A novel control method in flux-weakening region for efficient operation of interior permanent magnet synchronous motor

This paper proposes a novel control method for an interior permanent magnet synchronous motor in the flux-weakening region. The proposed method consists of a maximum torque per flux (MTPF) control, and an efficient flux-weakening control under a light load. In order to simplify the MTPF control, a method for approximating the MTPF curve is proposed. In the flux-weakening control, more efficient control is applied by minimizing the armature current under a light load. In the proposed efficient flux-weakening control, the current command generation method, in which the armature current is adopted for the operation along the constant- voltage ellipse, is proposed. The validity of the proposed control method is verified based on simulation and experimental results.