Minimization for current peak-to-peak value in switched reluctance motor

Abstract

For switched reluctance motor (SRM), due to the excessive peak-to-peak current occurs at the initial stage under the direct instantaneous torque control (DITC) algorithm, the motor efficiency has been affected to some extent. For this propose, a DITC optimization algorithm combined with high torque per ampere (HTPA) is introduced in this paper. Based on the traditional maximum torque-to-current ratio (MTPA) principle, the changing points of the inductance slope can be calculated. These points are also refer to the maximum torque-to-current ratio. Taking these points as the basis for sector division of the mechanical angle of each phase, the operation rule is optimized in the newly divided interval to select the corresponding voltage vector. The optimal voltage vector is obtained by the method of segmented variable duty cycle modulation. The new algorithm was validated on a three-phase 12/8 switched reluctance motor. Compared to conventional DITC, HTPA-DITC reduces peak current evidently. At the same time, the three- phase stator current is reduced under the same load conditions, thereby increasing the torque-to-current ratio of the motor.