Publication of Little Lion Scientific R&D, Islamabad PAKISTAN NONLINEAR ADAPTIVE BACKSTEPPING CONTROL OF PERMANENT MAGNET SYNCHRONOUS MOTOR (PMSM)

In this paper, a nonlinear adaptive speed controller for a permanent magnet synchronous motor (PMSM) based on a newly developed adaptive backstepping approach is presented. The exact, input-output feedback linearization control law is first introduced without any uncertainties in the system. However, in real applications, the parameter uncertainties such as the stator resistance and the rotor flux linquage and load torque disturbance have to be considered. In this case, the exact input-output feedback linearization approach is not very effective, because it is based on the exact cancellation of the nonlinearity. To compensate the uncertainties and the load torque disturbance, the input-output feedback linearization approach is first used to compensate the nonlinearities in the nominal system. Then, nonlinear adaptive backstepping control law and parameter uncertainties, and load torque disturbance adaptation laws, are derived systematically by using adaptive backstepping technique. The simulation results clearly show that the proposed adaptive scheme can track the speed reference s the signal generated by a reference model, successfully, and that scheme is robust to the parameter uncertainties and load torque disturbance.