| 摘要 |
PURPOSE:To effectively reduce torque ripples, produced in an induction motor to be controlled, due to the offset of a current detecting means. CONSTITUTION:An average speed calculator 11 averages signals representing the angular velocity omegar of an induction motor 1, and thereby calculates in sequence the average values omegaav of speed with the equivalent of speed ripples subtracted. A peak value detector 12 detects in sequence the peak values omegapk of speed ripples at the angular velocity omegar. A current offset calculator 13 calculates the difference between the speed ripple peak value omegapk and the average speed value omegaav as the amplitude of speed ripples. Further, the current offset calculator 13 calculates a phase U offset correction command value Iuoff and a phase W offset correction command value Iwoff through arithmetic operation based on the amplitude. These values are fed to computing units 14a, 14b, and the offset of three-phase current converter 9, a current detecting means, is thereby corrected. |
