A MRAS-based stator resistance and speed estimation for sensorless vector controlled IPMSM drive

• In this paper, model reference adaptive system technique has been used for speed estimation in sensorless speed control of synchronous motor.
• This paper studies a novel MRAS observer, considering the saliency of PMSM. The MRAS technique is simple and it requires less computation time.
• A novel stator resistance estimator is incorporated into the sensorless drive to compensate the effects of stator resistance variation.
• The real time implementation concept on the digital signal processor (DSP) board of the VFOC design and SVPWM inverter technique are illustrated.
• Results show that the proposed MRAS technique can satisfactorily estimate the position and speed of PMSM with saliency.

In this paper, model reference adaptive system (MRAS) technique has been used for speed estimation in sensorless speed control of interior permanent magnet synchronous motor (IPMSM) with space vector pulse width modulation (SVPWM). Most of the current researches studying the MRAS technique are based on non-saliency PMSM model and ignore the difference between d- and q-axes inductances. This paper studies a novel MRAS observer, considering the saliency of PMSM. However, this sensorless speed control shows great sensitivity to stator resistance and system noise, particularly, during low-speed operation. A novel stator resistance estimator is incorporated into the sensorless drive to compensate the effects of stator resistance variation. A stability-analysis method of this novel MRAS estimator is shown. Stable and efficient estimation of rotor speed at low region will be guaranteed by simultaneous identification of IPMSM. The stability of proposed stator resistance estimator is checked through Popov's hyperstability theorem. The proposed observer is experimentally tested using a 1.1-kW motor drive; stable operation at very low speeds under different loading conditions is demonstrated. The real time implementation concept on the digital signal processor (DSP) board of the VFOC design and SVPWM inverter technique are illustrated. Results show that the proposed MRAS technique can satisfactorily estimate the position and speed of PMSM with saliency.