Study of position sensorless control based on sliding mode observer

In this paper, permanent magnet synchronous motor was the controlled object. According to its mathematical model, a new position observing system was designed based on sliding mode theory, which used sliding mode observer instead of the traditional position sensor. This design replaced the traditional switch functions with continuous saturation functions in the sliding mode observer, and the result showed the high frequency noise signal could be reduced effectively. Finally, by the verification of dSPACE experimental platform and the real-time observing of Control Desk environment, the results proved the design of the new sliding mode observer could not only accurate observing position signal, but also had a high robustness for the system parameter variation and external disturbance.