Force performance of single-sided linear induction motors with dual-branch phase winding in low-speed Maglev train

The low-speed Maglev train adopts single-sided linear induction motors (SLIMs) as traction part. Although the phase winding normally adopts single-branch in order to avoid circulating current caused by longitudinal end effect, the influence of circulating current is not investigated in detail. This paper calculates the circulating current and force performance of SLIMs with dual-branch by 3D finite element method (FEM). Firstly, two kind connections of dual-branch phase winding are introduced, called continuous connection or interval connection respectively. Secondly, the circulating current and force performance are obtained at both starting and steady state, and then the effect of circulating current on force performance is deduced. Thirdly, the contribution to force performance by each coil assembly is studied. Finally, the circulating current, force performance and efficiency under different air gap length are analyzed. It is demonstrated that the dual-branch connection has better force performance than single-branch one, but also bigger current unbalance and lower efficiency.