Wind tunnel assessment of small direct drive wind turbines with permanent magnets synchronous generators

Abstract

Most of the small wind turbines for battery charging application are direct drive type with permanent magnets synchronous generators. A major problem in designing small direct drive wind turbines is the matching between the power curves of turbine and generator. The maximum power is extracted out from wind and fed into the load only if it is a match between the power curves of turbine rotor and generator. The assessment of the main components performances which contribute to the conversion process, namely turbine and generator, is made in wind tunnel. The experiments described below were carried out on wind turbines with carefully studied blade profile and permanent magnets synchronous generator, designed using a dedicated procedure. The paper describes the experimental layout and the results of the wind tunnel tests of two wind turbines, 250W and 1kW, designed for battery charging. The work has two objectives: measurement of the power curve of the turbine and the performances of the turbine-generator assembly with the load and the verification of the design method for maximum power delivered to the load.