Design and Analysis of High Torque Toroidal Motor for Low-Speed Spacecraft Actuators

Spacecraft actuators are the focus of the fast-growing space industry as they are a key functional element in space systems. The desired features of these actuators are - long life, high reliability, high power density, high efficiency, reduced size under deep vacuum and extreme temperature environments, etc. A slow-speed scanning and imaging system intended for spacecraft application traditionally uses either torque motors or concentrated winding PMBLDC motors. As a better alternative, a permanent magnet toroidal winding BLDC motor is proposed in this paper, and its suitability is explored. For the toroidal winding BLDC motor, novel design aspects, such as the concept of phase isolation through flux barriers and stator spacers, are analyzed. Configurations of toroidal winding motors are investigated in this paper to achieve improved torque density and specific power. Considering various variants, the design of the Toroidal Winding - Dual Rotor PM Brushless Motor (TW-DRPMBLM) is carried out using Finite Element (FE) simulation analysis and its performance indices are compared with the slotless Concentrated Winding PMBLDC motor (CW-PMBLDC) for showcasing the superiority and usefulness of the proposed TW-DRPMBDM for the slow-speed scanning and imaging spacecraft application.