Research On Axial Flux Generator For Small-Scale Vertical-Axis Wind Power Application

Now, energy sources consumption increasing fast and environment empoison being serious gradually, the development and utilization of new energy and renewable energy are paid great attention by more and more countries. As one of the most matured technologies of new energy industry, wind power has broad commercial prospects. Therefore, wind power is geting more and more attention from goverments and companies all over the world, and wind power technology also becomes a focus of research. Off-grid small wind energy conversion system, with its advantages of high mobility and flexibility, has broad prospects for application not only in road lighting, small power monitoring but also remote areas and household electricity. With the merits of simple structure and large moment of inertia, axial flux permanent magnet (AFPM) generators can be designed into one with the wind turbine. The absence of stator core eliminates the cogging torque and the stator coreloss, so the double-rotor single-stator coreless AFPM wind generator can start at a low torque and operate with high efficiency, and is a most suitable candidate for small vertical-axis wind power systems.As the air gap magnet is axial, the design of disk electric machines is different from ordinary radial flux electric machines. On the basis of introducing the structure of disk electric machines, the electromagnetic formulas are deduced, and then the preliminary design of a300W generator is completed. By finite element analysis (FEA) and variables analysis, the parameters of the disk generator, such as the shape of permanent magnets, the thickness of permanent magnets, the pole arc coefficient, are optimized. The magneto static analysis and the transient analysis are completed using the FEA software Maxwell3D, and the analysis results validate the rationality of the design, there are a lot of difficulties in the manufacture of the disk generator, such as the making of the rotors, the fixation of the PMs and the processing of the coreless stator, etc. This paper makes moulds, summers up the production process, and finally makes the model machine. The performance of the disk generator is tested. The tests show that the generator not only can run smoothly with high output steady, but also has high efficiency. At last a wind power experiment is done for the generator; the experiment shows that the double-rotor single-stator coreless AFPM generator is quite suitable for small vertical-axis wind power systems.