Patent ID: 7800337

Claim:
A control apparatus for an AC rotary machine, wherein the AC rotary machine is driven on a basis of current commands on rotating two-axis coordinates which rotate at an angular frequency of the AC rotary machine, the control apparatus comprising: current detection means for detecting currents of the AC rotary machine; coordinate transformation means for transforming current detection values from said current detection means, into current detection values on the rotating two-axis coordinates; first voltage command calculation means for calculating first voltage commands on the rotating two-axis coordinates, from relational formulas among the current commands on the rotating two-axis coordinates, the angular frequency and a plurality of electrical constants of the AC rotary machine; second voltage command calculation means for calculating second voltage commands on the rotating two-axis coordinates, on a basis of difference currents between the current commands on the rotating two-axis coordinates and the current detection values on the rotating two-axis coordinates, so that the difference currents may converge into zero; third voltage command calculation means for calculating third voltage commands on the rotating two-axis coordinates, by adding the first voltage commands on the rotating two-axis coordinates and the second voltage commands on the rotating two-axis coordinates; voltage application means for applying voltages to the AC rotary machine on a basis of the third voltage commands on the rotating two-axis coordinates, wherein said first voltage command calculation means sets at least one of the plurality of electrical constants with a constant set value inputted from outside; and constant measurement means for calculating the constant set value on a basis of the second voltage commands from said second voltage command calculation means.