| 摘要 |
PROBLEM TO BE SOLVED: To maintain an output torque at a target value, without being affected by the frequency characteristics of a control system and at the same time, drive an AC electric motor without reducing efficiency, when performing the current control of the AC electric motor. SOLUTION: A phase current detection instantaneous value iU supplied to a three-phase AC electric motor 4 is subtracted from an AC current command value iUR for calculating an error iUE, amplitude compensation and phase advance compensation are made with an amplitude compensation value and a phase compensation value being calculated, based on a rotary speed VN being detected by a rotary speed sensor 15 for detecting the rotary speed VN of a three-phase AC electric motor using a compensation part 19 for the amplified phase current command value iUC, and a three-phase inverter 13 is driven based on the compensated phase current command value, thus rotating and driving the three-phase AC electric motor 4 and preventing phase delays and amplitude decrease for the AC current command value iUR of the phase current detection instantaneous value iU. |
