Phase Commutation Optimized Control for Linear-Rotary Switched Reluctance Motor

The traditional DTC method directly controls the torque and flux linkage without model calculation, which is beneficial to restraining torque ripples. However, the LRSRM not only provides the torque required for rotary motion, but also provides the axial force required for linear motion. Hence, the winding usually works in two-phase excitation mode. Given the different torque output capabilities of the front and rear phases under different rotor position angles, the conduction angles of the adjacent two phases can be further optimized. In this paper, a phase commutation optimized method is proposed to improve the torque generation between two neighboring phases and reduce torque ripple. Firstly, the hysteresis-loop control of the flux linkage is removed, which can reduce the calculation burden of digital controller. Secondly, the sector division and voltage vector selection without flux hysteresis control are redesigned. Experimental results verify the effectiveness of the proposed method. The phase current in negative torque region is reduced, and the torque ripple is suppressed as well.