Analysis and design of axial flux permanent magnet wind generator system for direct battery charging applications
In this study the focus is on the implementation of a coreless axial ux permanent magnet (AFPM) generator for use in a wind generator application with direct battery charging. The wind generator power system is analysed and discussed. The common concerns with AFPM wind generators in recti er-fed direct battery charging applications, such as maximum power point matching and acoustic noise emission, are discussed. In this study the AFPM wind generator is theoretically analysed and the different winding topologies for this type of machine are evaluated. This evaluation is based on a theoretical analysis and con rmed by nite element analysis and practical measurements. It is shown that an AFPM machine equipped with nonoverlapping windings can give a similar performance to that of normal overlapping windings, while using less copper. It is shown in this thesis that the coreless AFPM generator has a relatively low internal phase synchronous inductance resulting in severe problems with regard to maximum power matching and noise. A method is proposed and in detail analysed in this thesis whereby better power point matching is achieved and near-sinusoidal current is obtained using AFPM generators in direct battery charging wind energy systems. The wind generator system's performance is verified with a SimplorerTM simulation package and practical measurements. The calculations from theoretically derived equations are in good agreement with finite element and measured results.