<p>Speed control of permanent magnet synchronous motors (PMSM) is one of the most challenging issues due to their wide application. More precisely, increasing accuracy, dealing with uncertainties and disturbances, and controlling the rate of damping changes are among the important challenges of controlling the speed of these motors. This article tackles these challenges and presents a nonlinear state feedback control method for PMSM motor speed control. The control method presented in this article includes a linear part and a nonlinear part. In the linear part of the controller, a controller is calculated in such a way that the performance of L2-gain is established. In other words, in this section, the gain of the controller is determined in such a way that the neutralizer can deal with disturbances and uncertainties. In this section, finally, the problem is replaced by solving a linear matrix inequality (LMI) problem, which solves the gain of the controller. In the second part, i.e., the nonlinear part of the gain controller, this controller is calculated in such a way that the damping rate changes are adjusted. Summing the controllers extracted from these two parts gives a final controller that resists the control loop against disturbances and uncertainties, regulating the rate of damping changes. The productivity of the recommended method has been reviewed during a series of practical tests in the laboratory; the results confirm the good performance of the recommended method in speed control of PMSM motors.</p>