Developing the full-field wind electric generator

Abstract

A conventional wind electric generator generally works with a fixed normal rated power (NRP). Moreover, a gearbox for providing such generator the quasi-constant rotational speed to reach its maximum working efficiency is required. It is well known, an electric generator with large NRP also receives relatively small working efficiency while the input power is too small due to it needs gearbox with relatively larger speed ratio to reach the required rotational speed. In general, the larger the speed ratio of gearbox, the larger the transmission loss. In other words, if the mechanical resistance is considered, the conventional wind electric generator actually loses a lot of energy in the slow wind speed field. To avoid the use of gearbox with large speed ratio in the slow wind speed field, a special generator with changeable NRP should be used. This work presents a special wind electric generator using the multi-layer magnetic cutting electric generator, which effectively works in full wind field with the help of the changeable NRP and is already patented by our CCT laboratory. The developed multi-layer magnetic cutting electric generator is the so-called disk or axial flux permanent magnet electric generator with multi-layer structure, which is mainly composed of the rotational axis, the rotational magnet frameworks, and the fixed electric coil frameworks. In process, the numbers of the active fixed electric coil frameworks are changeable due to the different numbers of the active fixed electric coil frameworks has the different NRP. In other words, the developed multi-layer magnetic cutting electric generator can automatically adjust its NRP to match various wind speeds and always reach the maximum working efficiency in the full wind field. The results show that the total working efficiency of the developed full-field wind electric generator has increased ca. 3%.