Fuzzy Logic Direct Torque Control Research Articles

Fuzzy logic direct torque control of induction motor for photovoltaic water pumping system

This study presents a fuzzy logic direct torque control for induction motor to be used in photovoltaic (PV) water pumping system. The system is intended to be less expensive and simple while maximizing PV array power utilization. For this purpose, a smart technology based on fuzzy logic controller (FLC) has been implemented to track the maximum power which has been successfully used in solar water pumping systems under different irradiance levels. Next, to alleviate the disadvantages of standard DTC, we chose fuzzy direct torque control (FDTC) for induction motors driving a centrifugal pump. Furthermore, this study includes the usage of IP with antiwindup and slide mode speed controller (SMC) instead of the traditional proportional-integral speed controller. Finally, the induction motor (IM) speed has been optimized with an optimum speed control in order to maximize the pump’s hydraulic parameters. The FDTC, with its SMC outperforms the photovoltaic pumping system (PVPS) in terms of dynamic performance and robustness. To develop a full simulation model of the proposed PVPS configuration under various climate conditions, MATLAB environment and associated Simulink are used.

Minimization of torque ripple of direct-torque controlled induction machines by improved discrete space vector modulation

In this paper, discrete space vector modulation (DSVM) technique for induction machine drives is developed, and then a fuzzy logic direct torque control (DTC) scheme based on the proposed DSVM technique is presented. In DSVM technique, new voltage vectors are synthesized by applying three standard voltage space vectors for three equal time intervals at each sampling period. Rearranging the sequence of the three voltage space vectors does not change final synthesized voltage vectors, but has an influence on torque ripple. By comparing torque waveforms in one sampling period, an analysis is carried out to determine the influence. Based on the analysis, new switching tables used in DSVM-DTC are defined. In the switching tables, the three components of each synthesized voltage vector are arranged in optimized sequence. Finally, a fuzzy logic controller is designed to select synthesized voltage vectors. Its control rules are established based on the proposed switching tables. The proposed scheme is verified by simulations. Simulation results show that a reduction of torque ripples is achieved in a whole speed range.

Improving direct torque control by meansof fuzzy logic

Investigations are carried out on a fuzzy logic direct torque control system, which not only reduces the torque ripple, but also reduces the reactive power taken from the mains by choosing the optimum reference flux value. Additionally, this fuzzy controller is adaptive and may be applied to any induction motor.