| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a derivation method of a rotation speed estimate during idling, which is suitable for an AC motor controlling a motor at variable speed while power is supplied to the AC motor from a variable voltage variable frequency inverter. <P>SOLUTION: The AC motor is provided with the inverter 2 supplying desired primary voltage v<SB>1</SB>to an induction motor 1, a current detector 3 detecting primary current i<SB>1</SB>to the induction motor 1 from the inverter 2, a voltage command value operating means 4 generating a voltage command value v<SB>1</SB><SP>*</SP>for generating v<SB>1</SB>, an idling speed estimating means 5 with which the induction motor 1 operates the estimate ω<SB>r</SB><SP>#</SP>of rotation speed during idling, and a sequence circuit 6 commanding operations of them. If the magnitude of current when a part between windings is short-circuited at idling of the induction motor 1 is less than a lower limit value which is previously decided, the idling speed estimating means 5 derives the rotation speed estimate of the motor based on voltage or current supplied to the induction motor 1 from the inverter 2, and the induction motor 1 is re-started by the rotation speed estimate. <P>COPYRIGHT: (C)2009,JPO&INPIT |
