Six-Step Operation With Multistep Predictive Control Using the Trapezoidal Method for Traction PMSM Drives

Model predictive control (MPC) has recently been considered for many permanent magnet synchronous motor (PMSM) drive applications. However, the conventional MPC presents insufficient overmodulation capability and, thus, cannot reach the six-step operation, which limits its application in the traction drive areas. This article proposes a novel MPC-based six-step operation scheme for the PMSM drive in traction applications. The prediction horizon is extended to the whole commutation period of the six-step operation, and a new average current-based objective function is introduced to determine the optimal commutation instants. To enhance the method's precision, a trapezoidal discretization method has been adopted in the long-horizon prediction. The effectiveness of the proposed method has been validated by detailed studies. The proposed method is demonstrated to have excellent current-tracking accuracy and fast dynamic response in the six-step operation, which is an advantage over the existing methods.