Adaptive Sensorless Control of PMSM using Back-EMF Sliding Mode Observer and Fuzzy Logic

This article presents a sensorless control system of PMSM (Permanent Magnet Synchronous Motors)using a back-EMF (back electromotive force) sliding mode observer and a main and correction fuzzy logic controllers to adapt continuously the adjustment parameters K
_p
and K
_i
of the speed controller part of the FOC (Field Oriented Control) strategy and achieving superior adjustment performance without overshooting and reduced rising and settling time. In order to achieve superior performance, a second fuzzy controller is proposed which, besides the error and the error derivate of the rotor speed as inputs will also take into account the load torque (an estimate of it) to adjust the adjustment parameter K
_p
differently depending on the load torque size, but also on the dynamic or stationary regime that occurs during the required speed profile tracking.