High-force density linear switched reluctance machine

Unlike its rotary counterpart, the linear switched reluctance machine (LSRM) lends itself to double-sided excitation and multiple translator (or “rotor”) configurations that can yield high-force density designs suitable for controlled linear motion in hostile environments. This paper presents the particular design of a 6:4, double-sided, double-translator LSRM that develops 5.1 lb/in² of air gap force shear. The work develops a permeance tube based method to allow simple algebraic magnetic circuit analysis and associated prediction of flux linkages regardless of the level of magnetic saturation of the ferromagnetic structure. Theoretical static thrust predictions are made based on the calculation of change in stored magnetic coenergy per unit distance of translator movement. Laboratory testing of a proof-of-principle LSRM, built up to verify the theoretical predictions, shows that the calculated and measured average thrust values agree within reasonable error over the range of excitation