A novel finite-time control with q -axis current constrained based on time-varying second-order nonlinear disturbance observer is investigated to improve the performance of overcurrent protection and disturbance rejection for permanent magnet synchronous motor (PMSM) system. In general, the hardware could be damaged by a large transient current for achieving high-precision tracking performance when PMSM starts up. To this end, a speed-current single-loop control with q-axis current constrained is constructed by a novel finite-time controller for speed regulation of the PMSM system, which can balance well between the overcurrent protection and dynamic performance. The estimated peak generated by the high gain to ensure a precise accuracy will be integrated into the control system at the initial moment in the traditional nonlinear disturbance observer. Taking this into account, parameter uncertainties, nonmodeled dynamics, and estimated peak at the initial moment of the PMSM system are estimated by a time-varying second-order nonlinear disturbance observer. Finally, rigorous stability analysis is established for the proposed composite strategy. Comparative simulations and experiments are designed on proportion integration differentiation, sliding mode control (SMC), and the proposed method. Results demonstrate that the proposed method has better robustness and overcurrent protection property.

Combining the feedback of predictive function control and the feedforward of extended state observer, a composite control strategy is proposed for the permanent magnet linear synchronous motor (PMLSM). The mathematical model of the PMLSM vector control system is established based on the basic structure and operation mechanism of PMLSM. Then, a speed regulator based on predictive function control (PFC) is designed to improve the speed tracking performance of the PMLSM drive system. The state and disturbance of the PMLSM system estimated by the extended state observer (ESO) transferred to the PMLSM drive system, and the robustness of the drive system will be improved. Comparative simulation and experiment results show that the proposed method has better speed tracking performance and disturbance rejection property.

To simplify the control structure and increase the anti‐disturbance performance, a non‐cascade control method for a permanent magnet synchronous motor drive system is studied, which regulates the speed and current in one loop. The proposed control scheme is a composite control strategy including speed‐current single‐loop feedback control and feedforward compensation based on disturbance estimation. A feedback controller based on backstepping sliding mode control is proposed to realise speed‐current single‐loop. Disturbance estimated by a third‐order extended state observer is used in feedforward compensation. Rigorous analysis of stability is conducted to validate the convergence of the control scheme. Simulation and experimental results demonstrate that the proposed control scheme achieves a better speed tracking performance and disturbance rejection property over proportional–integral–derivative and sliding mode control.

A non-singular terminal sliding mode control based on finite time observer is designed to achieve speed direct control for the permanent magnet synchronous motor (PMSM) drive system. Speed and current are regulated in one loop under the non-cascade structure, taking place of the cascade structure control method in the vector control of PMSM. Based on the second-order speed function of the PMSM, the disturbance and parameters uncertainties are estimated by the designed finite time observer (FTO), and compensate to the drive system. The estimated value of the finite time observer will converge to the actual disturbance value in a finite time. A second-order non-singular terminal sliding mode controller is proposed to realize the speed and current single-loop, which can track the reference speed and reference current in a finite time. Rigorous stability analysis is established. Comparative results verified that the proposed method has faster speed tracking performance and disturbance rejection property.

A non-singular terminal sliding mode control based on finite time observer is designed to achieve speed direct control for permanent magnet synchronous motor (PMSM) drive system. Speed and current are regulated in one loop under the non-cascade structure, taking place of the cascade structure control method in the vector control of PMSM. Based on the second-order speed function of the PMSM, the disturbance and parameters uncertainties are estimated by the designed finite time observer (FTO), and compensate to the drive system. The estimated value of the finite time observer will converge to the actual disturbance value in a finite time. A second-order non-singular terminal sliding mode controller is proposed to realize the speed and current single-loop, which can track the reference speed and reference current in a finite time. Rigorous stability analysis is established. Comparative results verified that the proposed method has faster speed tracking performance and disturbance rejection property.