Analysis of forces in combined levitation-and-propulsion SLIM system

Normal force in single-sided linear induction motor (SLIM) is normally restrained in SLIM transportation system. We developed a combined levitation-and-propulsion device to utilize the normal force for levitation and thrust for propulsion with only a SLIM in our Lab. This paper describes a mathematic model for the analysis of normal -and- thrust forces through a space high harmonic method. A scheme to control the normal force by adjusting the rotor flux, stator flux or magnetizing flux of the motor in low slip domain is presented, which makes it possible to control the normal force and thrust independently. Simulation and experiments verify the validity of the proposed method.