New Equivalent Circuits of Single-sided Linear Induction Motor

Recently, single linear induction motor(SLIM), which comes from rotary induction motor(RIM), has been widely applied in transportation systems, especially in intermediate speed arrange, because of its merits, such as ability to exert thrust on the secondary without mechanical contacts, high acceleration or deceleration, less wear of the wheels, smaller turn circle radius and more flexible road line etc. However, for cut-open magnetic circuit, inherent characteristics of SLIM such as longitudinal end-effect, transverse edge-effect and half filled slots etc are the main subjects by researchers all along. In this paper, T model equivalent circuit, achieved on the base of the one-dimensional magnetic equations of air gap is proposed first. The end effect and edge effect which affect excited reactance and secondary resistance can be rectified by coefficients K’r (s), K’x (s), Cr(s) and Cx(s). The half slots are considered by correcting poles number. From this T model equivalent circuit, two-axis equivalent circuits(dq or αβ) according flux linkage conservation, which unifies with those of RIM, are deduced. The four coefficients of equivalent circuits above are analyzed and the simulation curves are compared with experiments. The results indicate that this T model and new two-axis circuits are very reasonable to describe SLIM performance and control process.