Digital control and optimization of a rolling rotor switched reluctance machine

A motor having a rotor which is free to roll on the inside of the stator, without bearings restraining it to a fixed axis, is proposed. Using the axial rather than the tangential forces between rotor and stator, this motor develops considerable torque at low speeds. A digitally based controller and a power electronic implementation which minimizes vibrational effects and torque pulsations and also increases overall motor efficiency are described. Attention is drawn to the robustness and simplicity of the motor, making it ideal for low-cost applications, where large torque at low speeds is required from a compact gearless construction. Valuable design considerations have been gained by the use of a finite element analysis on the rolling stator switched reluctance motor