Synchronous Electric Generator With Double Excitation

Abstract

This paper aims to show how an electric generator was developed in an original version with double excitation. The main objective was to achieve a higher power generator, correlated with a smaller mass, for a given volume, destined for the specific applications in the UAV (unmanned aerial vehicle) domain. The stator of the experimental model of the developed electric machine is made of a lamination stack of sheets in the form of cylinder on which toroidal coils are made. This electric machine differs from a classic one by the fact that the stator has both sides of the coils (which cover both the outer surface of the stator cylinder and its inner surface) active both at the exterior and the interior air gap, in the heteropolar magnetic field, generated by the external inductor and the inner inductor, respectively. The two inductors are made with permanent magnets and are fixed to the double rotor. The electromotive forces induced in the coils due to their interaction with the permanent magnets from the inside and the outside are gathering, thus increasing the specific power of the electric machine. To reduce the mass, where no parts made of ferromagnetic materials were needed, a synthetic insulating modern material was used, known under the trade name as ketron 1000 PEEK. This material has superior mechanical strength and relatively small weight relative to metals.