Patent ID: 7592785

Claim:
A control apparatus for controlling an exciting current supplied to an exciting winding of a field winding type dynamo-electric machine to obtain a demanded output thereof, comprising: an exciting current detecting circuit configured to detect the exciting current of the dynamo-electric machine, and to output a detected exciting current; a rotation speed detecting circuit configured to detect a rotation speed of a rotor of dynamo-electric machine and to output a detected rotation speed of the rotor; an output estimating circuit configured to estimate an output of the field winding type dynamo-electric machine based on a predetermined relation among the detected exciting current, the detected rotation speed, and the output of the field winding type dynamo-electric machine, and to output an estimated output resulting from the estimation; and an exciting current control circuit configured to correct the exciting current of the dynamo-electric machine based on the estimated output of the dynamo-electric machine so as to obtain the demanded output, and to supply the corrected exciting current to the exciting winding of the dynamo-electric machine; wherein the output estimating circuit includes means for performing an estimation of the output of the dynamo-electric machine in consideration of a multi-valued functionality of the output of the dynamo-electric machine with respect to the exciting current of the exciting winding.