Patent ID: 7872439

Claim:
A motor driving apparatus comprising: a rotor that is rotatable and includes a magnet magnetized to n poles in a multipolar manner in a circumferential direction; a first coil; a first yoke to which a magnetic pole teeth excited by the first coil is formed; a second coil; a second yoke to which a magnetic pole teeth excited by the second coil is formed; a magnetic pole detecting unit including first and second magnetically sensitive poles, wherein the first magnetically sensitive pole senses a magnetic field change occurring as the magnet rotates and outputs a first signal, the second magnetically sensitive pole senses a magnetic field change occurring as the magnet rotates and outputs a second signal, an angle between straight lines connecting each of the center of the first and second magnetically sensitive poles to the rotating center of the rotor has a phase difference of α° compared to the half angle between straight lines connecting each of the center of the adjacent magnetic poles of the magnet to the rotating center of the rotor, a correction unit configured to calculate a first corrected signal by using a first arithmetic equation, and to calculate a second corrected signal by using a second arithmetic equation; and a control unit configured to switch a direction of electricity flowing through the first coil according to the first corrected signal, and to switch a direction of electricity flowing through the second coil according to the second corrected signal, wherein the first arithmetic equation is defined as the first signal×cos(A)+the second signal×sin(A), the second arithmetic equation is defined as the second signal×cos(B)−the first signal×sin(B), and coefficients A and B are determined by α.