Speed estimation algorithms for sensorless control of PMSM

The sensorless vector control of Permanent Magnet Synchronous Motor (PMSM) drive is presented in this paper. The flux and instantaneous reactive power based sensorless speed estimation algorithms are designed and analyzed. In the flux based speed estimation algorithm, the estimated speed can be obtained directly from the flux and current relations. Mainly the speed error occurs between the estimated and the actual speed because of the errors in measurement of the motor parameters and the sensing errors of the line currents and input voltages. To minimize the speed error, the estimated speed error is compensated by the instantaneous reactive power. The reactive power based estimation algorithm improves the performance of the drive system by avoiding integrator's drift problem compared to flux estimation algorithm. The algorithms was verified by simulation in MATLAB /SIMULINK using SVPWM inverter.