| 摘要 |
<p>A control system for an induction motor driven by an AC output of variable frequency and voltage produced from an inverter (4) which converts DC power obtained by a converter (2) through conversion of AC power having constant voltage and constant frequency. The system comprises means (8, 9, 10, 11, 13; 23, 24) for estimating the power factor of the induction motor from an input current to the inverter, means (8) for controlling the voltage of the AC output from the inverter when the estimated power factor is outside a predetermined range, and means (7, 8) for restricting the control of the AC output voltage to prevent the ratio between the AC output voltage and the AC output frequency from exceeding a predetermined range.</p> |
