Hierarchical Non-Singular Terminal Sliding Mode Control with finite-time disturbance observer for PMSM speed regulation system

Based on finite-time disturbance observer (FTDOB) and Hierarchical Non-singular Terminal Sliding Mode Control (HNSTSMC), a Practical Hybrid Robust Control (PHRC) for the PMSM speed regulation system is developed in this article. Firstly, to minimize the speed tracking error of the stabilization time and achieve global fast convergence, the HNSTSMC method is proposed. Secondly, to further reduce the chattering of the HNSTSMC method, the FTDOB utilizing the sign function is developed. Moreover, the proposed FTDOB can quickly adjust the system state from the initial state to the desired state in a limited time. Then, the estimated overall disturbance through the FTDOB can be compensated into the HNSTSMC controller. The PHRC controller is tested and compared with other controllers. Experiment results display that the PHRC controller exhibits superior anti-disturbance capability and fast response performance.