| 摘要 |
PROBLEM TO BE SOLVED: To obtain a detection method in which the influence of a current pulsation due to a PWM voltage with reference to a plurality of AC motors is reduced and in which a current to the plurality of AC motors can be controlled with high accuracy by a method wherein inverter output currents at two phases are sampled separately for the respective AC motors at the maximum amplitude value of carrier waves or at a timing close to it. SOLUTION: Two AC motors 1A, 1B are driven by outputs of two PWM inverters in which individual modulating-wave signals and a common carrier-wave signal have been superposed. In this case, the A-phase inverter output current and the B-phase inverter output current of output signals from the PWM inverter 3A and the PWM inverter 3B with reference to the AC motors 1A, 1B are sampled sequentially, they are A/D converted, and they are fed back to a voltage command part so as to be output as modulating-wave signals. They are sampled separately for the respective AC motors at the timing of the maximum amplitude value of carrier waves, and a sampling operation to the individual AC motors 1A, 1B is performed at the maximum amplitude value of the carrier waves. Thereby, the influence of a current pulsation due to a PWM voltage is reduced, and a current can be controlled with high accuracy. |
