Ultra-Local Model-Based Adaptive Enhanced Model-Free Control for Pmsm Speed Regulation

Conventional model-free control (MFC) is widely used in motor drives for its simplicity and model independence, yet suffers from inaccurate disturbance estimation and parameter mismatches. This paper proposes an adaptive enhanced model-free speed control (AEMFSC) scheme for permanent magnet synchronous motors (PMSMs) that integrates a nonlinear disturbance observer (NDO) with PD control to improve disturbance rejection and tracking performance. The method eliminates steady-state errors, reduces speed overshoot, and achieves faster settling compared to conventional approaches. An online parameter identification technique adapts the input gain α to varying loads, while an algebraic framework optimizes initial α selection. Experimental results confirm enhanced robustness against load and parameter variations.