Influence of winding structure and the effect of MMF harmonics to the spindle motor performance for ultra-high TPI HDD

The technologies for maintaining high recording densities to suppress mechanical vibration and media flutter require advance spindle motor design and technology. To realize multi-magnetic poles with limited stator slots, radial air gap field HDD spindle motor are normally used concentrated winding. Based on different pole/slots combinations, there would be a variety of winding configurations. In this work, detailed analysis is carried out to identify the optimal winding structures of the high speed spindle motor and analyze their effect to the motor performances by using MMF harmonics analysis and FEM. Results are useful in preliminary and final optimal designs of the high speed spindle motors.