The Experts below are selected from a list of 84336 Experts worldwide ranked by ideXlab platform
M R Elmo - One of the best experts on this subject based on the ideXlab platform.
-
model predictive control of Sea Wave energy converters part i a convex approach for the case of a single device
2014Co-Authors: M R ElmoAbstract:This paper investigates model predictive control (MPC) of a single Sea Wave energy converter (WEC). By using control schemes which constrain certain quantities, such as the maximum size of the feedback force, the energy storage for actuators and relative heave motion, it is possible for control to not only improve performance but to directly impact strongly on design and cost. Motivated by this fact, a novel objective function is adopted in the MPC design, which brings obvious benefits: First, the quadratic program (QP) derived from this objective function can be easily convexified, which facilitates the employment of existing efficient optimization algorithms. Second, this novel design can trade off the energy extraction, the energy consumed by the actuator and safe operation. Moreover, an alternative QP is also formulated with the input slew rate as optimization variable, so that the slew rate limit of an actuator can be explicitly incorporated into optimization. All these benefits promote the real-time application of MPC on a WEC and reduced cost of hardware.
Yalcin Yuksel - One of the best experts on this subject based on the ideXlab platform.
-
black Sea Wave energy atlas from 13 years hindcasted Wave data
2013Co-Authors: Burak Aydogan, Berna Ayat, Yalcin YukselAbstract:Abstract The present study aims to evaluate the Wave energy potential of the Black Sea. Wave properties were calculated using 3rd generation Spectral Wave Model for years 1996–2009 by using wind data from European Center for Medium-Range Weather Forecasts (ECMWF). The Wave model was calibrated using the Wave measurements conducted at five different stations. Wave power atlas displaying time – averaged Wave power for entire Black Sea was generated. Also Wave power roses and Wave power distribution tables in means of periods and heights for different regions were presented. Wave energy found to be decreasing along the coast from west to east. It was found that the most energetic region is the South Western part of the Sea. The eastern part of the Black Sea is the least energetic in means of Wave power. It was concluded that the most promising location is the Thracian shores of Turkey, especially west side of Istanbul. Beside this, other promising locations in the Black Sea Basin were also evaluated. Annual Wave energies (kWh/m) for different regions were presented in this study.
Jens Peter Kofoed - One of the best experts on this subject based on the ideXlab platform.
-
the ssg Wave energy converter performance status and recent developments
2012Co-Authors: Diego Vicinanza, Lucia Margheritini, Jens Peter Kofoed, Mariano BuccinoAbstract:The Sea-Wave Slot-cone Generator (SSG) is a Wave Energy Converter based on the Wave overtopping principle; it employs several reservoirs placed on top of each other, in which the energy of incoming Waves is stored as potential energy. Then, the captured water runs through turbines for electricity production. The system works under a wide spectrum of different Wave conditions, giving a high overall efficiency. It can be suitable for shoreline and breakwater applications and presents particular advantages, such as sharing structure costs, availability of grid connection and recirculation of water inside the harbor, as the outlet of the turbines is on the rear part of the system. Recently, plans for the SSG pilot installations are in progress at the Svaaheia site (Norway), the port of Hanstholm (Denmark) and the port of Garibaldi (Oregon, USA). In the last-mentioned two projects, the Sea-Wave Slot-cone Generator technology is integrated into the outer harbor breakwater and jetty reconstruction projects. In the last years extensive studies have been performed on the hydraulic and the structural response of this converter, with the aim of optimizing the design process. The investigations have been conducted by physical model tests and numerical simulations and many results have been published on both conference proceedings and journals. The main scope of this paper is reviewing the most significant findings, to provide the reader with an organic overview on the present status of knowledge.
-
extreme loads on the mooring lines and survivability mode for the Wave dragon Wave energy converter
2011Co-Authors: Stefano Parmeggiani, Jens Peter Kofoed, Erik FriismadsenAbstract:One of the main challenges Wave Energy Converters have to face on the road towards commercialization is to ensure survivability in extreme condition at a reasonable capital costs. For a floating device like the Wave Dragon, a reliable mooring system is essential. The control strategy of the Wave Dragon aims at optimizing the power production by adapting the floating level to the incoming Waves and by activating the hydro-turbines and regulating their working speed. In extreme conditions though, the control strategy could be changed in order to reduce the forces in the mooring system, lowering the design requirements with almost no added cost. The paper presents the result of the tank testing of a 1:51.8 scale model of a North Sea Wave Dragon in extreme Wave conditions of up to 100 years of return period. The results show that the extreme loads in the main mooring line can be reduced by approximately 20-30% by lowering the crest level and balancing the device to lean a little towards the front.
-
extreme loads on the mooring lines and survivability mode for the Wave dragon Wave energy converter
2011Co-Authors: Stefano Parmeggiani, Jens Peter Kofoed, Erik FriismadsenAbstract:One of the main challenges Wave Energy Converters have to face on the road towards commercialization is to ensure survivability in extreme condition at a reasonable capital costs. For a floating device like the Wave Dragon, a reliable mooring system is essential. The control strategy of the Wave Dragon aims at optimizing the power production by adapting the floating level to the incoming Waves and by activating the hydro-turbines and regulating their working speed. In extreme conditions though, the control strategy could be changed in order to reduce the forces in the mooring system, lowering the design requirements with almost no added cost. The paper presents the result of the tank testing of a 1:51.8 scale model of a North Sea Wave Dragon in extreme Wave conditions of up to 100 years of return period. The results show that the extreme loads in the main mooring line can be reduced by approximately 20-30% by lowering the crest level and balancing the device to lean a little towards the front.
Arne Wolfbrandt - One of the best experts on this subject based on the ideXlab platform.
-
multiphysics simulation of Wave energy to electric energy conversion by permanent magnet linear generator
2005Co-Authors: Mats Leijon, Hans Bernhoff, Olov Agren, Jan Isberg, Jan Sundberg, Marcus Berg, Karl Erik Karlsson, Arne WolfbrandtAbstract:The possibility to use three-phase permanent magnet linear generators to convert Sea Wave energy into electric energy is investigated by multiphysics simulations. The results show a possibility, which needs to be further verified by experimental tests, for a future step toward a sustainable electric power production from ocean Waves by using direct conversion. The results suggest that Wave energy can have an impact on tomorrow's new sustainable electricity production, not only for large units, but also for units ranging down to 10 kW. This gives Wave power a larger economical potential than previously estimated. The study demonstrates the feasibility of computer simulations to give a broad, and in several aspects a detailed, understanding of the energy conversion. The simulation results also give a useful starting point for future experimental work.
Giuliana Mattiazzo - One of the best experts on this subject based on the ideXlab platform.
-
productivity analysis of the full scale inertial Sea Wave energy converter prototype a test case in pantelleria island
2015Co-Authors: Andrea Cagninei, Giuliana Mattiazzo, Ermanno Giorcelli, Giovanni Bracco, Mattia Raffero, Davide PoggiAbstract:Wave power is one of the most rich and promising sources of renewable energy for the future. Approximately 2000 TWh/year can be produced through the exploitation of the Wave energy potential. In the past four decades, hundreds of Wave Energy Converters have been proposed and studied, but so far a conclusive architecture to harvest Wave power has not been identified. Many engineering problems are still to be solved; these include survivability, durability, and effective power capture in a variable Wave climate. Reacting body devices use the inertia of a large mass to generate the reaction needed from the power take off (PTO). Heretically, in the case of a simple inertial mass, optimal control adjusts the dynamic parameters of the PTO, such as the spring constant and energy absorbing damping, to maximize energy absorption. The ISWEC (Inertial Sea Wave Energy Converter) uses a gyroscope to create an internal inertial reaction that is able to harvest Wave power without exposing mechanical parts to the harsh o...
-
performance assessment of a 2 dof gyroscopic Wave energy converter
2015Co-Authors: Alessandro Battezzato, Giovanni Bracco, Ermanno Giorcelli, Giuliana MattiazzoAbstract:Wave Power is one of the most investigated energy sources today. So far, several devices have been tested and built up to the pre-commercial stage. ISWEC (Inertial Sea Wave Energy Converter) has developed at the Politecnico di Torino, exploiting gyroscopes to extract Wave energy. It allows power extraction without using any moving part immersed into water. The previous version of ISWEC presented 1 DOF (Degree Of Freedom), therefore requiring alignment of the device to the incoming Wave; this paper describes a novel version of ISWEC, with 2 DOFs and consequently able to absorb power from every Wave direction. The kinematics and the dynamics of the device are investigated, in order to compare the 1 DOF and the 2 DOF architectures from the point of view of the extracted power. The resulting simulations show that the 1 DOF prototype is more efficient when aligned with the incoming Wave, while the behavior of the 2 DOF device is substantially independent of the Wave direction. Such a difference of the performances is quantified and discussed along with considerations on the design and realization of the full-scale prototype.
-
hardware in the loop test rig for the iswec Wave energy system
2015Co-Authors: Giovanni Bracco, Giuliana Mattiazzo, Ermanno Giorcelli, Vincenzo Orlando, Mattia RafferoAbstract:The Hardware-In-the-Loop (HIL) simulation is a powerful mean to reduce costs in the design and manufacturing process of an engineering system. HIL techniques allow to use real components inside a simulation of a mathematical model. In this work such techniques are used on the ISWEC Wave energy system. ISWEC (Inertial Sea Wave Energy Converter) converts Sea Waves energy to electric energy by means of the gyroscopic effects produced by a spinning flywheel. The peculiarity of the system lays in the fact that all the moving parts needed to produce energy are Sealed inside a hull and therefore protected from the aggressive ocean climate. During the reSearch process on the ISWEC, the gyroscope and the electric generator have been manufactured and mounted on a test rig able to simulate the Wave actions on the hull of ISWEC. Those real parts of the system have been replaced inside the full mathematical model of ISWEC. Such HIL system is validated against real Wave tank tests carried out at the INSeaN in Rome. The HIL simulations proved to reproduce the real behavior in water Waves of ISWEC with errors as small as the 10%.
-
linear tubular permanent magnet generators for the inertial Sea Wave energy converter
2014Co-Authors: Luigi Cappelli, Fabrizio Marignetti, Giuliana Mattiazzo, Ermanno Giorcelli, Giovanni Bracco, Silvio Carbone, C AttaianeseAbstract:Marine energy represents a very promising source of energy available worldwide. Although this energy is available in several forms, Wave energy is the more widespread source characterized by high power density. In order to exploit energy from Waves, numerous systems have been designed and commercialized. The Inertial Sea Wave Energy Converter is a device based on a floating body slack-moored to the Seabed, using a gyroscope as a reference frame to produce electric power. This paper describes the design of the proposed converter equipped with two linear tubular permanent-magnet generators, exploiting the reciprocating motion between the gyroscopic system and the hull to generate power. The design of a two-phase linear tubular generator is analyzed. Experimental tests on a scale prototype have been performed.
-
iswec a gyroscopic mechanism for Wave power exploitation
2011Co-Authors: Giovanni Bracco, Ermanno Giorcelli, Giuliana MattiazzoAbstract:Abstract In the past four decades, hundreds of Wave Energy Converters (WECs) have been proposed and studied, but so far a final architecture to harvest Wave power has not been identified. Many engineering problems are still to be solved, like survivability, durability and effective power capture in a variable Wave climate. ISWEC (Inertial Sea Wave Energy Converter) is a system using the gyroscopic reactions provided from a spinning flywheel to extract power. The flywheel works inside a Sealed floating body in order to be protected from the outer environment and grant a reliable and durable operation. The article summarizes the design procedure of a 1:45 scaled ISWEC device with rated power 2.2 W and the tank tests performed with a simplified plain float to verify the actual prototype power capabilities. The article then focuses on the implementation of a non-linear coupled model (mechanics + hydrodynamics) to improve the float shape in order to maximize the power absorption. The final result is a float shape capable to absorb a power almost three times bigger (5.96 W) than the initial float shape.