| 摘要 |
PURPOSE:To realize highly efficient acceleration at the time of start and reduce the rising time by a method wherein the revolution of a rotor is measured with the position of the rotor and the time for the change of the position and the timing of switching the excited phase of a motor is controlled in accordance with the position and the revolution of the rotor. CONSTITUTION:A CPU 11 outputs a motor control signal 15 for starting a motor 13 to an excited phase switching circuit 12. The excited phase is switched in accordance with the motor control signal 15 to drive the motor 13. When the motor 13 rotates, U-shape, V-shape and W-phase counter electromotive forces which have a phase difference of 120 deg. between each other are generated in motor coils 13a, 13b and 13c respectively and transmitted to a rotor position detecting circuit 14. The counter electromotive forces of the motor coils 13a, 13b and 13c are compared with a common terminal voltage Va and rotor position signals 18 of the U-phase, the V-phase and the W-shape are generated and inputted to the CPU 11. The CPU 11 generates a timing with a phase delay of 30 deg., which is an optimum phase switching timing, from the rotor position signal 18. |
