Abstract
An identity state observer for the smooth-rotor permanent-magnet synchronous motor is derived which reconstructs the electrical and mechanical states of the motor from current and voltage measurements. The observer operates in the rotor frame and estimates direct and quadrature stator currents, rotor velocity, and rotor position. Since the rotor position is estimated, the rotor reference frame is approximated using the latest rotor position estimate. The motor dynamics and the transformation into the estimated rotor frame are nonlinear and thus the observer and observer error dynamics are nonlinear. Therefore, small signal stability is analyzed from a linearized model. Simulations including realis-tic measurement disturbances are used to investigate the global stability and accuracy of the observer.© (1987) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.