| 摘要 |
PROBLEM TO BE SOLVED: To prevent influence by kickback voltage and external disturbance noise produced in a drive coil in a sensorless motor. SOLUTION: A kickback voltage is generated at the point when output transistors 7 to 12 change to OFF from ON, namely when the drive coils 1, 2, 3 change to non-conductive condition from the conductive condition, and the clock pulse for DFF 20, 21, 22 to fetch the outputs of comparators 4, 5, 6 to DFF 20, 21, 22 is generated during the period between the time delayed by the predetermined period from the kickback voltage generating time and the zero-cross point of the drive voltage generated in the drive coils 1, 2, 3. As a result, outputs of DFF 20, 21, 22 not including the influence of kickback voltage and external disturbance noise can be applied to the logic circuit 23 to surely drive and brake the motor. |
