Ring-shaped surface-mounted permanent magnet generators with modular stator for small wind turbines

The work compares the volume, and the copper and iron losses, of three topologies of a modular surface-mounted permanent magnet synchronous generator for a small wind turbine. These are connected to the grid by an AC-to-AC converter, formed from back-to-back PWM inverters. The modular construction reduces the manufacturing complexity since the generator has a ring shape and is installed around the turbine. The use of rare earth (NdFeB) and ferrite permanent magnets is assessed by considering the armature modules. The proposed topologies are evaluated with reference to the permanent magnet type and pole number in order to identify the arrangement that produces the lowest loss. Results show the use of ferrite permanent magnetics can achieve this.