ORCID Profile
0000-0002-8598-9983
Current Organisation
Minia University Faculty of Engineering
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Publisher: MDPI AG
Date: 28-02-2021
DOI: 10.3390/EN14051317
Abstract: The need for regulating the operation of unhealthy motor drives has motivated the researchers to modify the control techniques in order to be valid for the new drive state. The use of a fault-tolerant facility is an attractive feature of multiphase machines therefore, the applicability of different controllers has been established for the operation under open-phase fault conditions. The considered control algorithms were utilized to analyze the operation of the unhealthy system and evaluating the capability of the control to regulate the speed and torque under the fault condition. However, the majority of these studies considered only one control algorithm to be tested with the faulty system without comparing its performance with other techniques. The performance comparison is a vital way to visualize the features and characteristics of each algorithm. For this purpose, this paper deals with the performance comparison of the hysteresis controller, RFOC based on resonant controller and direct torque control (DTC) control under open-circuit fault conditions. A detailed comparison between the three control techniques is presented to outline the main differences between the three control procedures and identify the most appropriate technique in between.
Publisher: MDPI AG
Date: 18-04-2022
DOI: 10.3390/MATH10081348
Abstract: In this paper, an Artificial Neural Network (ANN) for accurate estimation of the speed and flux for induction motor (IM) drives has been presented for industrial applications such as electric vehicles (EVs). Two ANN estimators have been designed, one for the rotor speed estimation and the other for the stator and rotor flux estimation. The input training data has been collected based on the currents and voltage data, while the output training data of the speed and stator and rotor fluxes has been established based on the measured speed and flux estimator-based mathematical model of the IM. The designed ANN estimators can overcome the problem of the parameter’s variations and drift integration problems. Matlab/Simulink has been used to develop and test the ANN estimators. The results prove the ANN estimators’ effectiveness under various operation conditions.
Publisher: MDPI AG
Date: 19-02-2021
DOI: 10.3390/ELECTRONICS10040492
Abstract: The integration of wind energy systems (WECS) into the power grid through power electronic converters should ensure the high performance of the control system. In spite of several advantages of conventional Finite control set-model predictive controller (FCS-MPC), variable switching frequency and high computational burden are considered its main drawbacks. In this paper, a fast FCS-MPC of a machine side converter (MSC) of direct-driven permanent magnet synchronous generator (PMSG) based wind turbines for wind energy conversion system is proposed. The wind energy conversion system has been realized using a direct driven PMSG and a full-scale back-to-back power converter. The proposed controller is designed to reduce the required calculations in each horizon. In addition, the performance of conventional FCS-MPC is compared with the proposed method, and an improvement in total harmonic distortion spectra and simulation time required even when imposing a lower s ling frequency was found. To overcome the variable switching frequency problem, a modulation algorithm is introduced in the minimization process of modulated FCS-MPC. To keep the proposed system attached to the utility during a fault, a coordinated pitch angle control and low voltage-ride through (LVRT) algorithm is designed and inserted in the vector control of the grid side converter (GSC) to supply reactive power to the grid during fault for ensuring safe operation of the inverter and meeting the grid code requirements. The effectiveness of the proposed controller is illustrated using simulation results under different operating conditions.
Publisher: MDPI AG
Date: 29-10-2020
DOI: 10.3390/SU12218991
Abstract: The remarkable growth of distributed generation (DG) penetration inside electrical power systems turns the familiar passive distribution networks (PDNs) into active distribution networks (ADNs). Based on the backward/forward sweep method (BFS), a new power-flow algorithm was developed in this paper. The algorithm is flexible to handle the bidirectional flow of power that characterizes the modern ADNs. Models of the commonly used distribution network components were integrated with the developed algorithm to form a comprehensive tool. This tool is valid for modeling either balanced or unbalanced ADNs with an unlimited number of nodes or laterals. The integrated models involve modeling of distribution lines, losses inside distribution transformers, automatic voltage regulators (AVRs), DG units, shunt capacitor banks (SCBs) and different load models. To verify its validity, the presented algorithm was first applied to the unbalanced IEEE 37-node standard feeder in both passive and active states. Moreover, the algorithm was then applied to a balanced 22 kV real distribution network as a case study. The selected network is located in a remote area in the western desert of Upper Egypt, far away from the Egyptian unified national grid. Accordingly, the paper examines the current and future situation of the Egyptian electricity market. Comparison studies between the performance of the proposed ADNs and the classical PDNs are discussed. Simulation results are presented to demonstrate the effectiveness of the proposed ADNs in preserving the network assets, improving the system performance and minimizing the power losses.
Publisher: MDPI AG
Date: 03-04-2021
DOI: 10.3390/EN14071992
Abstract: Distribution transformer (DT) is a crucial component in power systems as it exchanges energies between different voltage levels or between utility grid and DC microgrids. Nevertheless, the operation of an oil-immersed DT is limited by the thermal and electrical capabilities of the internal insulating liquid. This paper aims to raise the efficiency of distribution transformers and preserve the environment by using a biodegradable insulating liquid instead of the conventional mineral insulating oil (MIO). This work examines the Egyptian case, where a real distribution network located in middle Egypt is selected as a pilot project. Study and analysis of the status que of the insulation system inside DTs are done with the aid of fault-tree analysis. The deficiency of the insulation system is confirmed by conducting an electronic survey of 100 expert participants. The most appropriate solution among three different alternatives is confirmed using the weighting and ranking method. The best choice suitable for the selected area is the substitution of MIO by synthetic ester (SE). The technical and environmental advantages achieved by the presented solution are discussed. The feasibility studies have proven that the solution is positively acceptable in all aspects. An execution plan is established for the application of proposed solution on the selected Egyptian distribution network.
No related grants have been discovered for Ahmed Diab.