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Data storage apparatus, rotation control apparatus, and rotation control method

  • US 7,006,321 B2
  • Filed: 04/01/2003
  • Issued: 02/28/2006
  • Est. Priority Date: 04/04/2002
  • Status: Expired due to Term
First Claim
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1. An apparatus for controlling the rotational speed of a motor, comprising:

  • a motor; and

    a processing system coupled to the motor, wherein the processing system is configured to perform the following operations;

    inputting a representation of a first output pulse and a representation of a successive second output pulse from the motor;

    measuring a first time interval between the first output pulse and the second output pulse;

    calculating a difference between the first measured time interval and a first target time;

    calculating a representation of a first motor drive current, wherein the first motor drive current is a function of the difference between the first measured time interval and the first target time; and

    calculating a second target time that is a function of the first motor drive current, wherein the second target time is designated sn+1 and is calculated in accordance with the following equations;


    pn+1=2 cos(π

    /3)pn

    p
    n−

    1
    +un

    u
    n−

    1

    qn+1=2 cos(π



    )qn

    q
    n−

    1
    +un

    u
    n−

    1

    rn+1=−

    r
    n+un

    u
    n−

    1

    sn+1=k1pn+1+k2pn+k3qn+1+k4qn+k5rn+1+ttarget.

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