Analysis of a Tubular Linear Permanent Magnet Motor for Reciprocating Compressor Applications

This paper describes a design optimization to achieve optimal performance of a two novel
single-phase short-stroke tubular linear permanent magnet motors (TLPMMs) with rectangular and
trapezoidal permanent magnets (PMs) structures. The motors equipped with a quasi-Halbach
magnetized moving-magnet armature and slotted stator with a single-slot carrying a single coil. The
motors have been developed for reciprocating compressor applications such as household refrigerators. It is observed that the TLPMM efficiency can be optimized with respect to the leading design parameters (dimensional ratios). Furthermore, the influence of mover back iron is investigated and the loss of the motor is computed. Finite element analysis (FEA) is employed for the optimization, and the optimal values of the ratio of the axial length of the radially magnetized magnets to the pole pitch as well as the ratio of the PMs outer radius-to-stator outer radius (split ratio), are identified.