Robust current tracking control of permanent magnet synchronous motor under parametric uncertainty by coupling effect

The field-oriented control method is widely used in permanent magnet synchronous motor control due to its decoupling of the d – q axis currents in the nominal model. However, parametric uncertainties caused by temperature variations and external disturbances inevitably degrade the decoupling performance and current tracking accuracy. This paper develops a bounded-uncertainty model to describe the resulting coupling effect, which is quantitatively identified using experimental data. An H ∞ state-feedback controller is then proposed to achieve robust current tracking under model uncertainty and disturbances. The controller synthesis is formulated via linear matrix inequalities, guaranteeing prescribed convergence rates and H ∞ disturbance rejection. Simulations and experiments demonstrate that the proposed method ensures fast and independent tracking of d – q currents under parameter variations and disturbances, outperforming conventional proportional-integral-derivative (PID) and linear quadratic regulator (LQR) controls in robust performance. The novelty of this paper lies in the experimental quantification of bounded parametric uncertainty and its induced cross-coupling, together with a linear matrix inequality-based H ∞ state-feedback design that guarantees prescribed convergence rates under both parametric uncertainty and external disturbances.