| 摘要 |
PURPOSE:To easily detect a change in a current by controlling an inverter part so as to high efficiently operate an induction motor by increasing (decreasing) AC voltage, in the case of increasing (increasing) an inverter input current, when decreasing (increasing) the AC voltage output from the inverter part. CONSTITUTION:A current change detecting device 71 is connected to a shunt resistor 65 provided between one end of an AC power supply 80 and a rectifier 61, to detect a change in an inverter input current flowing from the AC power supply 80 to the rectifier 61. Based on an increase/decrease signal from the current change detecting device 71, a voltage control device 72 decreases AC voltage in the case of increasing of an inverter input current when increasing AC voltage output from an inverter part 63, and on the other hand, increases the AC voltage in the case of increasing of the inverter input current when decreasing the AC voltage output from the inverter part 63, thus controlling the inverter part 63 so as to highly efficiently operate an induction motor 70. |
