Digital Sliding-Mode Sensorless Control for Surface-Mounted PMSM

In this work, a sampled-data model for surface-mounted permanent magnet synchronous motors (SMPMSMs) is proposed based on the symplectic Euler method. Then, based on the obtained model, a digital sliding-mode controller is designed for rotor velocity output tracking. Moreover, for rotor position and velocity and load estimation, a digital observer is designed. A separation principle is introduced in order to verify that the proposed controller can accomplish its task with estimated signals. Open-loop simulations predict that the sampled-data model obtained via the symplectic Euler method performs better than a model obtained with the classical explicit Euler method. Moreover, closed-loop simulations are carried on where the proposed controller is compared with a sampled continuous-time controller, where the controller here designed yields to better results even when the sampling period is increased. Finally, the performance of the proposed controller is verified by experimental tests.