ABSTRACT
The outer-long-primary stator with interior-short-PM-secondary mover leads to the lowest mover weight and to zero stray fields, but, unless the stator primary is supplied in a few sections, the energy consumption tends to be large. Cogging force manifests itself as in flat linear permanent magnet synchronous motors, and the methods to eliminate it, including the drag force, are the same for tubular linear permanent magnet synchronous motors. To increase the airgap flux density, thrust efficiency, axially magnetized permanent magnets may be placed between radially magnetized ones in a kind of Halbach array. Improving the position tracking may be approached many ways, but feed-forward or feedback disturbance observers may be adequate, because in Tubular linear permanent magnet synchronous motors not only temperature and magnetic saturation vary in time, but also the airgap, and, of course, the load.
