A loss-minimization scheme for direct thrust-controlled linear induction motor drives

Due to the existence of end-effects and large mechanic clearance, the parameters of linear induction motor (LIM) are variable and the efficiency is lower than that of rotary induction motor (RIM). This paper proposes a strategy to minimize the losses for direct thrust-controlled linear induction motor drives. The proposed strategy, which is based on a novel search algorithm, chooses primary current as controlled variable and uses variable flux step to speed up the convergence process. The search algorithm is fast and insensitive to the parameter variations. Experimental results demonstrate the effectiveness of the proposed scheme.