| 摘要 |
PROBLEM TO BE SOLVED: To reduce the cost of a three-phase brushless motor and enhance the reliability thereof. SOLUTION: The angular position of the rotor 1 of a three-phase brushless motor is detected when a position detection signal obtained based on a Hall element 4 crosses a specified reference level in proximity to its a.c. zero level. Reference clock pulses are counted using a counting means, starting with a reference clock pulse generated immediately after this crossing, and a three- phase excitation switching control signal is produced. The rotation of the rotor 1 is controlled so that the difference between the time of the position detecting signal's zero crossing and the time at which the reference clock pulse is generated close to the zero crossing time will be zero. |
