Adaptive sensorless control of high speed PMSM with back EMF constant variation

This paper deals with the adaptive sensorless control of high speed PMSM (Permanent Magnet Synchronous Motor) drives in turbo compressors with air bearings. The back emf (electromotive force) constant of PMSM varies with the operating motor temperature. The error of back emf constant has the dominant effect on the control performance of the current model-based sensorless control of PMSM. Therefore, this paper proposes the adaptive sensorless control method with the back emf constant estimator. The simulation and experimental results show that the proposed estimator yields the robust estimate of back emf constant and so the proposed adaptive algorithm works well under temperature variations in turbo compressor applications.