Adaptive backstepping - based controller design for speed sensorless SPMSM using sliding mode observer

In this paper, an adaptive backstepping (ABS) controller is first designed for speed sensorless surface permanent magnet synchronous motor (SPMSM) drives. The ABS controller can secure the system stability and its robustness against the parameter uncertainties an external load torque disturbance. Among the parameters estimate, it is shown that the estimated error in stator inductance, stator resistance and rotor magnetic flux converge asymptotically to zero if the system persistency excitation (PE) of condition is satisfied. The PE condition is satisfied if a low amplitude, low frequency ac signal is superimposed to the d-axes reference current. Then a back EMF sliding mode observer (SMO) is employed in order to detect the rotor speed and position. The proposed control approach is tested by simulation. Computer simulation results obtained, confirm the validity and effectiveness of this control approach.