Robust Flatness Control with Extended Luenberger Observer for PMSM Drive

This paper proposes a flatness control scheme for controlling the speed/torque of a permanent magnet synchronous motor (PMSM). As the flatness control, its performance largely depends on the accuracy of model parameters. So, to improve the performance of the flatness control, extended luenberger observer is utilized to estimate the parameter of PMSM such as a load torque disturbance and a stator resistance (represent losses in an inverter and PMSM) by means of its voltage drop, which has advantages over conventional observers such as independence from mathematical model accuracy, robustness, and good dynamic performance. Also, only observer gains need to be tuned and the tuning process is not complicated because the gains are determined by the desired observer bandwidth. To validate the proposed method, a hardware system is realized in a laboratory, and digital estimation is accomplished with a dSPACE controller DS1104 platform. Simulation and experimental results with a small-scale PMSM of 6-pole, l-kW, and 3000 rpm in a laboratory corroborate the excellent control scheme during a motor-driven cycle.