| 摘要 |
PROBLEM TO BE SOLVED: To prevent breakdown by an excessive current of a semiconductor switching element to drive a brushless motor without use of a complicated current control system. SOLUTION: An induced voltage detecting section 5 obtains a position detecting signal of a rotor and a power feeding coil switching section 6 sequentially switches a stator coil. Moreover, a velocity variation control section 7 detects velocity variation during rotation of motor 1 from the position detecting signal and also obtains amount of change of voltage applied to the motor 1 during rotation to control velocity variation depending on a current detected by a motor operation current detecting section 8. Next, an average velocity control section 10 compares a moor average velocity calculated from the position detecting signal with a command from a velocity command section 9 to obtain an average application voltage of motor 1 during rotation. In addition, an application voltage varying section 11 varies the average application voltage of motor and also varies momentary application voltage of motor obtained in the velocity variation control section 7 to determine the application voltage of motor. A drive signal generating section 12 generates a drive signal of a semiconductor switching element group 3 to driven the motor 4 based on the application voltage obtained as explained above. |
