Nonlinear adaptive speed control for permanent magnet synchronous motors under unbalanced resistances

In this paper, we proposed nonlinear adaptive speed controller for permanent magnet synchronous motors in the presence of unbalanced phase winding resistances. An adaptive control is designed to compensate for the resistance unbalance in a-b-c frame dynamics. Estimated neutral voltage which is non-zero due to the unbalance is used for the adaptive control. It is proven using singular perturbation theory that the speed tracking error is globally asymptotically stable. Experiment with hardware-in-the-loop simulation (HILS) was performed for validating performance of the proposed method. We obtained that speed ripple was reduced with the proposed method.