Finite-time sliding mode speed control using an adaptive three-stage reaching law for PMSM

Area of Science:

• Control Systems Engineering
• Electrical Machines

Background:

• Sliding mode control (SMC) faces challenges in balancing finite-time convergence and chattering suppression for permanent magnet synchronous motors (PMSMs).
• Inertia mismatch can degrade control performance in PMSM systems.

Purpose of the Study:

• To propose a composite control scheme for PMSMs that achieves finite-time convergence and suppresses chattering.
• To enhance the robustness of PMSM control against parameter uncertainties and disturbances.

Main Methods:

• Development of an adaptive three-stage reaching law (ATSRL) with clamped exponential, state-dependent adaptive, and nonlinear power terms.
• Design of an enhanced super-twisting sliding mode observer (ESTSMO) for online lumped disturbance estimation and feedforward compensation.
• Integration of offline inertia identification using an extended sliding mode observer (ESMO) into the ESTSMO framework.

Main Results:

• The ATSRL adaptively adjusts reaching speed and reduces switching gain, enabling fast finite-time convergence and effective chattering suppression.
• The ESTSMO, incorporating offline inertia identification, significantly reduces disturbance estimation bias caused by inertia mismatch.
• Simulation and experimental results demonstrate the superiority of the proposed composite control scheme.

Conclusions:

• The proposed composite control scheme effectively addresses the trade-offs in PMSM control, offering improved performance.
• The integration of adaptive reaching laws and advanced observers provides a robust solution for PMSM applications.