Modelling Framework and Insights About a Novel Low-Velocity Segmented Linear Motor Design

A novel concept for a segmented linear interior-mounted permanent magnet motor is introduced. The favourable scaling properties of permanent magnet motors are exploited by making the stator and mover out of short tubular sections. These are cooled with liquid metal cooling tubes and joined into motor fibres, thus improving force density and manufacturability. Motor efficiency is improved by independently controlling the coil repeat units and setting the coil electric current proportional to the local magnetic field. A low-computational-cost modelling framework based on a differential element approximation is adapted to this motor configuration and used to generate optimal motor geometries for a case study involving the upgrade of a shoulder-assistance motor. Design guidelines and trade-offs associated with this novel motor configuration are discussed and compared to existing tubular linear motors.