Steady Grid Power From Wave Energy
TL;DR: In this article, a new scheme for reducing the fluctuations in power to a grid-connected wave energy plant is proposed, which achieves this by physically decoupling the turbine from the induction generator and by using a secondary rotating scheme.
Abstract: A new scheme for reducing the fluctuations in power to a grid-connected wave energy plant is proposed. It achieves this by physically decoupling the turbine from the induction generator and by using a secondary rotating scheme. Experimental results from a wave energy plant are reported, which led to the solution.
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TL;DR: In this paper, the authors presented both time-domain and frequency-domain simulated results of a novel marine hybrid renewable-energy power generation/energy storage system (PG/ESS) feeding isolated loads through an highvoltage direct current (HVDC) link.
84 citations
Cites background or methods from "Steady Grid Power From Wave Energy"
...The employed parameters of the studied PG/ESS are listed in Table 1. The model parameters are determined by the cited papers [1,12, 13 ,16,22,23,26] and the stability reference book [25]....
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...2.1. Characteristic of WETG’s output power [12, 13 ]...
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TL;DR: In this paper, an oscillating water column-based wave energy conversion plant is modeled and controlled by means of two complementary control strategies in order to improve the conversion of wave energy into electric power.
Abstract: In this paper, an oscillating water column-based wave energy conversion plant is modeled and controlled by means of two complementary control strategies in order to improve the conversion of wave energy into electric power. This wave power generation system consists of a capture chamber, a Wells turbine, and an induction generator. The improvement relays on the implementation of a control scheme that combines two different control methods: a rotational speed control and an airflow control implemented by means of a throttle valve in series with the turbine. The use of rotational speed control provides a fast way to react to the abrupt and short changes in the turbine speed, ensuring that the average power of the generator is adequately adjusted according to the incident wave power level. Besides, a throttle-valve is used to control the flow through the turbine so as to increase the amount of energy produced, particularly at the higher incident wave power levels. These two control strategies complement each other, maximizing and improving the quality of supply by controlling and smoothing the generated power for different scenarios of wave oscillations, variations of wave grouping, and changes in the sea state.
83 citations
TL;DR: In this paper, the suitability or otherwise of the various generator options in the offshore marine environment is examined in detail, with consideration being given to the impact of speed control on the energy output.
Abstract: In the field of wind energy, electrical generator solutions have converged on a small number of technologies for specific technical and economic reasons. This paper investigates whether a similar rationale exists within the field of oscillating water column, wave energy converters. The suitability or otherwise of the various generator options in the offshore marine environment is examined in detail. Each generator configuration is then modeled and the annual energy output for a typical wave climate assessed with consideration being given to the impact of speed control on the energy output. Finally, some conclusions are drawn regarding the relative suitability of the different generator options.
74 citations
TL;DR: An adaptive control strategy including a reactive component is proposed, whose goal is to improve the overall system performance when the WEC is already operative in the sea, and its effectiveness in increasing the average power extraction while respecting the PTO peak power constraint is proved.
Abstract: In wave energy converters (WECs), the maximum power extraction would be achievable at the expense of a very high rating of the electric and power electronics equipment. The goal of this paper is to show how a convenient tradeoff between high-power extraction and viable electrical device rating can be achieved by a proper choice of the WEC control strategy. Referring to a direct coupled point absorber in heave operating in regular waves, it will be analytically shown how most common control techniques impact on both the power performance and the power takeoff (PTO) rating. Thus, a tool that can assist in the preliminary PTO sizing by taking into account the main constraints imposed by the application is obtained. Following, an adaptive control strategy including a reactive component is proposed, whose goal is to improve the overall system performance when the WEC is already operative in the sea. Its effectiveness in increasing the average power extraction while respecting the PTO peak power constraint is proved by computer simulations in both regular and irregular waves, and specific analyses also including the PTO force/torque limitation are finally developed.
69 citations
Cites methods from "Steady Grid Power From Wave Energy"
...This parameter is suitable to cope with systems of different types [20], [27], and it represents an effective indicator for several issues, from the PTO design to the WEC grid connection [28], [29]....
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TL;DR: In this article, a review of wave energy converter (WEC) devices is presented from a system-wide perspective, from the sea waves to the grid connection, focusing on a specific aspect of WEC.
Abstract: Ocean waves are a huge largely unexploited energy resource, and the potential for extracting energy from waves is great. Research in this area is driven by the need to meet renewable-energy targets, but it is relatively immature compared to other renewable-energy technologies. This review introduces some device types that represent the state of the art of oscillating water column technology, a kind of wave energy converter (WEC). Unlike other works in literature, typically limited to specific aspects of WECs, in this paper, a system-wide perspective will be pursued, from the sea waves to the grid connection.
62 citations
References
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Book•
26 Sep 2003
TL;DR: In this paper, the potential of using the power generated by waves as a natural energy resource and considering the power transfer systems needed to do this, and looks at the environmental impacts.
Abstract: Wave energy, together with other renewable energy resources is expected to provide a small but significant proportion of future energy requirements without adding to pollution and global warming. This practical and concise reference considers alternative application methods, explains the concepts behind wave energy conversion and investigates wave power activities across the globe. It explores the potential of using the power generated by waves as a natural energy resource and considers the power transfer systems needed to do this, and looks at the environmental impacts.
96 citations
15 May 2005
TL;DR: In this article, the authors investigated on the reduction of fluctuations in power generated from a prototype wave energy plant, installed as a part of the on-going Indian wave energy programme, when operated on grid connected mode.
Abstract: This paper investigates on the reduction of fluctuations in power generated from a prototype wave energy plant, installed as a part of the on-going Indian wave energy programme, when operated on grid connected mode. The plant, employing an impulse turbine for conversion of differential pressure due to the oscillating water column (OWC) into mechanical shaft power, typically shows a peak to average power ratio of 4.5 to 5.0, which is unacceptable to be readily exported to power grid. A novel method of decoupling the energy storage, by addition of one more energy conversion stage, is tried out. Steady-state based MATLAB - Simulink model and laboratory prototype implementation are carried out and the results are reported. It is seen that the ratio of peak to average power can be brought down to about 1.25, thereby improving the acceptability of power generation from the ocean waves
15 citations
"Steady Grid Power From Wave Energy" refers background or methods in this paper
...The complete mathematical modeling and experimental results validating the method are discussed in [6]....
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...Details of the turbines and machine details are taken from [4]–[6]....
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