Sensorless control for PMSM using model reference adaptive system

Summary This paper presents a model reference adaptive system (MRAS) method to estimate the position and speed of permanent magnet synchronous motor (PMSM) by considering the error between real and estimated rotor position values. A state equation of PMSM in synchronous d‐q reference frame is expressed based on the estimated speed and nominal parameter of the PMSM. The derived MRAS adaptation scheme to estimate the rotor position and speed of the main objective is to minimize the errors between the derivatives of d‐q axis currents of the real and model systems. The proposed method has been tested for various speed and load torque conditions. The experimental results show good performance and accurate speed‐tracking capability when it is compared with the sliding mode observer (SMO). The main contributions are highlighted as follows: Reference adaptive system (MRAS) is designed for a PMSM. A state equation of PMSM in synchronous d‐q reference frame is expressed based on the estimated speed and nominal parameter of the PMSM. The main feature of this method is to minimize the errors between the derivatives of d‐q axis currents of real and model systems. The proposed method has been tested for various speed and load torque conditions.