Patent ID: 7423401

Claim:
An apparatus for measuring constants of an AC rotary machine, comprising: said AC rotary machine; a power conversion device for converting an inputted voltage command signal into a single-phase AC power, and feeding the single-phase AC power to said AC rotary machine; a current detection device for detecting a current of the single-phase AC power fed from said power conversion device to said AC rotary machine; a first control device for generating a voltage command signal corresponding to an AC voltage to be applied to said AC rotary machine from said power conversion device, and outputting the generated voltage command signal to said power conversion device; and a second control device for calculating the constants of said AC rotary machine based on a relationship between the voltage and the current of the single-phase AC power fed to said AC rotary machine, wherein said first control device generates the voltage command signal and controls said power conversion device so as to feed the single-phase AC power having at least one frequency selected in a range, which is equal to or higher than a lower limit frequency of 0.006 Hz, and which is equal to or lower than an upper limit frequency of 1.5 Hz, to said AC rotary machine at least once, so that said second control device calculates the electric constants of said AC rotary machine based on the voltage command signal.