Digital control of a permanent magnet synchronous motor drive without mechanical sensors

The permanent magnet synchronous motor (PMSM) is preferable for servo appli cations and domestic appliances. where high operating efficiency, low power loss, and ease of maintenance are required; however, the cost of the PMSM drive system is relatively high If mechanical sensors are used to measure t he rotor position. In this paper, a minimal-order position observer is appl ied to the PMSM drive. As the rotor position is estimated with the measurem ents of the phase currents and line voltages, the expensive save mechanical transducers are eradicated. Consequently, the cost of the whole system is reduced and the reliability increased. A number of meaningful issues have b een addressed to enforce the theoretical basis of this approach, including the derivation of the discrete plant model, discussion of the modeling erro r and its influence on state estimation, and stability analysis of the comp lete system under model uncertainties. Simulation and experimental results under different operating conditions are presented, demonstrating the poten tial to apply the proposed control and estimation. techniques to practical applications.