Optimal drive and machine sizing for a self starting, vertical axis, low power wind generator

This paper presents a comparison of different design choices in small wind power systems design. A vertical axis wind turbine is considered,to take advantage of the fact that it is omni-directional, i.e. it can accept wind from any direction. The vertical axis turbine that has been used is a type of straight-bladed Darrieus turbine coupled with a Savonius turbine, in order to built a self starting turbine. To chose the electric generator with its drive, an economic analysis is carried out on the basis of generator, power converter and mechanical system costs. The optimal ratings are found on the basis of the maximum profit over payback time. An Interior Permanent Magnet (IPM) generator and a Surface Permanent Magnet (SPM) generator are compared. The IPM generator can be driven in the flux weakening region, exploiting higher turbine rotation speeds. The paper shows that economic advantages are obtained using an IPM generator, optimized together with the power converter.