Nabil Ahmed

Prof. Nabil Ahmed

orcid

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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4 March 2022 in IEEE Access
Verified
Journal Article
Open access
NANabil Ahmed
Nabil Ahmed
BABader N. Alajmi
Bader N. Alajmi
IAIbrahim Abdelsalam
Ibrahim Abdelsalam
MMMostafa I. Marei
Mostafa I. Marei
In this paper, a soft switching interleaved boost converter (SS-IBC) using auxiliary resonant circuit for electric vehicles (EV) applications is proposed. Several phases of the proposed converter can be connected to make a multiphase interleaved boost converter. The operation of multiphase interleaved boost converter is identical to that of the one phase boost converter. All phases are ideally identical with shifted control signals and are controlled by PWM control strategy of equal switching frequency and duty cycle. The proposed converter can be considered as a cost effective retrofit to the grid integrated battery charging applications. It affords a steady electrical power for the load not only from the utility or classical energy storage systems as batteries, but also from renewable energy systems like photovoltaic (PV), wind or fuel cell systems. An appropriate design example demonstrates the size of the design circuit components and parameters are investigated. Analysis, design, and simulation of the presented converter are verified using PSIM simulation software on an 8.2 kW setup system with a conversion efficiency more than 97% over a wide output power conversion range from rated power to a minimum power of 460 W with complete soft switching operation. The converter performance is also validated experimentally on a downsized hardware rated 1.0 kW and the maximum efficiency is found to be 98.78%.


18 April 2022 in IEEE Access
Verified
Journal Article
Open access
BABader N. Alajmi
Bader N. Alajmi
MMMostafa I. Marei
Mostafa I. Marei
IAIbrahim Abdelsalam
Ibrahim Abdelsalam
NANabil Ahmed
Nabil Ahmed
This paper introduces an interleaved buck-boost converter with reduced power electronics devices count in comparison with the conventional topology. The proposed converter consists of a single buck converter followed by $n$ parallel interleaved boost converters. The buck switch is gated only if any of the boost switches is gated. In addition to the reduced switches count, the proposed converter offers the following advantages, soft start-up and shutdown capabilities. In addition, the buck stage gives the ability to protect the power electronic devices and to isolate the supply during load failure or overload. Moreover, the proposed converter performs as an interleaved boost converter for high voltage gain requirements with the same switching scheme. Furthermore, it offers fast dynamic performance with smooth transition from the buck mode to the boost mode. This paper investigates the eight different operating zones of the proposed three-phase interleaved buck-boost converter for non-overlapping gate signals operation. The detailed analysis and zones of operation are presented and experimentally validated. In addition, a simple control system is presented to operate the proposed converter as dc-dc converter or ac-dc converter. More study cases are carried out to evaluate the different capabilities of the proposed converter.

14 June 2022 in IEEE Open Journal of the Industrial Electronics Society
Verified
Journal Article
Open access
MMMostafa I. Marei
Mostafa I. Marei
BABader N. Alajmi
Bader N. Alajmi
IAIbrahim Abdelsalam
Ibrahim Abdelsalam
NANabil Ahmed
Nabil Ahmed
This paper introduces an integrated topology of isolated three-port dc-dc converter (TPC) to interface Photovoltaic (PV) and battery for standalone system. To guarantee zero circulating current flow between different ports while permitting bidirectional power flow at the battery port, auxiliary switches are utilized with the active bridges of the proposed TPC topology. In addition, a simple switching scheme based on Pulse Width Modulation (PWM) is proposed for the input ports of the TPC. This action eliminates the need for the phase shift modulation used for conventional isolated TPCs. While the PV port is controlled to track the maximum power point, the battery port is managed to regulate the load voltage. The paper presents the detailed mathematical analysis of the different operation modes of the proposed integrated TPC topology and the estimated control limits during charging and discharging of the battery. Consequently, dynamic limiters for the duty cycle of each port are set. The proposed integrated TPC based PV-battery system is simulated using PSCAD/EMTDC software package to validate the analysis of different operation modes and to assess the dynamic performance of the system. Moreover, experimental results are presented to authenticate different operation modes of the proposed TPC topology and to evaluate the dynamic behavior of the integrated PV-battery system.

11 December 2008 in Electric Power Components and Systems
Verified
Journal Article
Closed access
NANabil Ahmed
Nabil Ahmed
MMMasafumi Miyatake
Masafumi Miyatake
AAA. K. Al-Othman
A. K. Al-Othman
This article proposes a hybrid energy system combining solar photovoltaic and wind turbine as a small-scale alternative source of electrical energy where conventional generation is not practical. A simple and cost-effective control technique has been proposed for maximum power point tracking from the photovoltaic array and wind turbine under varying climatic conditions without measuring the irradiance of the photovoltaic or the wind speed. The proposed system is attractive because of its simplicity, ease of control, and low cost. A complete description of the proposed hybrid system, along with detailed simulation results that ascertain its feasibility, are given to demonstrate the availability of the proposed system in this article. Simulation of the hybrid system under investigation was carried out using PSIM software.

30 September 2020 in International Transactions on Electrical Energy Systems
Verified
Journal Article
Closed access
PDF file
NANabil Ahmed
Nabil Ahmed
SRSalahuddin Abdul Rahman
Salahuddin Abdul Rahman
BABader N. Alajmi
Bader N. Alajmi