Improvements in direct torque control of induction motor for wide range of speed operation using fuzzy logic

Abstract

The main objective of this paper is to ameliorate the performance of direct torque control of induction motor for a wide range of speed control using fuzzy logic. The major drawbacks of conventional direct torque control are high torque, flux ripples and poor dynamic response at low speed. In this paper the CDTC is improved by fuzzy logic switching controller and fuzzy logic duty cycle controller. In FDTC with FDCC the selected voltage vector is applied only for the duty cycle time period (δ) determined. Simulation results validate that the proposed scheme shows improved dynamic performance of the drive for a wide range of speed (0–100 rad/s) and the torque and flux ripples are reduced by 90% compared to CDTC. Keywords: Direct torque control (DTC), Fuzzy Direct Torque control (FDTC), Fuzzy duty cycle controller (FDCC), Induction motor (IM), Membership function (MF)