Improved torque response of induction motor drive using direct torque control technique applying Fuzzy Logic Control

In this paper a new control technique is proposed by using fuzzy logic control for direct torque control of induction motor. Contemporarily, induction motor is most commonly used for variable speed drive application because of following advantages over DC drives: low maintenance cost, high efficiency; robust and rigged operation; and can be used in any environmental conditions. Field oriented control is one of the strategy for control of induction motor and has been widely acknowledged in drive industry. But due to its complexities such as sensitivity to parameter variation, tuning, temperature and tedious vector calculations, direct torque control technique is gaining importance. Large torque ripples occur in induction motor, based on conventional direct torque control system. For this problem of DTC, fuzzy control theory is proposed and executed. A modified look up table for the selection of switching vectors is proposed. Space vector modulation technique is used to synthesize the inverter output voltages. Fuzzy controller system is applied for 1.5kW of motor which selects appropriate voltage space vector for minimum torque ripples. The proposed scheme is simulated on the platform of Matlab/Simulink.