Sensorless adaptive backstepping speed tracking control of uncertain permanent magnet synchronous motors

This paper proposes a novel sensorless speed tracking control scheme for the permanent magnet synchronous motors (PMSM) with uncertain parameters. An angular speed observer is designed to achieve the purpose of sensorless speed estimation, and then a speed tracking controller is developed with the adaptive backstepping technique to deal with the parameter uncertainties and load variation in the PMSM system. The stability of the whole closed loop system is guaranteed under Lyapunov criterion. Performance of proposed controller is investigated under different dynamic operating conditions such as step changes in commands, step changes in load, and parameter variations. The results indicate the effectiveness of the scheme in terms of the speed tracking ability and robustness against parameter variations.