Feedback linearization is used to regulate and shape the speed of a surface mount Permanent Magnet Synchronous Motor (PMSM). An extended high-gain observer, which is driven by the measured position of the PMSM’s rotor, is also used to estimate both the speed of the motor and the disturbance present in the system to recover the performance of feedback linearization. Two methods are presented to design the extended high-gain observer. The first method is based on the full model of the PMSM and the second method is based on a reduced model of the PMSM. The reduction of the model is made possible by creating fast current loops that allowed the use of singular perturbation theory to replace the current variables by their quasi-steady-state equivalent. The design of the speed controller and the extended high-gain observer is based on the nominal parameters of the PMSM. The disturbance is assumed to be unknown, and time-varying but bounded. Stability of the output feedback system is shown. Finally, simulation and experimental results confirm stability, robustness, and performance of the system.
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