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.