| 摘要 |
PROBLEM TO BE SOLVED: To provide a control device for an AC motor which reduces phase delay of a filter for cancelling a harmonic pulsation component and a switching noise.SOLUTION: In a control device for an AC motor, a moving average filter calculates a moving average for a predetermined integration term T for at least one of a d-axis current Id and a q-axis current which are obtained by performing dq transformation on a phase current detection value. On a frequency characteristic chart in which a lateral axis is adjusted in such a manner that gains in a low frequency domain are equalized between the moving average filter and a primary delay filter, in a high frequency domain in which an angular frequency ω is equal to about 2 to 10×f, the gain of the moving average filter is smaller than that of the primary delay filter. In particular, if the angular frequency ω is equal to 5 or 10×f, the gain becomes 0. In a nearby frequency, the gain is also sufficiently small, such that an amplitude can be significantly reduced in comparison with the primary delay filter. Namely, by appropriately setting the integration term T, a filter having a stronger amplitude reduction capability than the primary delay filter can be provided and disturbance can be significantly cancelled.SELECTED DRAWING: Figure 4 |
