| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a controller for induction motors capable of estimating the rotation frequency and phase of a motor without using an output voltage detecting means for an inverter or passing an excessive current when it is restarted. <P>SOLUTION: The controller is constructed of a converter 2, the inverter 4, a current detecting means 5, a voltage detecting means 14 for detecting drop in the input voltage of the converter 2, a speed detecting means 7, and a control unit 10. The control unit 10 controls the inverter 4 by vector control in which the voltage and current of an induction motor 6 are converted into q-axis and d-axis orthogonal thereto and they are independently controlled. A d-axis voltage reference is converted in terms of a frequency, which is added to an inverter output frequency to correct it, and control is thereby carried out so that the d-axis voltage reference is zeroed. When the voltage detected by the voltage detecting means 5 becomes equal to or lower than a predetermined value, both a d-axis current reference and a q-axis current reference are changed to zero. <P>COPYRIGHT: (C)2007,JPO&INPIT |
