Ibrahim Mohd Alsofyani and Kyo-Beum Lee, "Modified Frequency Carriers for Improving DTC with Constant Frequency Torque Controller of Induction Machines," in Proc. CENCON Conf., Oct. 2017, pp. 128–132. > Paper

Constant frequency torque controller-based direct torque control (CFTC-DTC) of an induction motor (IM) drive has been widely

studied for two- and multi-level voltage source inverter recently. This control method suffers from the limitation of torque loop

bandwidth since the frequency carriers are generated by the same software used for system control. The performance of CFTC

depends mainly on the torque loop bandwidth; the higher the bandwidth, the better the performance of CFTC-DTC drive. This paper

proposes a modification on the frequency carriers of CFTC to increase the torque loop bandwidth. Unlike the conventional CFTC, the

carriers of proposed CFTC are generated by ramp waveforms resulting in 50 % increase of the carrier frequency. The simulation

results prove the effectiveness of the proposed drive system.