Mechanical sensorless PMSM drive system based on direct torque control in M-T frame synchronized with stator flux-linkage vector

This paper proposes a mechanical sensorless drive system based on direct torque control for permanent magnet synchronous motor. In the proposed system, the whole control system works in a rotating reference frame that is synchronized with the stator flux linkage vector. The armature voltage in the stationary reference frame does not required for the flux estimation. In addition, the proposed system includes maximum torque per ampere (MTPA) and flux-weakening controls for wide-speed-range operation. A novel MTPA model is used for the reference flux calculation. Both simulation and experimental results show the effectiveness of the proposed system.