| 摘要 |
PURPOSE:To enable to stably operate a motor even at a low frequency operating time by correcting the voltage set value by the variation of the output voltage of an inverter, thereby enabling to set the output voltage to the set value even when the phase of a load current is varied. CONSTITUTION:The output voltage Vi of an inverter 5 is detected by a voltage detector 15, a voltage controller 15 receives an output of the detector 15 and an output of a voltage pattern generator 9, compares the both outputs, corrects the voltage set value Vd by the output voltage variation of the inverter thereto, and inputs it to a multiplier 12. When a lower power factor is deteriorated so that the output voltage Vi of the inverter 5 becomes higher than the set voltage value vd, the voltage set value side input of the multiplier 12 decreases corresponding to the variation of the output voltage Vi. Accordingly, the peak of a sinusoidal wave signal Vdf decreases, and the output voltage Vi is controlled toward the voltage set value Vd. |
