| 摘要 |
PURPOSE:To prevent malfunction of circuit in an inverter control section and to protect breakdown of semi-conductor in the inverter, by controlling output voltage and output frequency of inverter to be constant against fluctuation of source voltage. CONSTITUTION:If the voltage of an AC power source 1 drops when an inverter 5 is operating under steady load, voltage V1 to be fed to an inverter section 4 also drops to increase current f3 owing through an induction motor 6 abruptly. The voltage V1 is fed to a DC/DC converter circuit 8 in order to prevent abrupt current increase then fed through a V/F converter circuit 9 to a microcomputor 10. The microcomputor 10 modifies patterns of voltage and frequency to be outputted from the inverter section 4 to the induction motor 6 such that a high voltage is provided for same frequency. |
