Adaptive backstepping speed controller design for a permanent magnet synchronous motor

In the paper, a nonlinear adaptive speed controller for a permanent magnet synchronous motor based on a newly developed adaptive backstepping approach (PMSM) is presented. The exact input-output feedback linearisation control law is first introduced without any uncertainties in the system. However, in real applications, the parameter uncertainties such as the stator resistance and viscous constant and load torque disturbance have to be considered. In this case, the exact input-output feedback linearisation 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 linearisation approach is first used to compensate the nonlinearities in the nominal system. Then, a nonlinear adaptive backstepping control law and parameter uncertainty, and load torque disturbance adaptation laws, are derived systematically by using adaptive backstepping technique. Simulation and experimental results clearly show that the proposed adaptive scheme can track the speed reference signal generated by a reference model, successfully, and that the scheme is robust to the parameter uncertainties and load torque disturbance.