Validation of a modified direct-self control strategy for PMSM in railway-traction applications

This paper proposes and validates a modified direct-self-control (M-DSC) as a new control strategy option for permanent-magnet synchronous machine (PMSM) in railway traction applications. Taking into account all the specific requirements of the application and in order to stand-out its traction application capacity, a detailed analysis of the torque optimization technique (MTPA) and machine start-up capacity with low switching frequency have also been presented. Moreover, in order to achieve a robust control, two online permanent-magnet flux estimation techniques have been implemented. Experimental results, obtained from a 100-kW test bench, have demonstrated that the M-DSC control strategy fulfills all the railway-traction requirements: especially its very good dynamic performance. Therefore, this control can be a feasible alternative in PMSMs for railway traction applications.