| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a control device for an AC motor capable of accurately controlling an AC voltage effective value applied to the AC motor in which load fluctuations are large and a power factor rapidly changes. <P>SOLUTION: This control device controls an AC voltage applied to the AC motor 4 by driving thyristors located between an AC power supply 3 and the AC motor 4. This device comprises a voltage detector 6 for detecting an actual voltage value applied to the AC motor 4 and outputting a detected voltage value, a voltage controller 18 for comparing a voltage command value with the detected voltage value to decrease a value of a firing angle when the voltage command value is larger than the detected voltage value and increase a value of the firing angle when the voltage command value is smaller than the detected voltage value for outputting a value of the firing angle, and a thyristor firing signal generating circuit 10 for firing the thyristors 1, 2 at timing corresponding to the value of the firing angle in which the value of a voltage phase of the AC power 3 is outputted from the voltage controller 18. <P>COPYRIGHT: (C)2003,JPO |
