FO based independence control of thrust and normal forces in a SLIM

Dynamic mathematic model with thrust and normal forces in a single sided linear induction motor (SLIM) is established according to the flux distribution in the air gap, which is suitable to gap-length changing during operation of a SLIM. According to the operation characteristics of SLIM, its repulsive component and attractive component in the normal force are analyzed, and then a novel decoupling strategy is proposed to control independently the thrust and normal forces using direct flux-linkage orientation (FO), in which a secondary flux-linkage Luenberger observer is adopted. The stable levitation and propulsion of a model vehicle system during levitation is realized by using only SLIM´s. The independence control strategy of forces is verified on a SLIM model vehicle of combined levitation and propulsion.