AERODYNAMIC AND ELECTROMAGNETIC ANALYSIS OF A VARIABLE ELECTROMOTIVE-FORCE GENERATOR FOR A WIND TURBINE

摘要

A question that usually arises is whether an existing wind turbine with a specified rotor can be modified to expand its operational range and improve the power generation. There are various methods to achieve this goal and one of them can be a modified generator referred to as a variable electromotive-force generator (VEG), where the overlap between the rotor and the stator is made to be adjustable. In this work the possibility of harnessing more wind power via a VEG in areas with large changes in the wind speed from very low to high values throughout a year is investigated theoretically. Aerodynamic and mathematical techniques are used to estimate the generated power of a wind turbine in the low wind speed region, and a combination of electromagnetic and aerodynamics principles are employed to obtain the mathematical model of the VEG with an adjustable overlap between the rotor and the stator. The Neg-Micon wind turbine (NM-72) specifications for a certain site in Thailand are used for the numerical analysis. The results show the possibility of expanding the operational range and increasing the power generation of the studied wind turbine.