Optimisation tools for large permanent magnet generators for direct drive wind turbines

Zavvos, A.; McDonald, Alasdair; Mueller, Markus

doi:10.1049/iet-rpg.2012.0135

Cited by 32 publications

(27 citation statements)

References 15 publications

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“…where FCR represents the fixed charge rate given in Table I, ICC is the initial capital cost of the turbine and AOM is the annual operation and maintenance cost given in Table I (assumed to be fixed for different machine design). The initial capital cost can be calculated as, = gact + gstr + tower + sf + fan + hex + rt (13) where Cgact is the generator active materials cost, Cgstr is the generator structural materials cost, Ctower is the tower cost, Csf is the substructure and foundation cost, Chex is the cost of heat exchanger and Crt is the rest of the turbine cost given in Table I.…”

Section: ) Objective Functionsmentioning

confidence: 99%

“…Different authors have approached different optimization methods with different objective functions to minimize the generator cost of active materials, cost of structural materials, losses, masses and maximize the efficiency and annual energy productions [5], [10][11][12][13]. A hybrid algorithm combining T Genetic Algorithms (GA) with Pattern Search (PS) is used in [9].…”

Section: Introductionmentioning

confidence: 99%

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Optimization of Offshore Direct Drive Wind Turbine Generators With Consideration of Permanent Magnet Grade and Temperature

Bhuiyan

McDonald

2019

IEEE Trans. Energy Convers.

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In this paper, the main objective is to optimize permanent magnet synchronous generators for offshore direct drive wind turbine, examining the best choice of magnet grades, BHmax and working temperature. A surface-mounted Nd-Fe-B generator is designed electromagnetically and structurally and optimized for different rated powers of 6, 8 and 10 MW. The results show that the cost of energy decreases as the wind turbine's rated power increases. Further optimizations were carried out using different neodymium magnet grades and it was found that the higher magnet grades produce a lower cost of energy. In addition, steps were taken to estimate the effect of magnet temperature. A detailed thermal model is used to calculate the cooling airflow requirements to bring the magnet operating temperature from 120°C to 80°C. Allowing the use of cheaper temperature grades of magnets, the additional cooling reduces winding losses and improves the effective BHmax of the magnets. IndexTerms-Cooling system, cost of energy, magnet grade, optimization, permanent magnet generator, thermal model, wind turbine. N. A. Bhuiyan is with ASTUTE, College of Engineering, Swansea University, Swansea SA1 8EN and A. McDonald is with the Institute

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Section: ) Objective Functionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimization of Offshore Direct Drive Wind Turbine Generators With Consideration of Permanent Magnet Grade and Temperature

Bhuiyan

McDonald

2019

IEEE Trans. Energy Convers.

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“…The model was constrained at the shaft and a mesh size of 100mm was utilised [5]. The structures were analysed for mode 1 assuming a deformation of = 0.0027m and = 0.0015m in a 5mm air-gap.…”

Section: Structural Stiffness Finite Element Analysismentioning

confidence: 99%

Structural Analysis and Characterization of Radial Flux PM Generators for Direct-Drive Wind Turbines

Jaen-Sola¹,

McDonald²

2014

3rd Renewable Power Generation Conference (RPG 2014)

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Wind turbine direct-drive generator structures are analysed in order to optimise and reduce mass. A method for modelling key stiffness parameters including a magnetic air-gap stiffness is outlined. Different approaches are used to parametrically calculate structural stiffness and mass. Finite element and analytical techniques are used to model mode 0 and mode 1 deflections and these can be used along with parametric models of electromagnetically active material.

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“…Bazzo et al outlined some objective functions to minimize costs and maximize efficiency which included minimizing active and structural materials cost and minimizing cost of losses to get maximum return of investment [9]. Zavvos et al offered an analytical tool that minimizes the generators mass or cost by optimizing both the electromagnetic and structural design at the same time [10]. Wu et al also outlined the optimization of generator rotor structure for minimum generator mass where deflections were constrained [11].…”

Section: Introductionmentioning

confidence: 99%

“…With this technique a global search is carried out first using the GA and an intermediate set of solutions are found after a few generations. These solutions are used as initial parameters for Most of the generator models in [4][5][6][7][8][9][10][11] focus on the active material and losses but do not consider the generator structure in detail. McDonald showed that the structural mass of a 5 MW permanent magnet direct drive generator can be more than 80% of its total mass [16].…”

Section: Introductionmentioning

confidence: 99%

On the Optimization of Generators for Offshore Direct Drive Wind Turbines

McDonald

Bhuiyan

2017

IEEE Trans. Energy Convers.

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The Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output.1 Abstract-The objective of this paper is to optimize direct drive permanent magnet synchronous generators for offshore direct drive wind turbines in order to reduce the cost of energy. A 6MW wind turbine design is assumed and parametric electromagnetic and structural generator models are introduced for a surface-mounted magnet generator topology (using magnets with high BHmax) and a flux-concentrating variant (using magnets with lower BHmax). These are optimized using a hybrid Genetic Algorithm and Pattern Search process and the results show that the surface-mounted permanent magnet generator produces the lower cost of energy. The choice of objective function is addressed and it is found that a simplified metric incorporating generator cost and losses proxy produces similar designs to a full cost of energy calculation. Further steps to improve the quality of the model include the effect of generator mass on the design and cost of the turbine tower and foundation, which can add €0.4m to the turbine cost. Further optimizations are carried out to show the impacts of magnetic material costs (doubling this leads to a €1.1/MWh increase in cost of energy) and generator diameter limits (increasing the upper limit from 6m to 8m leads to a 0.9% drop in cost of energy) have on the choice of optimum independent variables.Index Terms-Cost of energy, direct drive wind turbine, optimization, permanent magnet generator, structural model, tower and foundation. I. INTRODUCTIONgrowing proportion of offshore wind turbine designs are now based on directly driven permanent magnet synchronous generators. Direct drive machines can offer higher reliability and reduced maintenance cost because of the omission of the gearbox from the drive train [1]. Some of the downsides of these generators include their large size (due to the high torque rating), requirements for large quantities of rare earth permanent magnets and the significant generator structures required to maintain the small air-gap clearance against the large attraction forces between the rotor and the stator [2]. The generator designer needs to deliver a number of performance characteristics including high efficiency, low power losses at part load, high availability, low machine mass, reduced volume and lower material and manufacturing costs. Normally the designers employ some element of optimization to achieve the best balance of these aspects [3].The main purpose of this paper is to examine the process of optimizing large, low speed generators for offshore direct drive wind turbines, exploring the different objective functions that a A. McDonald and N. A. Bhuiyan are with the Institute of Energy and Environment, Department of Electronic and Electri...

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Optimisation tools for large permanent magnet generators for direct drive wind turbines

Cited by 32 publications

References 15 publications

Optimization of Offshore Direct Drive Wind Turbine Generators With Consideration of Permanent Magnet Grade and Temperature

Optimization of Offshore Direct Drive Wind Turbine Generators With Consideration of Permanent Magnet Grade and Temperature

Structural Analysis and Characterization of Radial Flux PM Generators for Direct-Drive Wind Turbines

On the Optimization of Generators for Offshore Direct Drive Wind Turbines

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