Seagate Technology Incorporated

James Wilford DuLaney

Raye Abdoulie Sosseh

Ryan Todd Lyle

Method and apparatus for accelerating a multi-phase motor having a rotatable rotor are disclosed. A first commutation state in which the rotor resides is identified, after which a Proportional, Integral and Derivative (PID) control routine is executed for closed loop control of an acceleration of the rotor from a stopped position to an intermediate velocity, after which back electromotive force (Bemf) commutation is used to control the motor. The PID control routine utilizes a loop gain value optimized through voltage feedback indicative of a response of windings of the rotor to an application of a drive current across the windings. Based on the voltage feedback a controller programmed with the PID control routine provides an updated commanded current for each successive commutation state of the motor for use by a motor driver circuitry, which drives the motor through each commutation state until attainment of the intermediate velocity.

Closed loop acceleration control for a data storage device motor

Method and apparatus for accelerating a motor to an operational velocity using a continuous sequence of current limit values derived from a plurality of discrete current limit values. Each discrete current limit value establishes a maximum current magnitude for the motor over a plurality of intermediate velocities less than the operational velocity. Each current limit value in the continuous sequence of current limit values has a different magnitude for each different one of the plurality of intermediate velocities. The continuous sequence of current limit values are preferably derived by generating coefficients of a multi-order polynomial curve in relation to the discrete current limit values, and obtaining the continuous sequence of current limit values in relation to said coefficients. Faster acceleration, reduced current spiking and less acoustic noise during motor acceleration are thereby obtained.

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Edmond, OK, United States of America

James Wilford DuLaney