Sliding Mode Observer based Sensorless Current Hysteresis Controller for PMBLDC Motor Drive

Abstract

This paper develops the sensorless control system for PMBLDCM. The sensorless operation is based on a sliding mode observer. The hysteresis controller has been implemented for current control of PMBLDCM drives system. The hysteresis current control is utilised to account for the phase error of stator phase back EMF. With this approach, the switching pattern for power switches of three phase inverter is developed to drive the PMBLDCM. The signum function based sliding mode observer is used to estimate the rotor angular speed. The overall torque due to the external forces enclosed to the PMBLDCM has been taken as disturbances to the system. Further, such disturbances are estimated to achieve the rotor orientation of PMBLDCM in the complete supply intervals. The motor speed is derived with the obtained rotor position of PMBLDCM drive. The phase-to-phase trapezoidal back-EMF for sensorless activity is calculated by SMO, which is merely sensitive to parameters variance. The stability analysis has been justified by designing sliding surface and the error dynamics constraints is estimated to minimise the disturbances in estimated parameters. The results confirm the feasibility and efficacy of the proposed sensorless SMO method based hysteresis current control of PMBLDCM drive.