Torque and speed estimators to be implemented in a control strategy dedicated to TSTPI-fed BDCM drives

Abstract

Major improvements of the cost-effectiveness and of the reliability of electric machine drives could be gained through the integration of reduced structure inverters. Within this approach, the three-switch three-phase delta-shaped inverter (TSTPI) turns to be an interesting candidate. In a previous work, we have found that high performance of the TSTPI fed brushless DC motor drive could be gained following the implementation of a dedicated control strategy including a torque loop in order to reduce torque ripple during sequence-to-sequence commutations. Therefore, beyond the speed, the electromagnetic torque estimation turns to be a necessity. The paper proposes BDCM speed and torque estimators which are developed taking into account the waveforms of the phase back-EMFs and the outputs of six-pulse encoder associated to the motor.