A Slotless PM Variable Reluctance Resolver With Axial Magnetic Field

Abstract

The stator-PM machine concept has been practiced on the recently proposed stator-PM variable reluctance (VR) resolver. When inheriting the simple and sturdy rotor structure of the conventional VR resolver, the novel stator-PM VR resolver provides a chance to avoid the high-frequency excitation by the unique PM back electromotive force decoding solution. This article extends this stator-PM VR resolver category with the axial magnetic field technology. The axial slotless structure makes the VR resolver compact and much smaller than the radial field prototypes. The thin and light leaf-style rotor is suitable for the super-high-speed applications, as the additional inertia due to a sensor is not welcome in those scenarios. Additionally, the printed circuit board replaces the winding coils in the regular VR resolvers, significantly simplifying the manufacturing. The design with even and odd poles cannot share the same principle, so they are discussed separately. The prototypes with 4-X and 5-X configurations are tested in the experiment setup respectively to validate the analysis of the proposed structure. Moreover, the 4-X resolver is integrated with a permanent magnet synchronous machine, and a motor driver with the space vector modulation on the basis of the specific resolver decoder is built.