A robust method for flux weakening operation of DTC induction motor drive with on-line estimation of the break-down torque

A method for the flux weakening operation of DTC induction motor drives is proposed. The flux reference is adjusted on the basis of the torque error, thus determining a spontaneous flux weakening. For implementing this algorithm, it is necessary to estimate the maximum torque that the induction machine is able to generate at any speed. The main features of the proposed system are little dependency on machine parameters and smooth transition into and out of the flux weakening operation mode. Experimental tests demonstrate the effectiveness of the control scheme