Nonlinear speed tracking control for sensorless PMSMs with unknown load torque: From theory to practice

In this paper the speed tracking control problem for sensorless (nonsalient-pole surface) permanent magnet synchronous motors (PMSMs) with unknown load torque is addressed. Simulation and experimental results are presented for the first nonlinear adaptive control which (i) relies on a closed loop stability proof using nonlinear stability tools; (ii) feeds back stator current and voltage measurements only without using non-robust open loop integration of motor dynamics. Satisfactory performances are obtained in practice in conditions which can be inferred by deeply analyzing the reported theoretical analysis.