Gyroscope WEC Control for Robust Wave Energy Extraction
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Solution Overview
Problem
Existing wave energy conversion systems using PID and MPC controllers are inefficient due to variations in sea wave states and random disturbances, leading to suboptimal energy extraction.
Innovation Solution
A Tube-Based Robust Model Predictive Control (TRMPC) system is implemented to drive the future evolution of gyroscope structure states, using a predictive control model and a nominal convergence module to minimize errors and maintain optimal energy extraction despite uncertainties and disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If PID controllers with pre-set gain-scheduling are used, then the control system is simple to implement, but the extracted energy is suboptimal due to mismatch between tabulated control parameters and actual wave motion conditions
Solution Approach 1:
The patent transitions from static PID gain-scheduling to dynamic MPC control that continuously adapts control parameters based on real-time wave conditions. The controller dynamically optimizes the resistive drive torque by solving predictive optimization problems at each control step, allowing the system to respond to actual wave motion rather than relying on pre-computed tables, thereby resolving the contradiction between implementation simplicity and energy extraction optimality
Solution Approach 2:
The MPC controller implements continuous feedback from wave motion sensors and system state measurements to adjust control parameters in real-time. This feedback mechanism allows the controller to correct deviations from optimal performance caused by uncertainties in wave forecasts or changes in sea state, maintaining high energy extraction efficiency without requiring overly complex implementation
2Adaptability or versatility
If MPC controllers with state evolution models are used, then the control adapts to wave motion, but errors due to model inaccuracies and random disturbances reduce control robustness
Solution Approach 1:
The patent employs robust MPC techniques that anticipate and cushion against model inaccuracies and disturbances before they significantly impact performance. By incorporating uncertainty models and using robust optimization formulations, the controller pre-adjusts control actions to compensate for expected deviations, maintaining reliability despite model errors and random wave disturbances
Solution Approach 2:
The continuous feedback mechanism in the MPC controller monitors actual system behavior against predicted behavior, detecting model errors and disturbances in real-time. This feedback enables the controller to correct trajectory deviations and maintain robust performance by adjusting control parameters based on actual rather than predicted system responses
3Productivity
If the opposing resistive drive torque is modulated to maximize extracted power, then energy extraction efficiency increases, but the control system becomes more complex
Solution Approach 1:
The patent replaces complex mechanical control mechanisms with advanced computational control algorithms. Instead of using complex mechanical linkages or hydraulic systems to modulate the resistive drive torque, the system uses MPC algorithms that compute optimal torque commands based on wave predictions and system state, achieving high energy extraction efficiency through software-based control rather than mechanical complexity
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 TRMPC system enhances the robustness and efficiency of wave energy conversion by maintaining optimal energy extraction even in the presence of external perturbations and model uncertainties, achieving a maximum error reduction of approximately 2% under varying conditions.
Implementation Method 1
The generator is able to convert, by the motion of a flywheel, the rotational energy due to the oscillation of the hull and induced by the wave power into electrical energy
Implementation Method 2
by applying an counteracting resistive drive torque, which acts mainly as a damper, and by operating in the even quadrants of the V-I diagram of the driver/inverter, an electric power can be generated through the electric motor
Implementation Method 3
inertial-type WEC or ISWEC plants, use a reacting body or PTO that exploits the inertia of a large mass to generate a reaction and to extract its power
Implementation Method 4
equipped with directional gyroscopic converters, each of which is connected to an electric power generator
Data Source
AI summary
A controller of a gyroscope structure associated with a floating hull and equipped with an electrical converter suitable for converting the rotational energy of the floating hull into electrical energy, the controller, receiving as input a perturbed output state including operating variables of the gyroscope structure to determine a driving signal of the electrical converter, which includesa first signal portion determined using a predictive control model of the gyroscope structure computed on the basis of the perturbed output state anda second signal portion determined using a tube convergence computed on parametric deviations of the operating variables of the perturbed output state, the parametric deviations computed with respect to the operating variables of a unperturbed output nominal state of the gyroscope structure.