Maximum Efficiency Per Torque Control of IPMSM Based on Loss Criterion Acquisition

This article proposes a maximum efficiency per torque (MEPT) control strategy for interior permanent magnet synchronous motor (IPMSM) based on the acquisition of loss criteria. First, the characteristics and practical occasions of four different efficiency optimization strategies are theoretically analyzed. Based on the mathematical model of IPMSM considering iron loss, the extremum equation satisfying torque control accuracy and loss minimization is established. Meanwhile, a criterion F, which can reflect IPMSM loss is proposed. Criterion F is characterized by crossing the point of zero, which corresponds to the minimization point of loss. Then, the current reference setting method for the MEPT control is designed based on criterion F. In addition, the impact of voltage errors and parameter variations on the accuracy of the current reference setting is evaluated. The proposed method avoids the complex solution process of high-order nonlinear equation in efficiency optimization, thereby simplifying the implementation of the current reference setting. Furthermore, it also avoids the approximate simplification of the current reference solving process, which enhances the precision of the current reference. Finally, the effectiveness and superiority of the proposed method are verified by experiment.