A novel direct torque control for induction motor drive system with low torque ripple and current distortion utilising FPGA

Abstract

The conventional Direct Torque Control (DTC) is known to produce quick and robust response in ac drives. However, during steady state, notable torque and current pulsations occur. They are refl ected in speed estimation, torque response and also produce acoustic noise. In this paper, a novel Space Vector Modulated Direct Torque Control (SVM-DTC) with Low Pass Filter (LPF) for induction motor drive system is proposed, which features low torque ripple, low current distortion and fixed switching frequency. The proposed scheme has been implemented on the Xilinx Spartan 3E FPGA, both simulation and experimental results show that the proposed system can dramatically improve the steady state performance while preserving the dynamic performance of the conventional DTC.