| 摘要 |
PURPOSE:To reduce the pulsation of a torque by controlling so that the distortion rate of the output voltage of an inverter becomes minimum in a rotating speed range corresponding to the resonance point. CONSTITUTION:When a speed range is N<Nf or NB<N, the DC voltage Ed of the input side of an inverter 4 is controlled to the prescribed value set by a voltage setter RH2, the AC voltage VOUT of the output side of the inverter 4 accords with the set value of a setter 8, and automatically controlled to be proportional to the speed N. When the speed N passes the range of Nf<=N<=NB, the contact of the switch 15 is switched to the reverse opened and closed states to the shown state. Thus, a signal compared with a carrier triangular wave TW is switched to the prescribed reference set by a setter RH1 by a pulse width modulator 11 at the inverter 4 side. When this reference is set to minimize the distortion rate of the output voltage waveform of an AC power source VVVF, the pulsating torque of the motor 6 can be reduced. |
