No-load magnetic field analysis of double stator double Rotor radial flux permanent magnet generator for low power wind turbines

In this paper instantaneous no-load magnetic field analysis of a double stator double rotor radial flux permanent magnet [DSDR RFPM] machine has been presented. To design a machine optimally, it is important to know completely the magnetic flux densities in the different parts of the machine. Flux density at the stator surface obtained from the no-load magnetic field analysis is used to calculate the open-circuit voltage of the machine. The DSDR RFPM machine has two active stator surfaces, flux density patterns on both of these surfaces have been obtained by the analysis presented in this paper. The magnetic flux density distribution in the stator region is the most important parameter while designing the DSDR RFPM machine. Using the analysis presented in this paper, variation of magnetic field in the stator region in r-θ plane have been predicted. Results obtained by the analytical techniques have been verified with the results of finite element analysis obtained by using Ansoft-Maxwell package. DSDR RFPM machine has high torque/power density[Nm/cm3 or kW/cm3]. Thus the double stator double rotor radial flux permanent magnet [DSDR RFPM] machine as a generator for low power wind turbines is analyzed in this paper.