An Axial Gap Bearingless Motor Drive System with Non-linear Disturbance Observers-Based Robust Control

In this study, a control system for a permanent magnet axial gap bearingless motor (AGBM) with a non-salient pole rotor is given using a non-linear disturbance observer-based robust control. In the proposed control strategy, low-pass filters are integrated into each virtual control input, and a powerful backstepping controller with integrated tracking error action is utilized. An integral backstepping control (IBSP) integrator is added to improve the system’s robustness to parameter uncertainties and external disturbances. The low pass filter of dynamic surface control (DSC) based on an integral backstepping algorithm is adopted, from which the proposed control strategy improves steady-state accuracy and eliminates the derivative explosion phenomenon. Furthermore, non-linear lumped disturbance observers (NLDO) are used for axial displacement and rotation speed control loop to improve system stability by minimizing the impact of disturbances such as parameter uncertainties, unknown load torque and force, and unmodeled dynamics acting on the control system. Finally, the effectiveness, feasibility, and robustness of the proposed approach are demonstrated through simulation evaluation. The root means square deviation (RMSD) of axial displacement and angular velocity error are used to compare the presented techniques.