Maximum Thrust per Ampere of Linear Induction Machine Based on Finite-Set Model Predictive Direct Thrust Control

One of the methods that is used to increase the efficiency of the linear induction machine (LIM) is the maximum thrust per ampere (MTPA), where the same thrust can be achieved with a lower value of the primary current. Consequently, the power loss can be decreased and the efficiency be increased. However, so far, no quantitative focus exists to increase the efficiency of the LIM. This article proposes the MTPA-based finite-set model predictive control. The concept of field-oriented control is used to achieve the condition of MTPA. Based on this condition, the proposed control method can be developed by adjusting the value of the primary flux linkage. The proposed control method depends on both thrust and primary flux linkage and this proposed method is called finite-set model predictive direct thrust control (FS-MPDTC). Comparison between the FS-MPDTCs with and without MTPA is presented to illustrate the effectiveness of the proposed method. A prototype test platform is developed in the laboratory with two 3 kW arc induction machines to verify the proposed method. Analysis for both comprehensive simulation and experimental results are conducted in this article.