<p>Speed control of permanent magnet synchronous motors (PMSMs) remains a significant challenge in both past and current research. Model uncertainties and sudden load shifts negatively affect the accuracy of speed control of these motors. This paper addresses these issues and presents a new control structure drawing on state-feedback control and the Luenberger estimator. In this research, a state-feedback controller is designed to account for uncertainties, enhancing robustness. Besides, the load torque is estimated online by an estimator drawing on Luenberger and referred to the controller to increase the system’s robustness to sudden load changes. Conversely, during the design of this control structure, the H infinity performance is guaranteed to remove the effect of disturbance on the speed tracking error. Finally, the problem has become a linear matrix inequality (LMI), so that by solving it, the design parameters can be extracted and adjusted to their best state. The proposed strategy was validated through two practical laboratory tests, demonstrating high accuracy and effectiveness compared to other methods.</p>