Analytical modeling of manufacturing imperfections in double rotor axial flux PM machines: Effects on back EMF

© 2016 IEEE. In this paper, a general analytical model is proposed to investigate various eccentricities in double rotor axial flux permanent magnet (DRAFPM) machine, the back electromotive forces (EMFs) is calculated and compared in this paper. At first, the radial and tangential flux density in the air gap under healthy condition is developed via Maxwell's equations and Schwarz-Christoffel mapping. After that, variable air gap length and radii are introduced to calculate the flux density caused by eccentricities. The back EMF at each case is calculated and compared with that in healthy condition. At each section, FEM models are built to validate the analytical model, and the results show that the analytical model predictions agree well with those from the FE results. Finally, the analytical model is verified via experimental results