A dynamic model of the disk drive spindle motor and its applications

A dynamic model of the hard disk-drive spindle motor based on the circuit-field-motion coupled-time-stepping finite-element method is presented. The model provides a basis for determining back electromotive force, inductance, and cogging torque in dynamic operation conditions. The merits of the proposed method are that the estimation of the motor parameters can be obtained, accounting for the saturation effect and other operational conditions, and the computing time for parameters calculation can be reduced. The proposed model can also be used to determine the commutation time, cogging torque, output torque, and radial force, to study the effect of the skewed magnets/slots, and to simulate the starting process and other transient processes.