Electronics Research Institute of Egypt

Cairo, Egypt

Electronics Research Institute of Egypt

Cairo, Egypt

Time filter

Source Type

Elsheakh D.M.,Electronics Research Institute of Egypt
Microwave and Optical Technology Letters | Year: 2017

This article describes three different types of broad multiband linearly and circularly polarized slot antennas (rectangular, circular, and triangular shaped slot) for millimeter wave wireless communication applications. Proposed antennas consist of a slot radiator on the top metal layer and coupled to a rectangular dielectric resonator above the slot. The conventional microstrip-line-feed is used for different shapes of slot antennas. An high frequency structure simulator, finite element method (FEM)-based, three-dimensional full wave electromagnetic solver simulator by ANSYS was used for the design of the proposed antennas. The final antennas were fabricated and their characteristics were measured. The bandwidth of |S11| <−10 dB was extended from 19.5 GHz up to 75 GHz. This band covers most of wireless MM-wave applications, fifth Generation mobile and wireless networks, and the WLAN, WPAN, and W-bands. The simulated and measured radiation efficiency, gain, and radiation pattern of the proposed antennas are presented. The average radiation efficiency and gain over the entire operating band are about 60% and 6 dBi, respectively. These antennas are also low profile and low cost. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:976–983, 2017. © 2017 Wiley Periodicals, Inc.


Elsayed T.A.,University of Heidelberg | Elsayed T.A.,Electronics Research Institute of Egypt | Fine B.V.,University of Heidelberg
Physical Review Letters | Year: 2013

We obtain a modified version of the Onsager regression relation for the expectation values of quantum-mechanical operators in pure quantum states of isolated many-body quantum systems. We use the insights gained from this relation to show that high-temperature time correlation functions in many-body quantum systems can be controllably computed without complete diagonalization of the Hamiltonians, using instead the direct integration of the Schrödinger equation for randomly sampled pure states. This method is also applicable to quantum quenches and other situations describable by time-dependent many-body Hamiltonians. The method implies exponential reduction of the computer memory requirement in comparison with the complete diagonalization. We illustrate the method by numerically computing infinite-temperature correlation functions for translationally invariant Heisenberg chains of up to 29 spins 1/2. Thereby, we also test the spin diffusion hypothesis and find it in a satisfactory agreement with the numerical results. Both the derivation of the modified regression relation and the justification of the computational method are based on the notion of quantum typicality. © 2013 American Physical Society.


Nafeh A.E.-S.A.,Electronics Research Institute of Egypt
International Journal of Green Energy | Year: 2011

In this paper, a new formulation for optimizing the design of a photovoltaic (PV)-wind hybrid energy home system, incorporating a storage battery, is developed. This formulation is carried out with the purpose of arriving at a selection of the system economical components that can reliably satisfy the load demand. Genetic algorithm (GA) optimization technique is utilized to satisfy two purposes. The first is to minimize the formulated objective function, which is the total cost of the proposed hybrid system. Whereas, the second is to ensure that the load is served according to certain reliability criteria, by maintaining the loss of power supply probability (LPSP) of the system lower than a certain predetermined value. Two computer programs are designed, using MATLAB code in a two M-files, to simulate the proposed hybrid system and to formulate the optimization problem by computing the coefficients of the objective function and the constraints. Also, these two programs are utilized together with the GA tool under MATLAB software to yield the optimum PV, wind, and battery ratings. The results verified that PV-wind hybrid systems feature lower system cost compared to the cases where either PV-alone or wind-alone systems are used. Copyright © Taylor & Francis Group, LLC.


Nafeh A.E.-S.A.,Electronics Research Institute of Egypt
International Journal of Green Energy | Year: 2010

This paper presents a novel maximum-power-point (MPP) tracking algorithm for photovoltaic (PV) energy conversion systems. The algorithm is based on utilizing the relation between the PV array MPP current and the solar insolation level at different atmospheric conditions. Also, a single-stage grid-connected PV system is proposed to track the MPP of the PV array, using the new algorithm, and to produce a sinusoidal output current in phase with the utility voltage (i.e., to obtain a unity power factor). The power stage of the proposed system includes, mainly, a direct current-alternate current inverter, whereas the control stage is based on utilizing both the Proportional Integral (PI) and the P resonant controllers. The obtained results satisfy the desired performance for the proposed system. Copyright © Taylor & Francis Group, LLC.


El-Sousy F.F.M.,Salman bin Abdulaziz University | El-Sousy F.F.M.,Electronics Research Institute of Egypt
IEEE Transactions on Industrial Informatics | Year: 2013

In this paper, an intelligent control system using recurrent wavelet-based Elman neural network (RWENN) for position control of permanent-magnet synchronous motor (PMSM) servo drive is proposed to achieve high precision tracking performance and to deal with the existence of uncertainties. The proposed intelligent optimal RWENN control system (IORWENNCS) incorporating an optimal controller, a RWENN controller and a robust controller. Based on the principle of optimal control, a position tracking controller is designed to minimize a quadratic performance index. In addition, a RWENN controller with accurate approximation capability is used to approximate a nonlinear function in the optimal control law. Moreover, a robust controller with adaptive bound estimation algorithm is proposed to confront the approximation error. The online adaptive control laws are derived based on the optimal control technique and Lyapunov stability analysis, so that the stability of the IORWENNCS can be guaranteed. Using the proposed control scheme, the position tracking performance is substantially improved and the robustness to uncertainties can be obtained as well. All control algorithms are implemented in a TMS320C31 DSP-based control computer. The simulation and experimental results confirm that the proposed IORWENNCS grants robust performance and precise tracking response regardless of load disturbances and PMSM uncertainties. © 2005-2012 IEEE.


El-Sousy F.F.M.,Salman bin Abdulaziz University | El-Sousy F.F.M.,Electronics Research Institute of Egypt
IEEE Transactions on Industrial Informatics | Year: 2013

In this paper, an adaptive dynamic sliding-mode control system (ADSMCS) with recurrent radial basis function network (RRBFN) for indirect field-orientation control induction motor (IM) drive is proposed. The ADSMCS comprises a dynamic sliding-mode controller (DSMC), an RRBFN uncertainty observer and a robust controller. The DSMC is proposed to reduce the chattering phenomenon. However, due to the uncertainty bound being unknown of the switching function for the DSMC, an ADSMCS is proposed to increase the robustness and improve the control performance of IM drive. In the ADSMCS, an RRBFN uncertainty observer is used to estimate an unknown nonlinear time-varying function of lumped parameter uncertainty online. Moreover, the adaptive learning algorithms for the RRBFN are derived using the Lyapunov stability theorem to train the parameters of the RRBFN online. Furthermore, a robust controller is proposed to confront the uncertainties including approximation error, optimal parameter vector and higher order term in Taylor series. A computer simulation and an experimental system are developed to validate the effectiveness of the proposed ADSMCS. All control algorithms are implemented in a TMS320C31 DSP-based control computer. The simulation and experimental results confirm that the ADSMCS grants robust performance and precise response regardless of load disturbances and IM uncertainties. © 2005-2012 IEEE.


Bayoumi E.H.E.,Electronics Research Institute of Egypt
WSEAS Transactions on Circuits and Systems | Year: 2013

To improve the overall dynamic performance of induction motor in direct torque control (DTC), a novel method of stator resistance estimation based on multi-resolution analysis wavelet PI controller is presented. This estimation method is anchored in an on-line stator resistance correction regarding the variation of the stator current estimation error. The main purpose is to adjust precisely the stator resistance value relatively to the evolution of the stator current estimation error gradient to avoid the drive instability and ensure the tracking of the actual value of the stator resistance. The multi-resolution wavelet controller process the error input with the gains depending on the level of decomposition employed. In order to limit the number of gains, this paper analyzes multi-resolution wavelet controller with a single gain constant. A separate fractional order integrator unit which enhances the controller performance with additional flexibility of tuning and also offers better steady state performance of the motor is introduced. The simulation results show that the proposed method can reduce the torque ripple and current ripple, superior to track the actual value of the stator resistance for different operating conditions.


Nafeh A.E.-S.A.,Electronics Research Institute of Egypt
International Journal of Numerical Modelling: Electronic Networks, Devices and Fields | Year: 2011

In this study, a stand-alone photovoltaic (PV)/battery-charging system is proposed to efficiently charge a lead-acid battery with the available maximum power from the PV array. The relative sizing of the battery characteristics with respect to the PV array characteristics is indicated. The maximum-power-point (MPP)-tracking operation is achieved through developing a new control loop, which is based on using the incremental conductance algorithm and the PI controller. The parameters of the PI controller are optimally tuned using the genetic algorithm (GA) by minimizing the integral of squared error and settling time. The proposed system was simulated twice by using MATLAB-SIMULINK and by writing the appropriate MATLAB code in an M-file. The SIMULINK model was designed to investigate the performance of the proposed system, whereas the M-file model was designed to be used with the GA tool under MATLAB software, to optimally tune the PI controller. The simulation results indicated a rapid tracking capability for the PV array MPPs and a good matching between the PV array and the battery under various charging conditions. © 2010 John Wiley & Sons, Ltd.


El-Fayez F.F.M.,Electronics Research Institute of Egypt | El-Fayez F.F.M.,King Saud University
IEEE Transactions on Industrial Electronics | Year: 2010

This paper proposes a hybrid H∞-based wavelet-neural- network (WNN) position tracking controller as a new robust motion-control system for permanent-magnet synchronous motor (PMSM) servo drives. The combinations of both WNN and H∞ controllers would insure the robustness and overcome the uncertainties of the servo drive. The new controller combines the merits of the H∞ control with robust performance and the WNN control (WNNC) which combines the capability of NNs for online learning ability and the capability of wavelet decomposition for identification ability. The online trained WNNC is utilized to predict the uncertain system dynamics to relax the requirement of uncertainty bound in the design of the H ∞ controller. The WNNC generates an adaptive control signal to attain robust performance regardless of parameter uncertainties (PU) and load disturbances. Systematic methodology for both controllers' design is provided. A computer simulation is developed to demonstrate the effectiveness of the proposed WNN-based H∞ controller. An experimental system is established to validate the effectiveness of the drive system. All control algorithms are implemented in a TMS320C31 DSP-based control computer. The simulated and experimental results confirm that the new motion controller grants robust performance and precise dynamic response regardless of load disturbances and PMSM PU. © 2006 IEEE.


Nafeh A.E.-S.A.,Electronics Research Institute of Egypt
International Journal of Energy Research | Year: 2011

In this paper a new charging algorithm is proposed to charge lead-acid batteries in photovoltaic (PV) systems. This algorithm can return discharged lead-acid batteries to their 100% state of charge (SOC) quickly and at the same time can avoid the associated problems of the excessive gassing phenomenon at overcharge. The proposed algorithm can be applied in the PV systems by using a DC-DC converter, which differs from the traditional on/off regulators in that it cannot only be used to charge the battery and protects it from overcharging, but it can also be used to quickly and safely charge the battery to 100% SOC through better exploitation of the available PV energy. The simulation results verify that, using the proposed algorithm, the discharged battery can always restore its 100% SOC compared with the conventional charging algorithms. © 2010 John Wiley & Sons, Ltd.

Loading Electronics Research Institute of Egypt collaborators
Loading Electronics Research Institute of Egypt collaborators