LAUSR

This paper presents a speed observer design based on backstepping and sliding mode approaches. The inputs to the observer are the stator current and the voltage vector components. This observer structure is extended to the integrators. The observer stabilizing functions contain the appropriate sliding surfaces which result from the Lyapunov function. The rotor angular speed is obtained from the non‐adaptive formula with a sliding mode mechanism. It allows improvement of the robustness of parameters uncertainties and the zero rotor speed to work (near to the unobservable region). In the sensorless control system, the classical first‐order sliding‐mode controllers are applied with the transformation of the multi‐scalar variable. The proposed control system structure can be named full‐decoupled due to multi‐scalar variables transformation and the feedback control law obtained from the Lyapunov theorem. The theoretical derivations are verified in experimental waveforms. The sensorless control system's robustness is verified in the experimental investigations by using the nominal machine parameters uncertainties method.