Reluctance electric machine having a decreased cross section of rotor

Abstract

A reluctance electric machine which comprises a stator with electric windings, a rotor including ferromagnetic material members, inserted into the stator and separted therefrom by an air gap, and members of non-ferromagnetic material inserted in the rotor in such a way that the cross section of the ferromagnetic material members of the rotor, at least near the air gap, is decreased by the insertion of the members of non-ferromagnetic material in such a way that the ratio between the ferromagnetic material cross section and the whole cross section available does not exceed 0.6, and the ratio between at least one linear dimension of the non-ferromagnetic material members, lying in a plane tangent to the air gap, and the thickness of the machine air gap, does not exceed 5. The electric machine is fed by an electronic circuit for vectorial control (in amplitude and phase) of the current feeding the electric windings of the stator. The rotor may be massive with salient poles, and then the members of non-ferromagnetic material are little cavities hollowed in the surfaces of the rotor which face the air gap. Alternatively, the rotor may have axial laminations, and then the laminations comprise ferromagnetic sheets and alternate non-ferromagnetic intercalary layers, where the thickness of each intercalary layer is at least 2/3 of thickness of each ferromagnetic sheet, and the thickness of each intercalary layer does not exceed 5 times the thickness of the machine air gap.