Patent ID: 7786687

Claim:
A method for controlling an electric motor that includes a plurality of coils providing phases of the motor, said method comprising: providing actual position signals indicative of the actual position of the motor; providing a commanded position signal of a desired position of the motor; determining a position error signal between the commanded position signal and the actual position signals; operating the electric motor in a commutation hold mode when the absolute value of the position error signal is less than a first predetermined threshold by sending signals to coils of the motor to prevent the motor from rotating; operating the electric motor in a commutation normal mode when the absolute value of the position error signal is greater than a second predetermined threshold that is greater than the first predetermined threshold; and operating the electric motor in an angle step mode if the position error signal is between an intermediate threshold and the second threshold where the angle step mode provides a signal to the motor to move the motor forward or backward a predetermined number of motor steps.