Design on Permanent Magnet Structure of Radial Flux Permanent Magnet Generator for Cogging Torque Reduction and Low Torque Ripple

Cogging torque is important factor of a permanent magnet generator because cogging torque affects cut-in wind speed and produces torque ripple, mechanical vibration and noise on wind turbine. In this paper, the design for cogging torque reduction and low torque ripple of outer rotor radial flux permanent magnet generator has been proposed. To reduce cogging torque and torque ripple, pole arc ratio and permanent magnet structure was designed.