| 摘要 |
PROBLEM TO BE SOLVED: To provide a rotation state detection device which appropriately detects a rotation state of a motor. SOLUTION: The rotation state detection device includes a cutoff frequency operating means 14 to calculate a cutoff frequency from an output ripple current output according to the rotation state of the DC motor, a cutoff frequency setting means 15 to set the calculated cutoff frequency to a set cutoff frequency, a filter means 1 to remove a high-frequency noise component according to the set cutoff frequency, and a rotation state detecting means 3 which detects the rotation state of the DC motor referring to a waveform of the ripple current after the high-frequency noise component is removed, in which the rotation state detection device further includes a rotation state determination means 16 which determines whether the DC motor rotates in a steady manner or not, and a cutoff frequency update means 17, wherein if the motor rotates in the steady manner, the update means permits the cutoff frequency setting means 15 to set the calculated cutoff frequency to the set cutoff frequency, while if the motor does not rotate in the steady manner, the update means does not permit the cutoff frequency setting means 15 to set the calculated cutoff frequency to the set cutoff frequency. COPYRIGHT: (C)2007,JPO&INPIT
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