Rotational angle detection device and method for permanent magnet dynamo-electric machine and electric power steering device

A rotational angle detection device for a permanent magnet dynamo-electric machine comprising:

• a stator that includes armature winding;
• a rotor that includes a rotor core and a plurality of permanent magnets;
• a conductive circuit, in which a torque is generated by a current of the armature winding, that includes first conductors extending in an axial direction of the rotor and being disposed in at least two places in a circumferential direction of the rotor, and second conductors for electrically interconnecting the first conductors, wherein,
• the first conductors are each disposed to have a portion protrude from the rotor core outwardly in the diameter direction are each disposed within one of a range of an electrical angle between −45° and +45° in the circumferential direction with a magnetic pole center of each of the plurality of permanent magnets being set as a reference and a range of an electrical angle between −45° and +45° with a position apart from the magnetic pole center by an electrical angle of 90° being set as a reference, and
• the conductive circuit is disposed in at least one place in the circumferential direction;
• and
• a controller that detects a rotational angle of the rotor by measuring a value of the current flowing through the armature winding.