| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a device and a method for enabling detection, etc. of the idling or the slippage of the drive shaft of an induction motor, without using a speed sensor, or even if the relative speed of each induction motor is small. <P>SOLUTION: An acceleration estimating apparatus 50 is equipped with a phase computing unit 51, which calculates and outputs a phase θ on a static coordinate from batch current values Iu and Iv outputted from a current sensor 30; a BPF 52 which makes the phase θ pass through a given band and outputs it as a phase θ'; a differential computing unit 53, which computes the estimate f1 of inverter frequency by getting the first-order derivative of the phase θ'; an LPF 54 which passes a given zone of the frequency f1 and outputs it as a frequency f1', and a differential computing unit 55 which computes a degree of acceleration estimate αi, by obtaining the first-order derivative of the frequency f1'. <P>COPYRIGHT: (C)2004,JPO |
