Passivity-based control of synchronous motors

Due to its great potential value in theory and application, nonlinear control strategies of synchronous motors (SM), especially passivity-based control (PBC) methods, have been a focus in the literature. A PBC strategy for SM with time-varying load torque to track flux and speed trajectories is proposed in this paper. The key point of this method is the identification of terms, known as workless forces, which appear in the dynamic equations of SM but have no effect on the energy balance equation of the closed loop. PBC combined with rotor currents estimator not only reserves the advantages of PBC such as nonexistence of singularity, but also rejects the flux and speed tracking error caused by stator and rotor resistance variation. This algorithm simplifies the control structure and enhances the robustness of the control system. The feasibility and effectiveness is testified by the experimental results based on dSPACE.