Computation of Armature Reaction Field and Full-Load Characteristics of an Axial flux Surface Mounted PM Machine Using a New Analytical Approach

In recent years axial flux permanent magnet (AFPM) machines have found industrial applications because of such characteristics as high power density, compact structure and disc-like shape. Like other electrical machines, prediction of flux density distribution in the air gap of AFPM is essential. In this paper, an analytical method for calculation of air gap flux density caused by armature reaction is presented. The solution is based on Maxwell's equations. Separation of variables method is applied to field equations and 2D distribution of magnetic flux density in the air gap calculated in term of Fourier series. The 2-D distribution of three-phase armature winding is modeled exactly. Finally the calculated axial and tangential field waveforms are compared with corresponding 3-D finite element analysis results.