| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for deriving an estimated value of rotation speed during idle, suitable for alternating-current motors, wherein power is supplied from a variable voltage, variable frequency inverter to an alternating-current motor and further the motor is subjected to variable speed control. <P>SOLUTION: The circuitry for attaining the above object is constructed of: an inverter 2 that supplies an induction motor 1 with a desired primary voltage (v<SB>1</SB>); a current detector 3 that detects the primary current (i<SB>1</SB>) from the inverter 2 to the induction motor 1; voltage command value computing means 4 for generating a voltage command value (v<SB>1</SB><SP>*</SP>) for generating the desired primary voltage (v<SB>1</SB>); idling speed estimating means 5 for computing an estimated value (ω<SB>1r</SB><SP>#</SP>) of rotation speed when the induction motor 1 is idling; and a sequence circuit 6 that instructs these operations. In the idling speed estimating means 5, the method for deriving the above estimated value is changed based on a current value when windings are short-circuited to each other while the inductor motor 1 is idling. <P>COPYRIGHT: (C)2007,JPO&INPIT |
