Cogging torque reduction in Dual-Rotor Permanent Magnet Generator for Direct Coupled Stand-Alone Wind Energy Systems

In a permanent magnet machine cogging torque is produced due to the interaction between the rotor magnets and the slots and teeth of the stator. This paper is a result of an ongoing research work that deals with reduction of cogging torque in dual-rotor radial flux permanent magnet generator (DRFPMG) for direct coupled stand-alone wind energy systems. The DRFPMG is an existing machine design. Two methods are employed to reduce the cogging torque in DRFPMG. The methods used are changing the magnet pole width and changing the slot opening width. Both determination and reduction of cogging torque is carried out by finite element analysis (FEA) using MagNet Software. The cogging torque of DRFPMG has been reduced to a significant level without major change in induced emf. The simulation results are presented.