Sensorless Three-Level Direct Torque Control of a Five-Phase PMSM Using Sliding Mode Observer

In this paper, a three-level direct torque control (DTC) structure is presented to control a sensorless five-phase permanent magnet synchronous machine using sliding mode observer (SMO). The proposed structure can decrease considerably the torque and stator flux ripples. On the other hand, the elimination of the speed sensor reduces the hardware complexity, size and cost, and increases the reliability of the multiphase drive. In this context, SMO is used to estimate the rotor speed and stator flux as well as electromagnetic torque. Finally, simulation results show clearly the effectiveness of the proposed structure compared to conventional two-level DTC in terms of ripple reduction.