| 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 an inverted dq conversion for calculating a current estimation value iw.est of a sensor phase (W phase) based on previous d-axis and q-axis current estimation values id.lpf, iq.lpf; a dq conversion for calculating a d-axis and a q-axis current correction values id.crr, iq.crr based on current estimation error &Dgr;iw of the sensor phase obtained from the current estimation value iw.est of the sensor phase and a current detection value iw.sns of the sensor phase detected by a current sensor; and a correction process for obtaining latest d-axis and q-axis current estimation values id.lpf, iq.lpf by correcting previous d-axis and q-axis current estimation value id.lpf, iq.lpf by using d-axis and q-axis current correction values id.crr, iq.crr. Thereby the current estimation accuracy can be improved, and an operation load can be reduced by decreasing the number of times of multiplications in the inverted dq conversion and the dq conversion. |
