New Structures of Brush and Brushless DC Motors using Soft Magnetic Composites for Automotive Applications 2001-01-0400

The original brush and brushless DC motor structures presented in this paper make use of a special winding technique which presents several advantages: the copper volume of the motor is minimized, the mechanical structure is well adapted to the pressing process because the armature is designed with a small number of relatively wide slots and the winding process is easier. The isotropic properties of soft magnetic composites are also used to design a magnetic circuit where the magnetic flux is circulating in three dimensions. It is then possible to maximize the torque-to-weight ratio and to minimize the total axial length of the motor. This paper describes an efficient use of a new technology of magnetic material that needs a new structural design approach taking into account the advantages and constraints of the material, and that the direct replacement approach is usually not optimal.