve the desired natural period, then the natural period is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The spring function is segmented into multiple components: a primary spring element and a secondary spring element connected in series. This segmentation allows each spring to be shorter and more manageable while collectively providing the required natural period, resolving the contradiction between achieving the desired natural period and avoiding complex spring construction.
2Duration of action of moving object
If a long spring is used to achieve the desired natural period, then the natural period is improved, but the ease of manufacture deteriorates
Solution Approach 1:
The spring function is segmented into multiple components: a primary spring element and a secondary spring element connected in series. This segmentation allows each spring to be shorter and more manageable while collectively providing the required natural period, resolving the contradiction between achieving the desired natural period and avoiding complex spring construction.
3Ease of manufacture
If the spring length is reduced, then the ease of manufacture is improved, but the stiffness must be increased to maintain natural period
Solution Approach 1:
The spring function is segmented into multiple components: a primary spring element and a secondary spring element connected in series. This segmentation allows each spring to be shorter and more manageable while collectively providing the required natural period, resolving the contradiction between achieving the desired natural period and avoiding complex spring construction.
Solution Approach 2:
The system uses a composite spring arrangement combining a primary spring element and a secondary spring element with different characteristics. This composite approach allows the shorter springs to achieve the required overall stiffness and natural period through their combined effect, resolving the contradiction between reduced length and maintained stiffness.
4Ease of manufacture
If the spring stiffness is increased, then the natural period is maintained with shorter spring, but the energy collection efficiency may be reduced
Solution Approach 1:
The spring function is segmented into multiple components: a primary spring element and a secondary spring element connected in series. This segmentation allows each spring to be shorter and more manageable while collectively providing the required natural period, resolving the contradiction between achieving the desired natural period and avoiding complex spring construction.
Solution Approach 2:
The system optimizes the parameters of both spring elements (stiffness, length, mass) to achieve the desired natural period while maximizing energy collection efficiency. By carefully selecting the stiffness and length parameters of the segmented springs, the system maintains optimal performance without requiring excessive stiffness that would reduce energy collection efficiency.
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 system effectively converts wave energy into electrical energy by using compact spring mechanisms, reducing the length and increasing the stiffness of the spring, making it practical to construct and improving energy collection efficiency while minimizing the pre-deployed mass.
Implementation Method 1
a spring that connects the reaction mass to the float
Implementation Method 2
a power take-off device that converts the mechanical energy available from the relative motion between the float and the reaction mass into electrical energy
Data Source
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AI summary
A wave energy converter (WEC) includes a shell (10) suitable for being placed within a body of water. The shell (10) contains an internal oscillator comprising a "reaction mass" (20) and a spring mechanism (30) coupled between the reaction mass (20) and the shell (10). The shell (10) and internal oscillator are constructed such that, when placed in a body of water and in response to waves in the body of water, there is relative motion betweenl the shell (10) and the internal oscillator's mass (20). A power take-off (PTO) device (40) is coupled-between the internal oscillator and the shell (10) to convert their relative motion into electric energy. In systems embodying the invention, the spring mechanism (30) is designed such that its displacement or movement is less than the displacement or movement of the reaction mass (20). The spring mechanism (30) may be any device which enables the reaction mass to undergo a given replacement while its displacement or movement is less than that of the reaction mass (20). This property enables the size of the WEC to be more readily controlled (e.g., made smaller).