Performance Analysis of a Direct Drive Permanent Magnet Generator for Small Wind Energy Applications

This paper describes the performance and analysis of a direct drive Axial Flux Permanent Magnet (AFPM) generator developed for small scale vertical axis wind turbine (VAWT). The generator has been designed for ease of manufacture so that it can be made in small workshops with limited electrical engineering knowledge. The generator has also been designed with large number of poles to increase its efficiency at low wind speeds. The resulting increase in weight is of less concern since its application is for a VAWT. For this reason the generator is also designed to have no cogging torque by employing the use of a core-less (air-cored) stator. The generator efficiency is high with typical efficiency values of between 75-89% from a speed of about 100 runs per minute (RPM)