Patent ID: 7026774

Claim:
A rotor position determination device of a rotating electric machine for determining a position of a rotor of the rotating electric machine relative to m-phase (m is an integer equal to or more than 2) armature coils, said rotating electric machine including a stator having the m-phase armature coils, and the rotor having a magnetic field, comprising: transient current energizing means for performing, for each of said m-phase armature coils, a transient current energizing process for temporarily applying a DC voltage to the armature coil of each phase of said stator to pass a transient current through the armature coil of each phase; and rotor position determination means for detecting the transient current passed through each of said m-phase armature coils in said transient current energizing process and determining the position of said rotor relative to said m-phase armature coils from the detected transient currents.