Control strategies for hard-disk spindle drives

This paper describes the development of a control strategy for high-torque spindle motor drives used in hard-disk drives (HDDs). It uses the per-phase torque characteristics of the motor, which is termed the motor identity, for the optimization of the input current to achieve high efficiency and optimal torque production. This control strategy is described as `identity control´. A self-starting technique is also developed to start the spindle motor and to operate the motor without sensors. This paper also discusses the implementation of a zero voltage switching quasi-resonant power converter (ZVS-QRC) to achieve high power efficiency by minimizing switching losses in the power devices. Simulation and experimental results are presented and a comparison is made for the identity controlled spindle drive and a BLDCM controlled spindle drive