Halil Ibrahim Okumus

Direct torque control of induction motor using space vector modulation (SVM-DTC)

In this study, direct torque control (DTC) of induction motor is evaluated based on space vector modulation (SVM). DTC is a method to control machine with utilizing torque and flux of motor controlled. The torque and current ripple are occurred in the conventional DTC. Reason of undesired torque and current ripple is low number of voltage vectors applied to the motor controlled by the conventional DTC technique. SVM-DTC is a technique to reduce the ripple. SVM techniques have several advantages that are offering better DC bus utilization, lower torque ripple, lower total harmonic distortion in the AC motor current, lower switching loss, and easier to implement in the digital systems. Simulation results from the classical and improved DTC are presented and compared. Result shows that the torque, flux linkage and stator current ripple are decreased with the improved DTC.

A fuzzy-logic controlled PV powered buck-boost DC-DC converter for Battery-Load system

In this paper, a fuzzy logic controlled buck-boost DC-DC converter powered by Photo Voltaic (PV) for Battery-Load system is presented. General design of the converter-load system is performed using Matlab/Simulink. In the FLC, different fuzzy membership functions are used and the results are compared with each other. The complete converter-load system has been developed, analyzed, and validated by the simulation. Performances have then been evaluated in detail for different operation conditions. The effects of the different fuzzy membership functions and the PV module parameters on the controller are also compared.

Fuzzy logic controlled buck-boost DC-DC converter for solar energy-battery system

In this paper, a Fuzzy Logic Controlled (FLC) buck-boost DC-DC converter for solar energy-battery systems is presented. General design of a fuzzy logic controller (FLC), based on Matlab/Simulink is performed. This design compared with Proportional Integrated (PI) controller. The complete control system has been developed, analyzed, and validated by simulation study. Performances have then been evaluated in detail for different study conditions.

Direct Torque Control of Induction Machine Drives Using Adaptive Hysteresis Band for Constant Switching Frequency

Hysteresis band control is one of the simplest and most popular techniques used in direct torque control (DTC) of induction machine drives. However the conventional fixed band hysteresis control has a variable switching frequency which causes serious problems in DTC. In this paper, the adaptive hysteresis band control strategy is proposed, where the hysteresis band is controlled in real time as variation of applied voltage vectors. Thereby reducing the torque ripple whilst maintaining a constant torque switching frequency. The proposed adaptive hysteresis band control technique is verified by simulations. The system is first simulated by MATLAB and tested by hardware in the loop. Then, it is implemented based on a TMS320C6711, 32-bit fixed point digital signal processor. Experimental results prove the feasibility of the proposed strategy as compared with the conventional method.

Fuzzy logic controlled parallel connected synchronous buck DC-DC converter for water electrolysis

Abstract In this paper, a Fuzzy Logic Controlled parallel connected synchronous buck DC-DC converter for water electrolysis system is presented. General design of a fuzzy logic controller, based on Matlab/Simulink is performed. This design can be compared with Proportional Integrated Proportional Derivative controller. The complete control system has been developed, analyzed and validated by simulation study. Performances have then been evaluated in detail for different study conditions. The stability of converter has been analyzed different nonlinear electrolyses loads.

Direct torque control for Linear Induction Motor

This paper presents a direct torque control for a Single-sided linear induction motor (SLIM). In the last years, in the field of research on linear induction drives, a lot of efforts have been oriented to improve the dynamics performances of these machines by using direct torque control. In order to insure a high transient behavior of the drive and to avoid the draw back of the parametric perturbations in the implemented control, the direct torque control is considered in this work.

Small signal analyses and hardware implementation of a buck-boost converter for renewable energy applications

In this study small signal analyses of a buck boost converter for a renewable energy applications is performed and hardware implementation is realized. State equations are solved for different study conditions and transfer function of uncontrolled system is obtained for stability analyses. Experimental hardware of buck boost converter realized with a MOSFET driver circuit which is designed for high frequency, high voltage and high current implementations. Experimental studies and results are given in the paper. The results show that hardware implementation of the system is accomplished.

Designing a load agent for power management with a multi-agent home automation system

In this study, a load agent design is performed for the power management which lets us use existing electrical energy for consumers needs, comfort and criteria in the areas such as flats and commercial buildings that independently meet their energy need from renewable energy sources. The load agent is designed on the basis of radio-frequency communication so it is a wireless communication system which also has the ability of switching off or making power flow by measuring current of the load. The agent has a flexible structure in order to be compatible with all ambient equipments. It can work with all equipments on the system properly, without any hardware changing. And this is shown in the paper.

Soft Set-Based Switching Faults Decision Making in DTC Induction Motor Drives

This paper introduces a method for detection and identification of IGBT-based drive open-circuit fault of DTC induction motor drives. The detection mechanism is based on soft set theory and wavelet decomposition, if it is detailed, ⊼-product decision making method and sym2 wavelet decomposition have been used in the detection mechanism. In this method, the stator currents have been used as an input to the system. The stator current has been used for the detection of the fault. The signal analysis has been performed up to the six level details wavelets decomposition. Faulty switch is detected by applying soft set theory to sixth level wavelets transformation. This is the first time applied to inverter in induction motor drives fault detection. The results demonstrate that the proposed fault detection and diagnosis system has very good capabilities.

A new torque controller for Direct Torque Controlled Induction Machine drives

Hysteresis band control is one of the simplest and most popular techniques used in direct torque control (DTC) of induction machine drives. However the conventional fixed band hysteresis control has a variable switching frequency which causes serious problems in DTC. To solve these problems a new constant switching frequency torque controller is proposed to replace the conventional hysteresis-based controller in this paper. The technique, based on the same concept, but with the hysteresis band implemented with fuzzy logic is proposed to optimize the DTC drive performance. The proposed technique is verified by simulations. The system is first simulated by MATLAB/Simulink and tested by hardware in the loop. Then, it is implemented based on a TMS320C6711, 32-bit fixed point digital signal processor. Experimental results prove the feasibility of the proposed strategy as compared with the conventional method.