Axial flux permanent magnet machine with field-weakening capability
Research on modular permanent magnet motors has led to a new concept for a small, flat motor that is an attractive candidate for application in computer disc drives. The motor has an axial-flux configuration that evolved from a radial-flux design distinguished by its use of sinusoidal-shaped stator pole faces. When this pole shaping is converted into an axial-flux design, the stator poles take on a "flower petal" shape. Since the poles are linked with a sinusoidal flux emanating from the rotor permanent magnets, the torque produced by the machine can be nearly constant. The topology is compatible with high-volume manufacturing and has fewer parts than the disc drive motor commonly used today. A patent is being filed on this concept.