An improved series equivalent circuit of a single-sided linear induction motor

The derivation of the equivalent circuit for a single-sided linear induction motor (SLIM) is not straightforward. Especially if it includes longitudinal end effects from the cut-open primary magnetic path, transverse edge effects from the differing widths between the primary lamination and secondary sheet, and half filled primary slots. This paper proposes an improved series equivalent circuit for this machine. The longitudinal end effects are estimated using three different impedances representing the normal, forwards and backwards flux density waves in the air-gap. The transverse edge effects accounted for with a correction coefficient K_t and an air-gap flux density correction coefficient K_b. Using the series circuit, the performance of the SLIM was assessed in a similar manner to a rotating induction machine. A 4 kW SLIM prototype was tested which validated the simulation technique.