Cycloidal Reluctance Electric Machine

A variable reluctance electric machine with a two-order rotor motion characterized by rotation around the center of the rotor and orbiting around the center of the stator is studied. One motivation for adopting such rotor motion would be to allow torque generation through both the radial and tangential components of the electromagnetic forces created in the airgap, as opposed to common rotary machines in which torque is a byproduct of the tangential component of the airgap electromagnetic forces only. Furthermore, the rotor motion provides a built-in gearing action similar to a cycloidal drive which allows natural torque multiplication. Due to the reluctance nature of the torque, and because of the distinctive rotor motion profile which resembles the motion of a cycloid, the studied machine is called a cycloidal reluctance (CR) electric machine (CRM). In this paper, the principle of operation of CRM is explained, and its performance is compared to a counterpart switched reluctance machine (SRM). A prototype is built, and the theoretical torque calculations are validated by experimental measurements.