Position sensorless control of PMSM using sliding mode observer with two-stage filter

The premise of realizing the vector-control of permanent magnet synchronous motor (PMSM) lies in obtaining the accurate information of speed and rotor position. A sliding mode observer based on two-stage filter is designed to apply for estimation of rotor position and speed of PMSM. The output of first stage filter provided feedback to the current observer, and the output of second stage filter was used to calculate the rotor position, and the piecewise linear compensation was used for the position estimation error compensation. The position sensorless control system of PMSM using sliding mode observer based on two-stage filter was given, the current observation of sliding mode observer, back-EMF (electromotive force)observer, position and velocity estimation, load disturbance and dynamic process were simulated to verify the feasibility of sliding mode observer algorithm. Finally an experimental platform of position sensorless control system was built, the boot process, the back-EMF observer, position and speed estimation and variable parameters control were studied to verify the sliding mode observer algorithm. Simulation and experimental results show that the sliding mode observer can quickly and accurately track the rotor position and speed, and the system is with fast response and robustness.