Design of a Wind Turbines Synchronous Generator, with Longitudinal Excitation from Permanent Magnets

Abstract

The design of a brushless generator, with excitation from permanent magnets, is proposed in this paper. A distinctive feature is the passage of magnetic flux in the direction longitudinal to the axis of rotation of the rotor, which made it possible to change the design of the generator. A permanent magnet is used for the excitation. It is placed in the center of the rotor of the generator, and magnetized in the longitudinal direction. At the ends of the rotor, the poles made of the ferromagnetic material are installed, which serve to distribute the magnetic flux excitation along the teeth of the stator, and the stator itself can be made of plastic or other non-magnetic materials, such as ceramics. This is due to the change in the direction of the passage of the magnetic flux excitation from transverse to longitudinal, so the main frame of the stator can be made of non-magnetic material. The magnetic core is an array of rectangular pins located around the circumference, inside the stator, in the longitudinal direction. The coils of the output winding are installed in the middle of the pins, and cutouts in the area of the pins installation are provided in the non-magnetic stator. Thus, during the assembly of the generator stator, the pins of the charged ferromagnetic material are installed in the assembly with the output winding coils, and the corresponding cutouts from the inside of the stator are used for fastening. Cutouts improve heat dissipation from coils as they come in contact with the external environment. The listed design features of the generator provide a cost reduction, which is especially important for the small and medium power range applications. It is established that the proposed generator design is characterized by a double frequency of the output voltage.