Autonomous Buoy Power Management for Wave Energy

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Solution Overview

Problem

Autonomous wave energy converter (WEC) buoys face challenges in maintaining continuous power supply to their payloads due to varying wave conditions, leading to power generation inefficiencies and potential system failure, especially during calm or storm conditions, where power requirements are continuous but generation is not.

Innovation Solution

The system includes a power management system that selectively connects/disconnects loads, uses a brake system to minimize power draw during low wave activity, and employs sea state sensors to optimize energy extraction and distribution, allowing for autonomous operation and communication with a command center to adjust power delivery and duty cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the WEC operates continuously to generate power, then power supply to payload is maintained, but during calm conditions power generation becomes insufficient leading to battery depletion

Engineering Contradiction:
Improvecontinuous power supplyVSAvoidpower generation sufficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts its operational state based on wave conditions. During calm conditions, the WEC transitions to a low-power mode where non-essential loads are shed and the brake system is applied to minimize power consumption, while still maintaining essential payload operations. This dynamic adaptation allows the system to survive extended calm periods without battery depletion.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters based on environmental conditions. The brake force application, load shedding thresholds, and power management settings are adjusted according to wave amplitude and duration predictions. This parameter adaptation enables the WEC to optimize power generation during favorable conditions and minimize consumption during calm periods.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the WEC is locked up during storm conditions to prevent destruction, then survivability is ensured, but power generation stops completely

Engineering Contradiction:
ImprovesurvivabilityVSAvoidpower generation
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The payload is segmented into essential and non-essential components. During storm conditions, the WEC locks up to prevent destruction while maintaining power to essential loads only. The power management system selectively shuts down non-essential loads to minimize power consumption during the lock-up period, ensuring that limited stored energy is reserved for critical operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system prepares for storm conditions by predicting wave amplitude and duration. Before entering lock-up mode, the power management system pre-sheds non-essential loads and adjusts operational parameters to minimize power consumption. This preliminary action ensures that the WEC can survive extended lock-up periods with sufficient energy reserves.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the WEC consumes power for housekeeping needs, then operational functions are maintained, but during low amplitude waves all available stored energy is used up leaving none for the payload

Engineering Contradiction:
Improvehousekeeping functionVSAvoidavailable stored energy
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The power management system extracts and prioritizes essential functions from the total load. During low wave conditions, non-essential housekeeping functions are selectively shut down or reduced, while maintaining critical operational functions. This extraction approach ensures that limited stored energy is allocated to essential payload operations rather than being consumed by routine housekeeping tasks.

Inventive Principle:
Principle #2Taking out (Extraction)

4Extent of automation

If the WEC operates autonomously without operator intervention, then continuous monitoring and control is maintained, but system complexity increases

Engineering Contradiction:
Improveautonomous operationVSAvoidcontrol system
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The WEC implements self-service through autonomous power management. The control system continuously monitors wave conditions, battery state of charge, and load requirements, then automatically adjusts operational parameters without operator intervention. This self-service capability maintains continuous monitoring and control while managing system complexity through rule-based decision algorithms that respond to predefined environmental thresholds.

Inventive Principle:
Principle #25Self-service

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 extends the operational life of WEC buoys by managing power consumption and distribution, ensuring continuous power to payloads even under adverse wave conditions, enhancing their survivability and reliability over extended periods.

Implementation Method 1

a system for generating (electric) power in response to wave motion

Methodology Applied
Scientific EffectWave energy conversion: Electromagnetic Induction

Implementation Method 2

a braking system

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2691639B1Autonomously operated buoys with power generation and power usage control
Publication Date: 2016.11.30 OCEAN POWER TECHNOLOGIES INC
  • EP2691639B1 patent drawingFigure 1
  • EP2691639B1 patent drawingFigure 1A
  • EP2691639B1 patent drawingFigure 1B

AI summary

Apparatus, intended to be deployed in a body of water, includes a payload comprised of a multiplicity of different electronic and electromechanical loads and a wave energy converter (WEC) system responsive to the amplitude of waves in the body of water for producing electrical power, which is a function of the wave amplitudes, to power the payload. The apparatus includes switching circuitry for controlling the application of power to selected ones of the loads. Control circuitry and devices which are responsive to the electric power being produced control the switching circuitry for controlling the amount of power supplied to, and consumed by, the loads.