In this contribution, a cascaded control strategy is presented for a permanent magnet synchronous motor (PMSM) that compensates for model nonlinearities and enables an accurate as well as robust trajectory tracking. The proposed strategy comprises the combination of an inversion-based current control, one of two alternative second-order sliding mode control approaches (SMC) and an extended Kalman filter (EKF). The reference values for the inversion-based current controllers are calculated by a Maximum Torque Per Ampere (MTPA) strategy in an outer control loop. As second-order SMC approaches are investigated: one design based on an integrator extension of the control input, whereas the other is given by a hybrid twisting control. Both alternatives mitigate undesired chattering while the EKF yields smooth estimates for both the state variables and a lumped disturbance torque from noisy measurements. Moreover, the robustness of the overall control structure is increased, chattering effects are reduced and unknown disturbances as well as parameter uncertainty are addressed by combining second-order sliding mode control with estimator-based disturbance compensation. The potential of the proposed nonlinear control strategy is pointed out by successful simulation studies.