Apparatus for reliably activating sensorless and brushless DC motor

A sensorless and brushless DC motor control apparatus comprising:

• a sensorless and brushless DC motor having a rotor and a plurality of phase coils;
• excitation means for exciting a pair of phase coils from the plurality of phase coils to rotate the rotor;
• detection means for detecting a magnetic pole position of the rotor from a back electromotive force produced in the excited phase coils;
• and
• control means for controlling the excitation means in accordance with the detected magnetic pole position, and
• wherein at activation of the sensorless and brushless DC motor, the control means controls the excitation means to excite one pair of phase coils to rotate the rotor and then to excite another pair of phase coils to position the magnetic pole position in another pair of phase coils, and the control means determines whether or not the rotor vibrates in accordance with the detected magnetic pole position when the rotor starts to rotate and controls the excitation means to excite a desired pair of phase coils outside another pair of phase coils when the rotor does not vibrate.

A sensorless and brushless DC motor control apparatus comprising:

• a sensorless and brushless DC motor having a rotor and a plurality of phase coils;
• excitation means for exciting a pair of phase coils from the plurality of phase coils to rotate the rotor;
• detection means for detecting a magnetic pole position of the rotor from a back electromotive force produced in the excited phase coils;
• and
• wherein on activation of the sensorless and brushless DC motor, the control means controls the excitation means to excite one pair of phase coils to rotate the rotor and then to excite another pair of phase coils to position the magnetic pole position in another pair of phase coils, and the control means determines whether or not the rotor vibrates in accordance with the detected magnetic pole position when the rotor starts to rotate and controls the excitation means to stop excitation of a desired pair of phase coils outside another pair of phase coils until the rotor does not vibrate.