Real-time PI controller based on pole assignment theory for permanent magnet synchronous motor

In order to deal with the uncertainties of permanent magnet synchronous motor, the moment of inertia, viscous damping coefficient and load torque are online identified simultaneously based on recursive least-square (RLS) estimator, which is composed of RLS estimator and a torque observer. Then, a novel self-tuning PI controller is real-time designed according to the identified parameter based on pole assignment theory, to match the time-domain command tracking specification. The moment of inertia and viscous damping coefficient identified are used to update the parameters of the observer, so the observer can observe the load torque well and truly when the parameters of the system varied severely. Then, the observed disturbance torque is fed forward, to increase the robustness of the synchronous motor drive. The simulation results show that the method not only enhances the fast tracking performance, but also increases the robustness of the synchronous motor drive.