In this paper, a design method of direct torque control (DTC) of an induction machine, which is based on fuzzy logic control (FLC), is proposed. The FLC which is introduced to improve the DTC uses a reduced number of fuzzy inference rules that facilitates the reduction of the FLC computation time. The improvement is performed by reducing the torque and stator flux ripples in the induction machine drive. Then, a hardware description that is based on the VHDL hardware description language of the proposed design is presented and discussed. The techniques of the parallel architecture, direct computation, and modular architecture are adopted for the design of the controller. Simulation and experimental results of the DTFC are compared with those of the conventional DTC. The comparison results illustrate the reduction in the torque and stator flux ripples of the DTFC. The validity of the proposed method is confirmed by the simulation and experimental results.

A robust direct torque control (DTC) strategy for an induction motor is proposed in this study. In fact, the proposed control strategy is defined by a combination of DTC, space vector modulation (SVM), input–output feedback linearisation (IOFL), a second‐order super‐twisting speed controller (STSC), and sliding‐mode‐load torque and stator‐flux observers with stator resistance estimation. First, non‐linear IOFL is suggested to achieve decoupled flux and torque control, and the SVM technique is utilised to control the inverter switching frequency which decreases the torque ripples and noise. Second, to improve the speed regulation, an STSC is added to an SVM‐DTC‐IOFL scheme. Furthermore, the sliding mode observers of the stator flux and of the load torque are proposed in order to improve the control performances by reducing uncertainties and to prevent the effects of the stator resistance variations. Indeed, this study presents the importance of implementing the suggested SVM‐DTC‐IOFL using a field‐programmable gate array (FPGA) circuit. The main interest of the FPGA implementation is the decrease in the control loop delay, due to the parallel processing offered by the FPGA. The performances of the proposed control algorithm are investigated by digital simulation using a Xilinx system generator tool and experimental implementation utilising FPGA‐Virtex‐5‐ML507.

This paper aims to improve the induction motor performances using a modified Direct Torque Control (DTC). The DTC is featured by its simple structure and fast dynamic response. Also, it does not require a speed sensor and it is less dependent on the motor parameters. However, the basic handicaps of this method are the torque ripples and the current distortions due to the presence of the hysteresis controllers. This paper aims; firstly, to replace the hysteresis controllers and the switching table by a fuzzy logic system in order to overcome these handicaps. Furthermore, the sampling frequency is another parameter which must be investigated to reduce the commutation losses and the harmonic stator current waves. The second purpose of this paper is to reduce the execution time using a Field Programmable Gate Array (FPGA). The FPGA is able to execute the Fuzzy DTC (FDTC) with a higher sampling frequency, thanks to its parallel processing relative to the Digital Signal Processor (DSP). The FDTC model is verified by simulation using system generator tool and validated by experimentation utilizing an FPGA Virtex 5. Thus, excellent performances at low processing time are obtained using the Xilinx FPGA Virtex 5.

Design and Implementation of Direct Torque Control Based on an Intelligent Technique of Induction Motor on FPGA Direct torque control;Fuzzy Logic Control (FLC);Induction motor;Real time;Xilinx system generator;FPGA.; In this paper the hardware implementation of the direct torque control based on the fuzzy logic technique of induction motor on the Field-Programmable Gate Array (FPGA) is presented. Due to its complexity, the fuzzy logic technique implemented on a digital system like the DSP (Digital Signal Processor) and microcontroller is characterized by a calculating delay. This delay is due to the processing speed which depends on the system complexity. The limitation of these solutions is inevitable. To solve this problem, an alternative digital solution is used, based on the FPGA, which is characterized by a fast processing speed, to take the advantage of the performances of the fuzzy logic technique in spite of its complex computation. The Conventional Direct Torque Control (CDTC) of the induction machine faces problems, like the high stator flux, electromagnetic torque ripples, and stator current distortions. To overcome the CDTC problems many methods are used such as the space vector modulation which is sensitive to the parameters variations of the machine, the increase in the switches inverter number which increases the cost of the inverter, and the artificial intelligence. In this paper an intelligent technique based on the fuzzy logic is used because it is allows controlling the systems without knowing the mathematical model. Also, we use a new method based on the Xilinx system generator for the hardware implementation of Direct Torque Fuzzy Control (DTFC) on the FPGA. The simulation results of the DTFC are compared to those of the CDTC. The comparison results illustrate the reduction in the torque and stator flux ripples of the DTFC and show the Xilinx Virtex V FPGA performances in terms of execution time.