| 摘要 |
PURPOSE:To enable continuous operation and to quicken reset operation upon removal of abnormal cause by feeding only exciting current to an AC motor in case of light abnormality. CONSTITUTION:Upon momentary failure of AC power supply, a short circuit switch 20 closes according to the output from a voltage detector 21 to short circuit a speed controller 9 and bring the torque current reference Iq* to zero, thus feeding only exciting current from power inverter 5 to an induction motor 6. Since only the exciting current for the induction motor 6 and the switching loss of the transistor TrI in the power inverter 5 flow from the side of electrolytic capacitor 4 to the side of the power inverter 5, the base of the power inverter 5 is not required to be disconnected upon occurrence of momentary power failure, resulting in continuous operation of power conversion device. |
