Design And Characteristic Analysis Of Axial Flux Coreless Permanent Magnet Synchronous Generator

Wind energy gets the more and more favour of people as a kind of clean energy. Wind energy has the advantages of renewable, environmental protection and pure. Therefore, in recent years, wind power has received great attention from all over the world. And the installed capacity of wind power generation grows rapidly. The axial flux coreless permanent magnet synchronous generator has a compact structure, high power density. Because of the advantages of small volume and light weight, it is very suitable for wind turbine generators. A single stator double rotors axial flux coreless permanent magnet synchronous generator(AFCLPMSG) for whose power is 3 kW is designed for the direct drive wind power system.Four topology structures of axial flux permanent magnet machines are introduced in this paper. The problem of slot-pole combination is study in this paper because the non-overlapping concentrated coil winding is adopted in the machine. The characteristics of magnetic circuit and the distribution of magnetic flux leakage are studide in AFCLPMSG. The design of the permanent magnet poles and the winding are researched detailedly.In this paper, the two methods for no-load electromotive force(EMF) harmonic suppression of AFCLPMSG are analyzed. One is using the sine shape permanent magnet, another one is using Response Surface Methodology to make an optimization design of the machine. In the first scheme, the finite element method(FEM) models are established. Then, the the excitation magnetic field, the effect of pole-arc coefficient on air gap flux density and the no-load EMF harmonic suppression are studied and analysis. In the second scheme, the dosage of permanent magnet and the area of coil-side section are set constant firstly. The pole-arc coefficient and the width of coil-side section are regarded as variable. The maximum of the no-load EMF amplitude and the minimum of the total harmonic distortion(THD) of the no-load EMF are regarded as the final goals. The relevant FEM models are established and calculation. Finally, the most optimal parameters of the machine’s electromagnetic design to reduce the no-load EMF harmonic content of the generator are obtained. In the firs scheme, the harmonic content of air gap flux density is lower and the dosage of permanent magnets is much less, but the processing technic of sine shape permanent magnet is difficult. The second scheme which still adopts rectangular permanent magnet, can decrease the difficulty of the processing technic of permanent magnet. But the second scheme requires establishing a number of finite element models. Therefore, this paper has certain research value.