Browsing by Author "Marcos, Marga"
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Item Assembled PTO based on an array of double-acting hydraulic cylinders for WECs: From Conceptual Design to an Adjusted Detailed Model(2015-04-22) Antolín-Urbaneja, Juan Carlos; Cortes, A.; Marcos, Marga; Lasa, Joseba; Estensoro, Patxi; Cabanes, Itziar; Tecnalia Research & InnovationAll Wave Energy Converters (WECs) based on wave activated bodies comprises a Power Take- Off (PTO) system among other subsystems like the reaction mechanism, the supervisor of the system and the electrical generator. One of the most applied PTO systems consists of oil high pressure hydraulic devices. These devices are able to apply high forces, to store large quantities of energy through accumulators and to provide smoother power output to the motor coupled to a generator. In these systems the poor efficiency and the oil leakages contaminating the environment are considered main drawbacks. Despite of this, they are widely used in several promising WECs with the aim of optimizing the harvested wave energy along the time. The initial challenge to absorb an oscillating movement of ±30º at 5rad/s as a maximum angular speed absorbing up to 16000Nm from a specific WEC, led to the development of a simplified hydraulic model before manufacturing a PTO prototype to be verified in a Test Bench (Figure 1). The experimental results of PTO under different conditions have been used to adjust a full detailed PTO Model using Mathworks® software platform. This work presents a patented oil high pressure hydraulic PTO prototype based on an array of four double-acting hydraulic cylinders. This prototype has been designed and completely modelled as a proof concept at 1:4 scale being able to apply a variable Coulomb type damping torque through the activation of each hydraulic cylinder independently and through the modification of geometrical parameters easily. The complete model of the PTO has been accurately tuned up through adjustment of model parameters using the results of the experimental tests. This will allow the study of control strategies to optimize the extracted wave energy from a specific WEC, like point-absorbers.Item Comparative assessment of control strategies for the biradial turbine in the Mutriku OWC plant(2020-02) Faÿ, François-Xavier; Henriques, João C.; Kelly, James; Mueller, Markus; Abusara, Moahammad; Sheng, Wanan; Marcos, Marga; Tecnalia Research & Innovation; RENOVABLES EFICIENCIA ENERGETICA Y CIRCULARIDADTo be competitive against other renewable energy sources, energy converted from the ocean waves needs to reduce its associated levelised cost of energy. It has been proven that advanced control algorithms can increase power production and device reliability. They act throughout the power conversion chain, from the hydrodynamics of wave absorption to the power take-off to improve the energy yield. The present work highlights the development and test of several algorithms to control the biradial turbine which is to be installed in the Mutriku oscillating water column plant. A collection of adaptive and predictive controllers is explored and both turbine speed controllers and latching strategies are examined. A Wave-to-Wire model of one chamber of the plant is detailed and simulation results of six control laws are obtained. The controllers are then validated using an electrical test infrastructure to prepare the future deployment in the plant. Finally, the control strategies are assessed against criteria like energy production, power quality or reliability.Item Innovative Hydraulic Power Take-Off Construction and Performance Tests for Wave Energy Conversion(Trans Tech Publications Ltd, 2013) Antolín-Urbaneja, Juan Carlos; Lasa, Joseba; Estensoro, Patxi; Cabanes, Itziar; Marcos, Marga; Tecnalia Research & Innovation; ROBOTICA_AUTOMA; INNOV_AIR_MOBIL; GENERALThis document describes and demonstrates the features of a new innovative hydraulic Power take-Off (PTO) to be used for Wave Energy Conversion. This device is able to transform low frequency oscillating movement into a continuous high frequency angular speed, absorbing high fluctuated torque at the input shaft, which can reach up to 8000Nm. Moreover, the major breakthrough of this device is that it can control the braking torque through the modification of some geometrical parameters, L and R, and through the activation of more than one hydraulic cylinder together with the pressure. The output shaft of the PTO is able to rotate at different continuous rated speed through the actuation on a specific control valve at the inlet of the hydraulic motor. Tests to check the behavior of the PTO related to the smoothening of the power output and concerning the time needed to increase the high pressure and the time available after the accumulation of some quantity of energy in different initial conditions are presented.Item Modeling Innovative Power Take-Off Based on Double-Acting Hydraulic Cylinders Array for Wave Energy Conversion(2015-03-20) Antolín-Urbaneja, Juan Carlos; Cortes, A.; Cabanes, Itziar; Estensoro, Patxi; Lasa, Joseba; Marcos, Marga; Tecnalia Research & Innovation; ROBOTICA_AUTOMA; GENERAL; INNOV_AIR_MOBILOne of the key systems of a Wave Energy Converter for extraction of wave energy is the Power Take-Off (PTO) device. This device transforms the mechanical energy of a moving body into electrical energy. This paper describes the model of an innovative PTO based on independently activated double-acting hydraulic cylinders array. The model has been developed using a simulation tool, based on a port-based approach to model hydraulics systems. The components and subsystems used in the model have been parameterized as real components and their values experimentally obtained from an existing prototype. In fact, the model takes into account most of the hydraulic losses of each component. The simulations show the flexibility to apply different restraining torques to the input movement depending on the geometrical configuration and the hydraulic cylinders on duty, easily modified by a control law. The combination of these two actions allows suitable flexibility to adapt the device to different sea states whilst optimizing the energy extraction. The model has been validated using a real test bench showing good correlations between simulation and experimental testsItem A Power Take-Off Behaviour at High Pressure Operation Point, Using Four Double-acting Hydraulic Cylinders Modelled by a Port-based Approach(2015-09) Antolín-Urbaneja, Juan Carlos; Cortes, A.; Marcos, Marga; Lasa, Joseba; Cabanes, Itziar; Tecnalia Research & InnovationThis paper deals with the behaviour at high pressure operation points of a hydraulic Power Take-Off (PTO) using a highly detailed model based on four double-acting hydraulic cylinders modelled by a port-based approach. The developed model takes advantage of the availability of basic hydraulic components which can be parameterized based on real ones, including most of the hydraulic losses. With the aim of optimizing the extraction of wave energy, this PTO is able to modify its restraining torque through the independent activation of the hydraulic cylinders located in the primary transmission and modifying some geometrical parameters related to their fixation points respecting to the axis torque. The ultimate objective of this PTO is to provide a wide range of torques that can be modulated by modifying the operating high pressure of the HP accumulator, the combination of the available areas of the double-acting hydraulic cylinder and the location of their fixation points with respect to the applied movement. This factor can help to improve the control of WEC based on activated bodies with the aim to optimize the extraction of wave energy. In this paper an extended simulation results at different operation points and input movements are presented.Item Sea trial results of a predictive algorithm at the Mutriku Wave power plant and controllers assessment based on a detailed plant model(2020-02) Faÿ, François-Xavier; Robles, Eider; Marcos, Marga; Aldaiturriaga, Endika; Camacho, Eduardo F.; Tecnalia Research & Innovation; RENOVABLES EFICIENCIA ENERGETICA Y CIRCULARIDAD; RENOVABLES OFFSHOREImproving the power production in wave energy plants is essential to lower the cost of energy production from this type of installations. Oscillating Water Column is among the most studied technologies to convert the wave energy into a useful electrical one. In this paper, three control algorithms are developed to control the biradial turbine installed in the Mutriku Wave Power Plant. The work presents a comparison of their main advantages and drawbacks first from numerical simulation results and then with practical implementation in the real plant, analysing both performance and power integration into the grid. The wave-to-wire model used to develop and assess the controllers is based on linear wave theory and adjusted with operational data measured at the plant. Three different controllers which use the generator torque as manipulated variable are considered. Two of them are adaptive controllers and the other one is a nonlinear Model Predictive Control (MPC) algorithm which uses information about the future waves to compute the control actions. The best adaptive controller and the predictive one are then tested experimentally in the real power plant of Mutriku, and the performance analysis is completed with operational results. A real time sensor installed in front of the plant gives information on the incoming waves used by the predictive algorithm. Operational data are collected during a two-week testing period, enabling a thorough comparison. An overall increase over 30% in the electrical power production is obtained with the predictive control law in comparison with the reference adaptive controller.