Abstract

An inverter control apparatus for controlling a command frequency and a command voltage which are supplied to an inverter which then supplies AC power of a desired frequency, accordingly, to an induction motor. The inverter control apparatus receives a requested rotational speed of the motor and an actual rotational speed of the motor is obtained by detecting a frequency of a fluctuation component of a drive current supplied from the inverter to the induction motor. The difference between the requested rotational speed and the actual rotational speed represents a slip amount, which is added to the requested rotational speed to produce a command frequency. The command voltage is set to a voltage acquired when the monitored drive current is at a minimum value. Thus, the inverter control apparatus is able to maintain power consumption at the lowest possible level in response to changes in the operating environment without requiring a motor constant input or a motor speed detector, while compensating the slip ratio of the induction motor to maintain the motor speed at a target level.

Other References

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