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Delegates are invited to meet and discuss with the poster presenters during the poster presentation sessions between 10:30-11:30 and 16:00-17:00 on Thursday, 19 November 2015.

Lead Session Chair:
Stephan Barth, ForWind - Center for Wind Energy Research, Germany
Rene Aubree ICAM Nantes, France
Co-authors:
Rene Aubree (1) F Pascal Vinot (1) Gilles Payen (3) Yves Tetard (2) Herve Brebion (2) Francois Auger (4) Maeva Sabre (2)
(1) ICAM Nantes, Carquefou, France (2) CSTB, Nantes, France (3) Fondation Ocean Vital, Les sables d'Olonne, France (4) IREENA, Saint Nazaire, France

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Presenter's biography

Biographies are supplied directly by presenters at EWEA 2015 and are published here unedited

Mr. Aubree has been working in the semiconductor industry for almost 25 years. He received the Ph. D degree in electrical engineering from the university of Nantes France in 2014. He is currently a professor in the Icam Nantes electrical engineering department.


Poster

Poster Download poster (12.37 MB)

Abstract

A micro Vertical Axis Wind Turbine (VAWT) tested in the Jules Verne wind tunnel

Introduction

In the context of small wind turbines, our recent work carried out during the Aerojoules project has demonstrated the interest of using a Darrieus shape as an attractive alternative to the traditional horizontal axis wind turbine.

Approach

We have focused our researches on 3 main topics: design of a wind turbine model using static finite element simulations to determine the more efficient profile of the blade, analysis of the static and dynamic phenomena and choice of the good devices, development of an efficient electrical conversion chain. Then the whole conversion chain from wind to battery has been tested and the power coefficient curve has been determined in the CSTB wind tunnel.

Main body of abstract

The blades of the wind turbine have been optimized in a previous project (Aerojoules) and the purpose of this study is the optimization of the mechanical parts and the control of the generator to maximize the amount of energy produced by the wind turbine.
The mechanical components have been designed to reach 4 goals:
• To reduce the friction in the joints, especially using bearings with a reduced friction coefficient and choose the best bearing arrangement. This allows us to obtain more power energy for the basic wind speed (6 to 10m/s) and to ensure that we will be able to obtain energy for small wind speed (4.5 to 6 m/s).
• To design the assembly such that the eigenfrequencies of the wind turbine are not in the bandwidth of the rotation speed (100 – 300 rpm). A Finite element study has been performed to determine the eigenfrequencies. A comparison with the critical speed in the wind tunnel has been dressed and confirm the calculation.
• To simplify the assembly of the different parts to reduce the maintenance time
• To increase the security using a disk-brake
Regarding the electrical side of the project, an original method for the sensorless Maximum Power Point Tracking (MPPT) of a small power wind turbine using a permanent magnet synchronous generator to supply a DC load has been proposed [3]. This method does neither require the knowledge of the wind speed nor the turbine parameters. An analysis of the energy efficiency of the electrical chain shows the interest to maximize the power supplied to the load rather than to track the maximum power at the output of the turbine deduced from its theoretical power coefficient Cp.


Conclusion

The tests of the wind turbine prototype in the CSTB wind tunnel confirm the characteristics we were waiting for: it starts rotating with a 4.2 m/s wind speed and it produces 330 W at 10 m/s of wind speed. The mechanical design of the wind turbine, with the main objective of reducing the friction, has allowed us to maximize the electrical power obtained by the wind turbine. The results obtained in the wind tunnel lead us to continue our analyses and tests in a real outdoor area. The CSTB has an instrumented site dedicated to wind turbine testing. We will monitor atmospheric conditions and wind turbine parameters and simulate an isolated area. The correlation between wind speed and output power will provide information to identify the extremum seeking control parameters used in the MPPT control.


Learning objectives
Maximize the energy the energy extracted from the wind at low wind speed.
Remove the eigenfrequencies from the mechanical bandwidth.
Get a simulation tool to design blades
Provide an innovative sensorless MPPT control.