Speed-Sensorless DTC of a Matrix Converter Fed Induction Motor Using an Adaptive Flux Observer

This paper aims at combining some of the best features of an available induction motor (IM) drive system while introducing a simplified adaptive flux estimation algorithm for sensorless operation. The use of a matrix converter (MC) is proposed to achieve improved source side power quality and input power factor correction of an IM drive. Direct torque control (DTC) of an IM is realized through appropriate switching of the MC and the control strategy is implemented with speed-sensorless operation by using a relatively simplified adaptive flux observer. DTC through speed and flux estimation is realized in the stationary reference frame. Primarily, three objectives are achieved, viz. speed regulation while directly controlling the motor torque (and flux), improved source side power quality owing to the use of MC, and substantially simplified sensorless estimation strategy. Additionally, economic benefits are also achieved owing to negligible energy storage requirements of the drive and sensorless operation.