| 摘要 |
PROBLEM TO BE SOLVED: To improve current estimation accuracy of an AC motor in a system in which one current sensor is provided for one AC motor.SOLUTION: A current estimation part 17 repeatedly performs following operations at a predetermined period: an inverted dq conversion for calculating current estimation values iu.est, iv.est of other two phases (U phase and V phase) based on values id.lpf, iq.lpf by smoothing previous d-axis and q-axis current estimation values id.lpf, iq.lpf; and a dq conversion for calculating a d-axis and a q-axis current estimation values id.est, iq.est based on a current detection value iw.sns of a sensor phase (W phase) detected by a current sensor and current estimation values iu.est, iv.est of other two phases calculated by the inverted dq conversion. Thereby the current estimation accuracy of the d-axis and q-axis current estimation values id.est, iq.est and current estimation values of other two phases iu.est, iv.est can be improved by coinciding with a phase of the current detection value of the sensor phase iw.sns and phases of current estimation values of other two phases iu.est, iv.est. |
