Tag Archives: Generator

Preliminary Design of Axial Flux Permanent Magnet Machine for Marine Current Turbine


Ju Hyung Kim and B. Sarlioglu – 39th Annual Conference of the IEEE Industrial Electronics Society, IECON 2013, November 2013

Abstract

This paper presents an analytical analysis and application of axial flux permanent magnet machine design to marine current turbine. Marine current is a prominent renewable energy source because of its predictable current profile. Rim-driven, direct-drive type is favorable for the marine current turbine application in terms of maintenance and reliability. The axial flux permanent magnet machine is a candidate machine type that not only reduces machine manufacturing costs, but also achieves high performance. The general sizing equation technique is implemented to produce the machine size. The magnetic flux relationship among air gap, stator yoke, rotor yoke, and permanent magnet is taken into account to calculate core material size of the machine. FEA simulation results are compared with analytical calculations. The proposed machine and the reference machine design results are briefly compared. Moreover, machine cost is estimated based on the volume of the proposed machine.

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Design and Experimental Analysis of AC Linear Generator with Halbach PM Arrays for Direct-Drive Wave Energy Conversion


Zhang, J; Yu, H.; Chen, Q.; Hu, M.; Huang, L.; and Liu, Q. – IEEE Transactions on Applied Superconductivity, November 2013

Abstract

To convert wave energy into more suitable forms efficiently, a single-phase permanent magnet (PM) AC linear generator directly coupled to wave energy conversion is presented in this paper. Magnetic field performance of Halbach PM arrays is compared with that of radially magnetized (R-magnetized) structure. Then, the change of parameters in the geometry of slot and Halbach PM arrays’ effect on the electromagnetic properties of the generator are investigated, and the optimization design guides are established for key design parameters. Finally, the simulation results are compared with test results of the prototype in wave energy conversion experimental system. Due to test and theory analysis results of prototype concordant with the Finite element analysis results, the proposed model and analysis method are correct and meet the requirements of direct-drive wave energy conversion system.

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Hydro-Kinetic Energy Conversion: Resource and Technology


M. Grabbe – PhD Dissertation, Uppsala University, April, 2013

Abstract

The kinetic energy present in tidal currents and other water courses has long been appreciated as a vast resource of renewable energy. The work presented in this doctoral thesis is devoted to both the characteristics of the hydro-kinetic resource and the technology for energy conversion. An assessment of the tidal energy resource in Norwegian waters has been carried out based on available data in pilot books. More than 100 sites have been identified as interesting with a total estimated theoretical resource—i.e. the kinetic energy in the undisturbed flow—in the range of 17 TWh. A second study was performed to analyse the velocity distributions presented by tidal currents, regulated rivers and unregulated rivers. The focus is on the possible degree of utilization (or capacity factor), the fraction of converted energy and the ratio of maximum to rated velocity, all of which are believed to be important characteristics of the resource affecting the economic viability of a hydro-kinetic energy converter.

The concept for hydro-kinetic energy conversion studied in this thesis comprises a vertical axis turbine coupled to a directly driven permanent magnet generator. One such cable wound laboratory generator has been constructed and an experimental setup for deployment in the river Dalälven has been finalized as part of this thesis work. It has been shown, through simulations and experiments, that the generator design at hand can meet the system requirements in the expected range of operation. Experience from winding the prototype generators suggests that improvements of the stator slot geometry can be implemented and, according to simulations, decrease the stator weight by 11% and decrease the load angle by 17%. The decrease in load angle opens the possibility to reduce the amount of permanent magnetic material in the design.

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Power system stability enhancement with an integrated offshore wind farm and marine-current farm using a STATCOM


D-N Truong – 2012 IEEE Asia Pacific Conference on Circuits and Systems (APCCAS) – December, 2012

Abstract

This paper presents the simulation results of using a static synchronous compensator (STATCOM) to achieve damping improvement of a synchronous generator (SG)-based one-machine infinite-bus (OMIB) system with an integrated offshore wind farm (OWF) and marine-current farm (MCF). The operating performance of the studied OWF is simulated by an equivalent permanent-magnet generator (PMG) driven by an equivalent wind turbine (WT). An equivalent squirrel-cage rotor induction generator (IG) driven by an equivalent marine-current turbine (MCT) is used to simulate the operating characteristics of the MCF. A damping controller of the STATCOM is designed by using modal control theory to contribute adequate damping characteristics to the dominant modes of the studied OMIB system under various operating conditions. A time-domain scheme based on a nonlinear system model subject to three-phase short-circuit fault at the power grid is utilized to examine the effectiveness of the proposed control scheme. It can be concluded from the simulation results that the proposed STATCOM joined with the modal-control designed damping controller is capable of improving the stability of the studied OMIB system subject to severe disturbance.

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THOR’s Power Method for Hydrokinetic Devices


J.T. Hunt and J. Rumker – Technical Report submitted to DOE EERE Wind & Water Power Program, August, 2012

Abstract
Ocean current energy represents a vast untapped source of renewable energy that exists on the outer continental shelf areas of the 5 major continents. Ocean currents are unidirectional in nature and are perpetuated by thermal and salintiy sea gradients, as well as coriolis forces imparted from the earth’s rotation. This report details THORs Power Method, a breakthrough power control method that can provide dramatic increases to the capacity factor over and above existing marine hydrokinetic (MHK) devices employed in the extraction of energy from ocean currents. THORs Power Method represents a constant speed, variable depth operational method that continually locates the ocean current turbine at a depth at which the rated power of the generator is routinely achieved. Variable depth operation is achieved by using various vertical force effectors, including ballast tanks for variable weight, a hydrodynamic wing for variable lift or down force and drag flaps for variable vehicle drag forces.

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A novel linear switch reluctance generator system


Y Pu, S Zhou, J Gu, H Chen, C Zhang – 2012 IEEE International Conference on Automation and Logistics (ICAL), August, 2012

Abstract

A novel linear generator system prototype has been developed to harness tidal and wave energy. The point absorber is designed to extract energy from ocean waves. The main circuit of power converter and control system based on DSP are designed. The experimental study has been carried out on the three-phase 6/4 structure linear switched reluctance generator. The scotch yoke is designed to convert the motor rotational motion to linear motion, which mimics the tidal motion. Simulation and experimental results verified the design.

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Neural control for voltage dips ride-through of oscillating water column-based wave energy converter equipped with doubly-fed induction generator


M Alberdi, M Amundarain, A Garrido, I Garrido – Renewable Energy, December 2012

Highlights
The most demanded skill during voltage drops is a fault-ride-through capability. ► The innovative aspect exploited in this paper is the application of a neural control. ► The controller changes the references according to the pressure drop and voltage dip. ► The neural controller achieves the uninterrupted operation of the wave energy plant.

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Efficiency improvement of a tidal current turbine utilizing a larger area of channel


KP Kim, MR Ahmed, YH Lee – Renewable Energy, December 2012

Highlights
► Two cases of a single turbine in a channel and a number of turbines are simulated. ► In the case of a single turbine the velocity of water entering the turbine is small. ► The velocity of water increases for the case of multiple turbines. ► The power output and coefficient of power increase significantly for this case.

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Specialized Power-Electronic Apparatus for Harnessing Electrical Power from Kinetic Hydropower Plants


Farid Mosallat – PhD Dissertation, University of Manitoba, July 2012

Abstract

This thesis introduces a power electronic interface for a kinetic hydropower generation platform that enables extraction of electric power from a free-flowing water source such as a river or a stream. Water currents are of fluctuating nature and hence, a power interface is required to provide regulated voltage for the load from this resource.

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Evaluation of Ocean-Energy Conversion Based on Linear Generator Concepts


MA Stelzer – July 2012

Summary
As the world continues to demand greater productivity and lifestyle enrichment through technological advancements, the demand for electrical power is predicted to escalate dramatically. Thus far, this increased demand has been primarily supplied from fossil fueled plants. Unfortunately, the burning of fossil fuels produce harmful carbon dioxide pollution as a by-product. It has been hypothesized that unless a clean, renewable, and efficient alternate source of energy is found soon, the world may either exhaust its supplies of energy-producing materials or drastically degrade its environment. However, motions that occur naturally, such as ocean waves, can play a significant role in generating environmentally safe and economically viable energy for human utilization. The focus of this work predicts the electrical power generation capabilities from a seabed mounted linear generator tethered to a floating buoy heaving under the influence of passing ocean surface waves. Mathematical models are introduced which simulate the oceans’ surface conditions under both the regular (basic) and irregular (natural) wave regimes, the heave (vertical displacement) response for a floating buoy, and the resulting electrical output parameters of the linear generator. Within these models, various physical and electrical parameters are altered in an attempt to generate a greater output power for a given sea state condition, making the Wave Energy Converter (WEC) more efficient. It is shown theoretically that the buoy can be designed to have a greater heave response than that of the height of a passing wave resulting in an increase in generated power from the linear generator.

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