Robustness evaluation of SMO based speed-position estimation in BLDC motor

A robust sensorless back-EMF detection method for brushless dc (BLDC) motor drive system is presented in this paper. This estimated back-EMF is used to deduce the rotor position and the angular velocity of the rotor. Sliding Mode Observer (SMO) which is low sensitive to parameter variations is proposed to estimate the phase-to-phase trapezoidal back-EMF in a BLDC motor by the measurement of stator currents and voltages. The paper focuses the robustness evaluation of the Sliding Mode Observer to the variation of motor parameters.