| 摘要 |
PURPOSE:To reduce the harmonic current components of currents to be supplied to an AC motor by operating the harmonic current components on the output side of a main power converter from the phase reference and amplitude refer ence of the output currents of the main power converter, and negating the harmonic current components. CONSTITUTION:The harmonic currents of a main inverter are sought in advance by subtracting main inverter basic currents from main inverter output currents. Next, a harmonic current arithmetic unit 21 is set so that it may output harmon ic current components according to them when an amplitude reference Im* and a current phase reference theta* are input. Here, a PWM control circuit 17 compares the currents outputted by a sub inverter 15 and detected with a current detector 6c with the harmonic currents outputted by the harmonic current arithmetic unit 21, and controls the gate signal of the sub inverter 15 so that it may negate the harmonic currents. Hereby, harmonic currents practically cease to flow to an induction motor 5. |
