Generator design for vertical axis wind turbine

Abstract

The optimization process for generators are often done for rated speeds and torques. This thesis will discuss and show optimization of a vertical axis wind turbine generator that has a given wind profile. Although the rated power of the turbine is at winds of about 10 m/s, the wind is mostly at 4-6 m/s, thus needing a generator that has high efficiencies also at lower speeds and torques.Vertical axis wind turbine does not use blade pitching as the horizontal ones do and the torque and speed characteristics are therefore a bit different. It is important that the generator has a high efficiency at lower wind speeds. Optimization with different rated speeds where therefore done to ensure that the best generator was found. The final results for the wind turbine QR5, produced by Quiet Revolution, was a generator with rated speed of 260 rpm. All though it was not the one with the highest efficiency it had the highest cost efficiency and gave the greatest profit over 20 years.