No abstract

This paper proposes a novel deadbeat torque and flux control (DB-DTFC) to reduce torque ripple for switched reluctance motor (SRM). DB-DTFC combines the advantages of direct torque control (DTC) and space-vector modulation (SVM). DB-DTFC leads current vector control into DTC in order to find the equation between torque and current through deadbeat prediction theory i.e. a beat reaches a given point. In addition, the deadbeat calculation module here is similar to that of permanent magnet synchronous motor. Based on dq0 reference frame of SRM, the most suitable dq0 axis current of next moment corresponding to different torque errors is calculated and predicted. According to the calculated dq0 axis current, the optimal space voltage vectors can be selected to reduce torque ripple. In order to verify the effectiveness and correctness of the proposed scheme, DB-DTFC is verified and compared with the DTC-SVM by simulation.

In this study, the non‐linear deadbeat direct torque and flux control (N‐DB‐DTFC) scheme is proposed for switched reluctance motor (SRM) to achieve torque and flux precise control. For torque control part, the Fourier series form of inductance is used to establish the non‐linear torque model of SRM. As for the flux control, stator flux‐oriented is adopted to achieve the flux control and simplified calculation in N‐DB‐DTFC. In addition, the synthetic voltage vectors are applied by pulse‐width modulation. In order to assess the performance of N‐DB‐DTFC, the comparison of torque ripple is analysed among the traditional deadbeat controls in the simulation and experiment. Although, for the torque transient response, three deadbeat controls show the strong robustness and adaptability. In the results, the proposed N‐DB‐DTFC strategy shows better reflection in terms of lower torque ripple. Moreover, the results of simulation and experiment are based on a three‐phase 12/8‐poles SRM.

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.