The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Nand Kishor - One of the best experts on this subject based on the ideXlab platform.
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event triggered nonlinear control of owc ocean Wave energy plant
IEEE Transactions on Sustainable Energy, 2018Co-Authors: Sunil Kumar Mishra, Shubhi Purwar, Nand KishorAbstract:This paper presents event-triggered nonlinear controllers for oscillating water column (OWC) ocean Wave energy plant. The study is based on event-triggered backstepping controller (ET-BSC) and event-triggered sliding mode controller (ET-SMC) to control the rotational speed of an OWC turbine coupled to a generator. The designed controllers are capable to avoid the stalling of the Wells turbine so as to maximize its output power. The aim of event-triggered control is to minimize the control updates, thus providing efficient utilization of resources without compromising the OWC performance. In this regard, aperiodic sampling has been applied using an event-triggering rule derived from Lyapunov stability analysis. In order to validate the proposed controllers, simulation results have been performed using a JONSWAP Irregular Wave model. It is observed that performance of the ET-BSC is better than the ET-SMC in terms of defined indices, control effort, and inter-event execution time.
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an optimal and non linear speed control of oscillating water column Wave energy plant with wells turbine and dfig
2016Co-Authors: Sunil Kumar Mishra, Shubhi Purwar, Nand KishorAbstract:This paper presents controller scheme to maximize the turbine output power and thereby improve the efficiency in oscillating water column (OWC) Wave power plant equipped with Wells turbine and doubly fed induction generator (DFIG). The scheme is based on flow coefficient estimation and controller design for tracking of rotational speed. Initially, a linear reference tracking (LRT) approach is applied to achieve the maximized output power by establishing a linear relationship between reference rotational speed and input pressure drop. This follows implementation of fuzzy theory based maximum power point tracking (FMPPT) approach to provide the optimal speed reference. Then, a backstepping (BS) controller is designed to track reference rotational speed of DFIG so as to improve the output power. The BS controller is derived using Lyapunov stability theorem which ensures the stability of the overall closed loop system. The advantages of the proposed control scheme over conventional PI control and the uncontrolled system is demonstrated for regular Waves and Irregular Waves. Finally, the FMPPT-BS control approach has been validated with JONSWAP Irregular Wave model.
Manabu Takao - One of the best experts on this subject based on the ideXlab platform.
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Air Turbines for Wave Energy Conversion
International Journal of Rotating Machinery, 2012Co-Authors: Manabu Takao, Toshiaki SetoguchiAbstract:This paper describes the present status of the art on air turbines, which could be used for Wave energy conversion. The air turbines included in the paper are as follows: Wells type turbines, impulse turbines, radial turbines, cross-flow turbine, and Savonius turbine. The overall performances of the turbines under Irregular Wave conditions, which typically occur in the sea, have been compared by numerical simulation and sea trial. As a result, under Irregular Wave conditions it is found that the running and starting characteristics of the impulse type turbines could be superior to those of the Wells turbine. Moreover, as the current challenge on turbine technology, the authors explain a twin-impulse turbine topology for Wave energy conversion.
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current status of self rectifying air turbines for Wave energy conversion
Energy Conversion and Management, 2006Co-Authors: Toshiaki Setoguchi, Manabu TakaoAbstract:This paper reviews the present state of the art on self rectifying air turbines, which could be used for Wave energy conversion. The overall performances of the turbines under Irregular Wave conditions, which typically occur in the sea, have been evaluated numerically and compared from the viewpoints of their starting and running characteristics. The types of turbine included in the paper are: (a) Wells turbine with guide vanes (WTGV); (b) turbine with self-pitch-controlled blades (TSCB); (c) biplane Wells turbine with guide vanes (BWGV); (d) impulse turbine with self-pitch-controlled guide vanes (ISGV); and (e) impulse turbine with fixed guide vanes (IFGV). As a result, under Irregular Wave conditions, it is found that the running and starting characteristics of impulse type turbines could be superior to those of the Wells turbine. Moreover, the authors have explained the mechanism of the hysteretic behavior of the Wells turbine and the necessity of links for improvement of the performance of the ISGV.
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Study on an impulse turbine for Wave energy conversion
International Journal of Offshore and Polar Engineering, 1999Co-Authors: Toshiaki Setoguchi, Manabu Takao, Y. Kinoue, S. SanthakumarAbstract:The objective of this paper is to clarify the performance of impulse turbine with fixed guide vanes and to compare it with that of Wells turbine with guide vanes. As a result, a suitable choice of the design factors for the impulse turbine was shown for the inlet angle of rotor blade and the shape of guide vane. Furthermore, it was found that the running and starting characteristics of the impulse turbine were superior to those of the Wells turbine under Irregular Wave condition.
A.f. De O. Falcão - One of the best experts on this subject based on the ideXlab platform.
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Wave power extraction of a heaving floating oscillating water column in a Wave channel
Renewable Energy, 2016Co-Authors: R P F Gomes, Luís M.c. Gato, J C C Henriques, A.f. De O. FalcãoAbstract:Abstract The performance evaluation of a Wave energy converter in Wave channel is influenced by the hydrodynamic effects caused by the near presence of the side walls. Since this phenomenon is not observed in the open ocean, it is important to assess the walls influence in the converter dynamics when analysing experimental results. This paper studies the dynamics and power extraction of an axisymmetric floating oscillating water column (OWC) device, the Spar-buoy OWC, using experimental data obtained in a Wave channel. A two heaving body model (spar-buoy and OWC) based on linear forces is formulated in the frequency domain. Linear hydrodynamic coefficients are obtained from a boundary integral equation method. The presence of the channel side walls is simulated approximately by a periodic array of devices, and alternatively by two finite-length walls. Linearized drag forces are derived from small-scale model tests. Power extraction results are presented for regular and Irregular Waves. The numerical simulations show that the wall effect may amplify the power capture up to a maximum of 15% for regular Waves and 10% for Irregular Wave conditions, for a channel-width-to-device-diameter ratio equal to 5.25.
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latching control of a floating oscillating water column Wave energy converter
Renewable Energy, 2016Co-Authors: J C C Henriques, Luís M.c. Gato, A.f. De O. Falcão, Eider Robles, Francoisxavier FayAbstract:The OWC spar-buoy is an axisymmetric floating version of an oscillating-water-column (OWC) based device whose power take-off (PTO) system is an air turbine/generator set. Latching has been regarded as one of the most promising techniques to improve the efficiency of Wave energy converters. In the case of the OWC spar-buoy, latching control is performed by opening/closing a high-speed stop valve installed in series with the turbine. The present paper has three main objectives. Firstly, to assess the performance improvements that can be achieved with a latching control strategy within a receding horizon framework. Secondly, to establish the practical requirements of this type of control by evaluating the sensitivity of the turbine power output to several receding horizon time intervals. Finally, to test and validate experimentally the proposed algorithms in a small-scale PTO test rig. All the experimental tests were performed considering Irregular Wave conditions.
Toshiaki Setoguchi - One of the best experts on this subject based on the ideXlab platform.
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Air Turbines for Wave Energy Conversion
International Journal of Rotating Machinery, 2012Co-Authors: Manabu Takao, Toshiaki SetoguchiAbstract:This paper describes the present status of the art on air turbines, which could be used for Wave energy conversion. The air turbines included in the paper are as follows: Wells type turbines, impulse turbines, radial turbines, cross-flow turbine, and Savonius turbine. The overall performances of the turbines under Irregular Wave conditions, which typically occur in the sea, have been compared by numerical simulation and sea trial. As a result, under Irregular Wave conditions it is found that the running and starting characteristics of the impulse type turbines could be superior to those of the Wells turbine. Moreover, as the current challenge on turbine technology, the authors explain a twin-impulse turbine topology for Wave energy conversion.
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current status of self rectifying air turbines for Wave energy conversion
Energy Conversion and Management, 2006Co-Authors: Toshiaki Setoguchi, Manabu TakaoAbstract:This paper reviews the present state of the art on self rectifying air turbines, which could be used for Wave energy conversion. The overall performances of the turbines under Irregular Wave conditions, which typically occur in the sea, have been evaluated numerically and compared from the viewpoints of their starting and running characteristics. The types of turbine included in the paper are: (a) Wells turbine with guide vanes (WTGV); (b) turbine with self-pitch-controlled blades (TSCB); (c) biplane Wells turbine with guide vanes (BWGV); (d) impulse turbine with self-pitch-controlled guide vanes (ISGV); and (e) impulse turbine with fixed guide vanes (IFGV). As a result, under Irregular Wave conditions, it is found that the running and starting characteristics of impulse type turbines could be superior to those of the Wells turbine. Moreover, the authors have explained the mechanism of the hysteretic behavior of the Wells turbine and the necessity of links for improvement of the performance of the ISGV.
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Study on an impulse turbine for Wave energy conversion
International Journal of Offshore and Polar Engineering, 1999Co-Authors: Toshiaki Setoguchi, Manabu Takao, Y. Kinoue, S. SanthakumarAbstract:The objective of this paper is to clarify the performance of impulse turbine with fixed guide vanes and to compare it with that of Wells turbine with guide vanes. As a result, a suitable choice of the design factors for the impulse turbine was shown for the inlet angle of rotor blade and the shape of guide vane. Furthermore, it was found that the running and starting characteristics of the impulse turbine were superior to those of the Wells turbine under Irregular Wave condition.
J C C Henriques - One of the best experts on this subject based on the ideXlab platform.
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Wave power extraction of a heaving floating oscillating water column in a Wave channel
Renewable Energy, 2016Co-Authors: R P F Gomes, Luís M.c. Gato, J C C Henriques, A.f. De O. FalcãoAbstract:Abstract The performance evaluation of a Wave energy converter in Wave channel is influenced by the hydrodynamic effects caused by the near presence of the side walls. Since this phenomenon is not observed in the open ocean, it is important to assess the walls influence in the converter dynamics when analysing experimental results. This paper studies the dynamics and power extraction of an axisymmetric floating oscillating water column (OWC) device, the Spar-buoy OWC, using experimental data obtained in a Wave channel. A two heaving body model (spar-buoy and OWC) based on linear forces is formulated in the frequency domain. Linear hydrodynamic coefficients are obtained from a boundary integral equation method. The presence of the channel side walls is simulated approximately by a periodic array of devices, and alternatively by two finite-length walls. Linearized drag forces are derived from small-scale model tests. Power extraction results are presented for regular and Irregular Waves. The numerical simulations show that the wall effect may amplify the power capture up to a maximum of 15% for regular Waves and 10% for Irregular Wave conditions, for a channel-width-to-device-diameter ratio equal to 5.25.
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latching control of a floating oscillating water column Wave energy converter
Renewable Energy, 2016Co-Authors: J C C Henriques, Luís M.c. Gato, A.f. De O. Falcão, Eider Robles, Francoisxavier FayAbstract:The OWC spar-buoy is an axisymmetric floating version of an oscillating-water-column (OWC) based device whose power take-off (PTO) system is an air turbine/generator set. Latching has been regarded as one of the most promising techniques to improve the efficiency of Wave energy converters. In the case of the OWC spar-buoy, latching control is performed by opening/closing a high-speed stop valve installed in series with the turbine. The present paper has three main objectives. Firstly, to assess the performance improvements that can be achieved with a latching control strategy within a receding horizon framework. Secondly, to establish the practical requirements of this type of control by evaluating the sensitivity of the turbine power output to several receding horizon time intervals. Finally, to test and validate experimentally the proposed algorithms in a small-scale PTO test rig. All the experimental tests were performed considering Irregular Wave conditions.
