An Improved Flux Observer for Sensorless Permanent Magnet Synchronous Motor Drives with Parameter Identification

  • Lin, Hai (Department of Automation, School of Electronic and Control Engineering, Chang'an University) ;
  • Hwang, Kyu-Yun (Department of Electronics, Electrical, Control and Instrumentation Engineering, Hanyang University) ;
  • Kwon, Byung-Il (Department of Electronic Systems Engineering, Hanyang University)
  • Received : 2012.03.21
  • Accepted : 2012.12.11
  • Published : 2013.05.01


This paper investigates an improved stator flux linkage observer for sensorless permanent magnet synchronous motor (PMSM) drives using a voltage-based flux linkage model and an adaptive sliding mode variable structure. We propose a new observer design that employs an improved sliding mode reaching law to achieve better estimation accuracy. The design includes two models and two adaptive estimating laws, and we illustrate that the design is stable using the Popov hyper-stability theory. Simulation and experimental results demonstrate that the proposed estimator accurately calculates the speed, the stator flux linkage, and the resistance while overcoming the shortcomings of traditional estimators.


Permanent magnet synchronous motor;Observer;Stator flux linkage


Supported by : National Research Foundation of Korea


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