Apparatus for estimating rotational position of predetermined magnetic pole of rotary electric machine

An apparatus for controlling a rotary electric machine including a rotor with a field winding for generating at least one pair of magnetic poles, and a stator with an armature winding, the field winding and the armature winding being magnetically coupled to each other when energized, the apparatus comprising:

• a voltage applier that applies a high-frequency voltage to one of the field winding and the armature winding, one of the field winding and the armature winding being defined as an input winding, and the other thereof being defined as an output winding;
• a current detector that detects a high-frequency current flowing through the output winding based on the applied high-frequency voltage, the high-frequency current including therein information associated with the rotational position of a target magnetic pole of the rotor as a predetermined one of the magnetic poles;
• and
• an estimator that estimates the rotational position of the target magnetic pole of the rotor according to the high-frequency current detected by the current detector.