A Small Wind-Electric System Based on an Improved Version of the ITDG Axial Flux Permanent Magnet Generator

Probst, Oliver; González, Adrián Martínez; Roidl, Matthias; Llamas, Armando

doi:10.1260/030952406779502641

Cited by 3 publications

(2 citation statements)

References 5 publications

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“…[1,19]) combined with a blade-element momentum (BEM) code [1,20] is capable of accurately predicting the field performance for nonfurling conditions. (2) To show experimentally how the aerodynamic field performance can be effectively manipulated by changing the load conditions.…”

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confidence: 99%

Experimental study of a small wind turbine for low- and medium-wind regimes

Elizondo

Martínez²,

Probst

2009

Int. J. Energy Res.

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SUMMARYThe results of an experimental assessment of a small prototype battery charging wind turbine designed for low-and medium-wind regimes are presented. The turbine is based on a newly designed axial flow permanent magnet synchronous generator and a three-bladed rotor with variable twist and taper blades. Overspeed control is performed by a furling mechanism. The turbine has the unique feature of being capable of operating at either 12, 24 or 48 V system voltage, requiring no load control in any case. In the 48 V configuration, the system is capable of providing 2 kWh day À1for an average wind speed as low as 3.5 m s À1 and an air density of 85% of the standard pressure and temperature value. The experimental assessment has been conducted under field conditions with the turbine mounted on a 20 m guy-wired tubular tower. The experimental power curves are shown to be in good agreement with a detailed aerodynamical and electromechanical model of the turbine for non-furling conditions and for wind speeds above the theoretical cut-in speed. In the case of the rapidly spinning load configurations, a finite power production at wind speeds below the theoretical cut-in speed can be observed, which can be explained in terms of inertia effects. During the measurement campaigns with high loads, we were able to observe bifurcations of the power curve, which can be explained in terms of instabilities arising in situations of transition from attached to separated flow. A full experimental C p (l)-curve has been constructed by operating the turbine under different load conditions and the findings are in good agreement with a variable Reynolds-number blade-element momentum model. The three proposed system configurations have been found to operate with a high aerodynamic efficiency with typical values of the power coefficient in the 0.40-0.45 range.

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confidence: 99%

Experimental study of a small wind turbine for low- and medium-wind regimes

Elizondo

Martínez²,

Probst

2009

Int. J. Energy Res.

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“…The EMP6354-KV200 electric generator was characterized following the theoretical and experimental procedures proposed in [29,39,40], where a set of characteristic curves of mechanical torque, rectified voltage, and rectified current as a function of both the rotational speed ( [rpm]) and the effective electric load ( Load [Ω]) were obtained by means of a customized electromechanical test bench. The electromechanical characterization allowed determining the aerodynamic efficiency of the SWT at any operational condition by comparing the available free-stream power and the mechanical power delivered to the electric generator.…”

Section: Small Wind Turbine Prototypementioning

confidence: 99%

A Hybrid Metaheuristic-Based Approach for the Aerodynamic Optimization of Small Hybrid Wind Turbine Rotors

Herbert-Acero

Martínez-Lauranchet

Probst

et al. 2014

Mathematical Problems in Engineering

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This work presents a novel framework for the aerodynamic design and optimization of blades for small horizontal axis wind turbines (WT). The framework is based on a state-of-the-art blade element momentum model, which is complemented with the XFOIL 6.96 software in order to provide an estimate of the sectional blade aerodynamics. The framework considers an innovative nested-hybrid solution procedure based on two metaheuristics, the virtual gene genetic algorithm and the simulated annealing algorithm, to provide a near-optimal solution to the problem. The objective of the study is to maximize the aerodynamic efficiency of small WT (SWT) rotors for a wide range of operational conditions. The design variables are (1) the airfoil shape at the different blade span positions and the radial variation of the geometrical variables of (2) chord length, (3) twist angle, and (4) thickness along the blade span. A wind tunnel validation study of optimized rotors based on the NACA 4-digit airfoil series is presented. Based on the experimental data, improvements in terms of the aerodynamic efficiency, the cut-in wind speed, and the amount of material used during the manufacturing process were achieved. Recommendations for the aerodynamic design of SWT rotors are provided based on field experience.

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