| 摘要 |
PROBLEM TO BE SOLVED: To obtain automatically q-axis inductance Lq of a synchronous motor with high precision by using a control unit of a synchronous motor. SOLUTION: A rotor is set in the state of stop. A q-axis current command is set as a first q-axis current command value. A d-axis current command is set as a first d-axis current command value. A d-axis current step command having a prescribed height is applied to the control unit. A voltage value is obtained by subtracting a voltage of the amount of voltage drop due to primary resistance of the motor from a d-axis voltage command value produced corresponding to deviation of the d-axis current detection value to the step command. The voltage value is integrated over a first integration time which is previously determined, and an integration value vd- sum is produced. Variation Δid of the d-axis current detection value at the end time of integration to the d-axis current detection value at the start time of integration is produced. Similar calculation is executed to the q-axis, and integration values vq- sum and Δiq are produced. K=(vq-sum/vd-sum).(Δid/Δiq) is calculated. Known d-axis inductance Ld is used, and q-axis inductance is calculated by using a formula Lq=KLd. |
