A New Field-Weakening Control Scheme for Surface Mounted Permanent-Magnet Synchronous Motor Drives

This paper presents a new field-weakening control scheme for surface-mounted permanent-magnet synchronous motor (SMPMSM) drives. The proposed method can determine either the constant torque limit control mode or the field-weakening control mode which should be applied to the drive under different operation conditions and variations of system parameters. In addition, the minimum copper loss operation can be preserved to achieve high efficiency and the smooth transition between these two control modes can be obtained by the proposed control. Hence, the proposed scheme is quite suitable for the application of wide speed range operation and/or battery powered SMPMSM drives such as electric vehicles. A digital signal processor (DSP) controlled prototype is built and some experimental results are provided to show the promising features of the drive by using the proposed scheme.