Stability study of a permanent magnet synchronous motor sensorless vector control system based on extended EMF model

Abstract

A simplified sensorless vector control system is derived by using the extended electromotive force (EMF) model. By using a steady-state voltage equation approximately, the rotor speed and position are computed from the output voltage of a γ-axis proportional plus integral (PI) current controller with decoupling control. A linear model is proposed for the small perturbation around a steady-state operating point. The system stability is discussed in terms of the trajectories of the system matrix eigenvalues for speed estimation and control parameters. The comparison between the simulation results obtained using a nonlinear model and the experimental results validates the derived system.