Energy yield of two generator systems for small wind turbine application

Abstract

This paper presents the design of an axial flux permanent magnet (AFPM) generator and comparison of cost and energy yield of this generator with an automotive alternator which was adapted for small wind turbine application. The designed AFPM generator is a double-sided (TORUS) machine with air gap winding having 3 coils per pole and one stator disk sandwiched between two external rotor disks. The second generator concept comprises an automotive alternator equipped with a gear system to increase the speed from turbine to alternator. The AFPM generator is directly connected to turbine while a belt drive is used to increase alternator speed to about 3000rpm. Comparison of the two generator systems is made using a 2.8kW, 310rpm wind turbine for a given wind climate. The two generator systems present attractive low-cost options for small scale wind power generation in moderate wind speed areas. Results show that although the automotive alternator concept is a cheaper solution with easily available components, the AFPM generator seems more attractive having high annual energy yield and efficiency.