Emre Ozkop

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 Hybrid Photovoltaic PV Array-Battery Powered EV-PMDC Drive Scheme

In this study, a hybrid photovoltaic PV array-battery powered PMDC drive scheme is realized. The PID tri loop limited current loop controller with motor current of four-wheel drive electric vehicle is used. Photovoltaic array and DC motor model are obtained in the Simulink. The proposed system control mechanism is digitally simulated by using the MATLAB/ Simulink/Sim-Power Systems software. The dynamic performance of the system is brought into at the constant speed reference and the variable speed reference trajectory.

Performance of the Phaselet Frames-Based Digital Protection for Distributed Generation Units

This paper presents the development and performance evaluation of a digital protection for interconnected distributed generation units (DGUs). The developed protection detects and responds to transient disturbances (fault and nonfault conditions) based on the magnitudes and phases of the high-frequency sub-band contents, which are extracted from the d-q-axis components of the currents flowing through the point-of-common-coupling (PCC). These magnitudes and phases are extracted by six phaselet frames that are realized by a modulated filter bank that is composed of six digital high-pass filters (HPFs). The coefficients of HPFs are determined by biorthogonal phaselet basis functions. Extracted magnitudes and phases of the high-frequency sub-band contents of PCC d-q-axis current components provide signature information for accurate detection and identification of faults. The performance of phaselet frames-based digital protection is experimentally tested for two wind energy conversion systems (WECSs) and a photovoltaic (PV) system under different fault and nonfault conditions. Test results demonstrate reliable and timely responses, along with negligible sensitivity to the type and control of DGUs, type and location of faults, and loading levels.

A novel fuzzy logic tansigmoid controller for Wave Energy Converter-grid interface DC energy utilization farm

The paper presents a digital simulation and validation study of a novel control system for control of a Wave Energy Converter (WEC)-Battery renewable energy system for DC type loads. The performance and dynamic characteristics of the controllers to any load nonlinear J, B parameters and load torque is examined for PMDC Motor Drives. The proposed dynamic error driven control system is digitally simulated using the MATLAB/Simulink/SimPowerSystems software. The dynamic performance of the unified green energy Wave Energy-DC utilization system is examined for the proposed controller.

A fuzzy logic sliding mode controlled electronic differential for a direct wheel drive EV

In this study, a direct wheel drive electric vehicle based on an electronic differential system with a fuzzy logic sliding mode controller (FLSMC) is studied. The conventional sliding surface is modified using a fuzzy rule base to obtain fuzzy dynamic sliding surfaces by changing its slopes using the global error and its derivative in a fuzzy logic inference system. The controller is compared with proportional–integral–derivative (PID) and sliding mode controllers (SMCs), which are usually preferred to be used in industry. The proposed controller provides robustness and flexibility to direct wheel drive electric vehicles. The fuzzy logic sliding mode controller, electronic differential system and the overall electrical vehicle mechanism are modelled and digitally simulated by using the Matlab software. Simulation results show that the system with FLSMC has better efficiency and performance compared to those of PID and SMCs.

A novel active filter strategy for power mitigation and quality enhancements in a stand-alone WECS

In this study, a novel sinusoidal PWM Switched Power Filter (SPF) and Dynamic Voltage Compensation (DVC) scheme using VSC/SMC/B-B controller for power mitigation and quality enhancements in medium power distribution systems are simulated. The system is based upon a stand-alone Wind Energy Conversion Scheme (WECS) using an induction generator and the proposed system control mechanisms, which are digitally simulated by using the MATLAB/Simulink/SimPowerSystems software.

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.

Developing and testing phaselet frames-based digital protection for distributed generation units

This paper presents the development and performance testing of a new digital protection for interconnected distributed generation units (DGUs). The developed digital protection is structured to detect and respond to transient disturbances (fault and non-fault conditions) based on the magnitudes and phases of the high frequency sub-band contents extracted from the d-q axis components of the currents flowing through the point-of-common-coupling (PCC). These magnitudes and phases are extracted by employing a set of 6 phaselet frames. The employed phaselet frames are realized by a modulated filter bank that is composed of 6 digital high pass filters (HPFs). The coefficients of digital HPFs are determined by bi-orthogonal phaselet basis functions. Extracted magnitudes and phases of the high frequency sub-band contents of the PCC d-q axis current components provide signature information for accurate detection and identification of faults. The performance of phaselet frames-based digital protection is experimentally tested for two wind energy conversion systems and a photovoltaic system under different fault and non-fault conditions. Test results of the proposed digital protection demonstrate reliable and timely responses, along with negligible sensitivity to the type and control of DGUs, type and location of faults, and loading levels.

On the Experimental Performance of a Coordinated Antiislanding Protection for Systems With Multiple DGUs

This paper presents the implementation and performance evaluation of a coordinated antiislanding protection for systems with multiple distributed generation units (DGUs). The proposed coordinated antiislanding protection is structured to process the d - q-axis components of the instantaneous three phase apparent powers (sd and sq) determined at the point-of-common coupling for each DGU. The processing of sd and sq, for each DGU, is carried out by the wavelet packet transform (WPT) in order to extract their low-and high-frequency subband contents. The contents of WPT low-and high-frequency subbands offer signature information that can facilitate detecting the islanding condition and identifying the islanded DGU(s). The coordinated antiislanding protection is implemented in real time for experimental testing on a laboratory collector system that has three different DGUs. Experimental results reveal fast and accurate responses to islanding events, accurate identification of islanded DGUs, and negligible sensitivity to the type or ratings of protected DGUs. In addition, test results show that the d - q WPT-based coordinated antiislanding protection can accurately distinguish between islanding and nonislanding events, including faults, step changes in power delivery to the grid, unintentional loss of grid connection, low-voltage ride through, and sudden harmonic distortion on the grid side.

Voltage and energy utilization enhancement in a Stand-alone WECS Using a fuzzy logic controlled SPWM converter interface scheme

In this study, a novel sinusoidal PWM switched AC/DC/AC converter interface scheme using real novel tri-loop voltage error tracking fuzzy logic controller (FLC), to stabilize the stand alone Wind Energy Conversion Scheme (WECS) using an induction generator. The proposed novel sinusoidal Pulse Width Modulator (SPWM) switched (AC/DC/AC) converter (diode rectifier and 6-pulse IGBT inverter) interface scheme serves as a combined voltage stabilization regulator and maximum wind energy utilization and enhancement compensator.