Control of permanent-magnet synchronous machines using mechanical sensors and fast states observers

The problem of controlling the speed of permanent-magnet synchronous machines (PMSMs) using a single mechanical sensor is addressed. The design of the proposed control law is aimed at forcing the closed-loop system to have a linear structure with the capability of accommodating unknown loading conditions while adjusting a single control parameter. The electrical states of the PMSMs are estimated using a states observer with a backstepping-like structure with the advantage of having fast convergence rate via employing additional control parameters. The dynamics of the fast states observer and how it can be augmented to the dynamics of the PMSM model to form the closed-loop system are analyzed and simulation results are reported to illustrate the effectiveness of the proposed control system. Steady state accuracy and transient performance are investigated and a simple criterion for tuning the control parameters is introduced using a Lyapunov-based approach.