Improving flux regulation of DTC induction motor drive by modifying the index to the FPGA-based lookup table

DTC is known for its fast torque response, robustness against parameter variation and simple implementation. The performance of DTC drive, however, deteriorates at low speed due to its poor flux regulation. This paper proposes a technique to improve the flux regulation, and it only requires minor changes to the index of the look-up table. With this method, the simple structure of the DTC is retained and the same look-up table can be used. Experimental results are presented to show the effectiveness and viability of the proposed method. It is shown that flux regulation at low speed is improved and rated flux can be established even at zero speed; improvement in the flux regulation significantly improves the torque dynamic.