Design Principles of a Phase-Shift Modular Slotless Tubular Permanent Magnet Linear Synchronous Motor With Three Sectional Primaries and Analysis of Its Detent Force

This paper investigates a modular slotless tubular permanent magnet linear synchronous motor, which includes several sectional motors by setting flux barriers and rearranging windings. It focuses on the design method of the different combinations with small detent force. The detent force models of the sectional and whole modular motor are established analytically in terms of a Fourier expansion and verified by a prototype. Then the design principles of the sectional motors are analyzed. On the basis of the models, the schemes whose flux barriers' widths equal to one-third of the pole pitch are selected, followed by the comparison of two kinds of different sectional combinations. Their detent-force characteristics are then described in detail. The conclusions about the different combinations are drawn.