Wave Power Torque Control via Virtual Reflection
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Solution Overview
Problem
The existing wave power generation systems face inefficiencies due to the mismatch in energy from incident and reflected waves, leading to suboptimal power generation as the torque command is set based on either wave energy, resulting in either non-movement during high resistance or inadequate power generation.
Innovation Solution
A wave power generation system with a wave receiving member near a virtual reflection surface, a ram cylinder hydraulic pump, an accumulator, and a controller that adjusts the torque command based on the differential value detected by a change value sensor to differentiate between incident and reflected wave energies, ensuring efficient power generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the torque command is set high based on incident wave energy, then power generation efficiency is improved during incident waves, but the wave receiving member does not move during reflected waves due to excessively high resistance
Solution Approach 1:
The torque command is made dynamic by switching between two different values based on the wave type (incident or reflected) detected by the swing direction detector. This allows the system to adapt the resistance level to match the current wave conditions, resolving the contradiction between maintaining high power generation efficiency and ensuring the wave receiving member can still move.
Solution Approach 2:
The torque command parameter is changed based on the detected swing direction. When an incident wave is detected, a first torque command (higher value) is applied to maximize power generation. When a reflected wave is detected, a second torque command (lower value) is applied to reduce resistance and allow movement, thus resolving the contradiction through parameter adaptation.
2Ease of operation
If the torque command is set low based on reflected wave energy, then the wave receiving member can move during reflected waves, but the power generator cannot adequately generate electric power during incident waves
Solution Approach 1:
The system dynamically adjusts the torque command based on real-time detection of wave type. During incident waves, the higher torque command ensures adequate power generation, while during reflected waves, the lower torque command enables movement. This dynamic adaptation resolves the contradiction between movement capability and power generation efficiency.
Solution Approach 2:
The torque command parameter is switched between two distinct values based on the detected swing direction. The first torque command value is used during incident waves to maximize power generation, while the second torque command value is used during reflected waves to ensure movement capability, thus resolving the contradiction through conditional parameter changes.
3Device complexity
If a single torque command is used for both incident and reflected waves, then the system structure is simple, but power generation efficiency deteriorates due to energy mismatch
Solution Approach 1:
While maintaining relatively simple system structure, the torque command is made dynamic by switching between two predefined values based on swing direction detection. This dynamic approach allows the system to optimize power generation efficiency for different wave types without requiring complex continuous control mechanisms.
Solution Approach 2:
The torque command parameter is changed based on the detected wave type, switching between a first value for incident waves and a second value for reflected waves. This parameter adaptation enables the system to maintain high power generation efficiency across different wave conditions while keeping the control system relatively simple.
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 configuration allows for improved power generation efficiency by accurately accounting for the energy from both incident and reflected waves, optimizing the torque command to enhance electric power generation.
Implementation Method 1
a wave receiving member provided near a virtual reflection surface configured to reflect a coming incident wave, the wave receiving member being configured to swing toward a first side in a swing direction by receiving force of the incident wave and swing toward a second side in the swing direction by receiving force of a reflected wave reflected by the virtual reflection surface
Implementation Method 2
a ram cylinder hydraulic pump configured to convert a swinging motion of the wave receiving member into a linear motion to discharge an operating liquid to a main passage
Implementation Method 3
an accumulator configured to accumulate, under pressure, the operating liquid discharged from the hydraulic pump device and discharge the accumulated operating liquid when pressure in the main passage decreases
Implementation Method 4
a hydraulic motor configured to be supplied with the operating liquid flowing through the main passage and drive an output shaft of the hydraulic motor based on an output value corresponding to pressure and flow rate of the supplied operating liquid
Implementation Method 5
a power generator configured to generate electric power corresponding to the output value given to the output shaft of the hydraulic motor
Data Source
Figure 1
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AI summary
A wave power generation system includes a wave receiving member, a ram cylinder hydraulic pump device, a change value sensor, an accumulator device, a hydraulic motor, a power generator, and a controller. The wave receiving member is arranged near a virtual reflection surface configured to reflect a coming incident wave. The controller sets a torque command used when the power generator generates electric power. Based on a differential value of a change value that is detected by the change value sensor and changes in accordance with a swing amount of the wave receiving member, the controller determines whether the wave receiving member is swinging toward a first side or second side in a swing direction. When the controller determines that the wave receiving member is swinging toward the second side in the swing direction by receiving force of a reflected wave reflected by the virtual reflection surface, the controller changes the torque command from the torque command set when the controller determines that the wave receiving member is swinging toward the first side in the swing direction by receiving force of the incident wave.