Variable reluctance resolver

A variable reluctance resolver comprising:

• a rotor core and stator magnetic poles structured to enable reluctance in a space between the rotor core and stator magnetic poles to be changed by the positions of the rotor core and to make a fundamental wave component of the reluctance variation N cycles per revolution of the rotor core, N being an integer of 1 or more;
• said stator magnetic poles including first magnetic poles having a predetermined number of 3N phases and arranged at equal intervals;
• said stator magnetic poles further including second magnetic poles having a predetermined number of 3N phases and disposed at the central positions between said first magnetic poles;
• excitation coils arranged individually at said first and second magnetic poles and connected in series to each other for each phase of said first magnetic poles and for each phase of said second magnetic poles;
• current detecting means for detecting current values changing due to the variation of the reluctance when an alternating current is applied to the magnetic coils of each phase of said first magnetic poles and said second magnetic poles;
• 3N difference value calculating means for calculating the difference values between the detected current values of said first magnetic poles and second magnetic poles of each phase detected by said current detecting means;
• phase converting means for converting outputs of the difference values from said difference value calculating means into a 2N-phase output;
• and
• signal processing means for calculating rotational angles or rotational speeds on the basis of the converted output of said phase converting means.