Patent Document ID: 20130154537
Application ID: 13714822
Patent Flag: 0

Claim One:
1. A motor control apparatus that controls rotation of a rotor of an electric motor powered from an electric power source, the motor control apparatus comprising: an encoder that outputs a pulse signal at predetermined angular intervals in response to the rotation of the rotor of the electric motor; a counter that counts the pulse signal output from the encoder; a learning portion that executes an initial drive learning process, the learning portion executing an initial drive operation to sequentially change an exciting phase of the electric motor using an open loop control after powered from the electric power source, correcting a count value of the counter by calculating a correction value based on a deviation of the exciting phase of the electric motor with respect to the count value of the counter, and learning the correction value in the initial drive learning process; and a controller that executes a normal drive operation to sequentially change the exciting phase of the electric motor based on the count value corrected by the correcting portion such that the rotor is rotated to a target position after the initial drive operation is finished, wherein the learning portion re-executes the initial drive learning process after a predetermined condition is satisfied, when the initial drive learning process is failed.