A finite control set model predictive direct torque control for the PMSM with MTPA operation and torque ripple minimization

In this paper, a Lyapunov based finite control set model predictive direct torque control for the permanent magnet synchronous machine (PMSM) is proposed. In the proposed control scheme, the finite control set prediction and the Lyapunov theory are combined to minimize the torque ripple. The 8 voltage vectors of the 2-level converter are utilized as a finite control set for the torque prediction of the PMSM. A cost function considering the torque error, the Maximum Torque per Ampere (MTPA) operation and the current limitation is introduced. Comparing to the conventional finite control set predictive control, the dominant part of the cost function is utilized as a Lyapunov function to estimate the duty cycle of each voltage vector. An optimum voltage can be obtained by the optimum voltage vector from the 8 vectors and their duty cycles. A small sampling frequency and a fixed switching frequency can be realized when compared to the conventional finite set model predictive control. In the end, the simulation and experimental results validate the performance of the proposed control scheme.