A novel MRAS current-based sensorless vector controlled PMLSM drive for low speed operation

Abstract

A novel model reference adaptive system (MRAS) current-based estimator for permanent magnet linear synchronous machines has been developed to estimate the speed and stator resistance during low speed operation. The inclusion of stator resistance estimation Is crucial because the sensorless drive's stability is sensitive to any stator resistance mismatch particularly at low speed operation. The estimator is derived according to Lyapunov's second theorem to ensure stability of the sensorless drive under all operating conditions. Stability of the proposed estimator Is always well preserved even at motoring and regenerating regions, which is verified by extensive simulations and experimental results. Detailed study on the stability of the MRAS current-based estimator has been carried out to prove the stability of the designed estimator for various operating modes.