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Author

Dhafer Almakhles

Bio: Dhafer Almakhles is an academic researcher from Prince Sultan University. The author has contributed to research in topics: Topology (electrical circuits) & Voltage. The author has an hindex of 12, co-authored 108 publications receiving 594 citations. Previous affiliations of Dhafer Almakhles include University of Auckland & University College of Engineering.

Papers published on a yearly basis

Papers
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Journal ArticleDOI
TL;DR: The state-of-the-art in unidirectional non-isolated DC-DC Multistage Power Converter (MPC) topologies for FC-VPT application is described and the suitability for different vehicular applications is stated.
Abstract: The automobile companies are focusing on recent technologies such as growing Hydrogen (H2) and Fuel Cell (FC) Vehicular Power Train (VPT) to improve the Tank-To-Wheel (TTW) efficiency. Benefits, the lower cost, ‘Eco’ friendly, zero-emission and high-power capacity, etc. In the power train of fuel cell vehicles, the DC-DC power converters play a vital role to boost the fuel cell stack voltage. Hence, satisfy the demand of the motor and transmission in the vehicles. Several DC-DC converter topologies have proposed for various vehicular applications like fuel cell, battery, and renewable energy fed hybrid vehicles etc. Most cases, the DC-DC power converters are viable and cost-effective solutions for FC-VPT with reduced size and increased efficiency. This article describes the state-of-the-art in unidirectional non-isolated DC-DC Multistage Power Converter (MPC) topologies for FC-VPT application. The paper presented the comprehensive review, comparison of different topologies and stated the suitability for different vehicular applications. This article also discusses the DC-DC MPC applications more specific to the power train of a small vehicle to large vehicles (bus, trucks etc.). Further, the advantages and disadvantages pointed out with the prominent features for converters. Finally, the classification of the DC-DC converters, its challenges, and applications for FC technology is presented in the review article as state-of-the-art in research.

99 citations

Journal ArticleDOI
TL;DR: This paper proposes a robust position control scheme for a quadrotor UAV system under uncertainties that combines integral sliding mode and backstepping sliding mode controllers in a double-loop control structure (i.e., inner-outer loop control).
Abstract: This paper proposes a robust position control scheme for a quadrotor UAV system under uncertainties. The proposed control algorithms combine integral sliding mode and backstepping sliding mode controllers in a double-loop control structure (i.e., inner-outer loop control). The design of the proposed controller is divided into two subcontrollers, namely, attitude and position controllers for the quadrotor. In this work, a nonsimplified six-degree-of-freedom quadrotor model is first established in the presence of disturbances. Afterward, we develop a robust backstepping sliding mode controller for the attitude control of the quadrotor. Next, a robust integral sliding mode controller is designed for the outer loop of the quadrotor to ensure the position trajectory tracking capability in the presence of disturbances. The stability and performance of the quadrotor is thoroughly investigated using Lyapunov stability analysis. Numerical simulations demonstrate the effectiveness of the developed solutions for a quadrotor.

67 citations

Journal ArticleDOI
TL;DR: A new cross-connected compact switched capacitor (C3SC) cell is introduced for multilevel inverter applications and all the switches of the proposed topology have a maximum blocking voltage within the input dc voltage.
Abstract: In this brief, a new cross-connected compact switched capacitor (C3SC) cell is introduced for multilevel inverter applications. The proposed CCS cell uses four switches and two diodes for interconnecting the input dc source and floating capacitors (FCs). A nine-level inverter is derived with the proposed C2SC cell requiring only ten switches and two FCs. The proposed C3SC cell-based MLI is self-balancing and has a voltage gain of two. All the switches of the proposed topology have a maximum blocking voltage within the input dc voltage ( v $_{in}$ ) value. The operating principle is detailed, and a simple logic gate based gate pulse generation scheme is presented. Detailed simulations and experimental results obtained from an 850 W prototype with several test cases are presented to validate the operation of the proposed topology. Finally, a detailed comparative assessment is performed with other recent SCMLIs to demonstrate the merits and superiority of the proposed topology.

54 citations

Journal ArticleDOI
TL;DR: A new multilevel inverter topology based on the switched-capacitor (SC) with a single source of dc voltage with seven-level single-source configuration is proposed, ideal for low voltage renewable energy applications.
Abstract: The new inverter topologies based on switched capacitor concept with voltage boosting ability are attractive for the low voltage applications. Such low voltage requirements allow a single-stage dc-ac power conversion, improving overall system performance, reliability and power density. This brief proposes a new multilevel inverter topology based on the switched-capacitor (SC) with a single source of dc voltage. The proposed topology is ideal for low voltage renewable energy applications. Seven-level (7L) output voltage is accomplished with triple voltage gain using two switched capacitors and 10 switches. Other major features of the proposed topology are self-voltage balancing of capacitor voltages, reduced number of switches with lower voltage stress and generation of negative voltage levels without using backend H-bridge. To show the advantages of the proposed topology, a detailed comparison with other similar topologies with seven-level single-source configuration has been accomplished in this brief. The proposed topology has been tested using the traditional level-shifted sinusoidal pulse width modulation (LS-PWM) technique. This brief includes various experimental results with different operating conditions to prove the performance of the proposed topology.

47 citations

Journal ArticleDOI
TL;DR: In this paper, the growth of the electric vehicle market year over year is very minimal due to insufficient EV charging stations, slow charging time, and insufficient charging infrastructure, and high charging time.
Abstract: Electric Vehicles (EV) offer eco-friendly transportation, but the growth of the electric vehicle market year over year is very minimal due to insufficient EV charging stations, slow charging time a...

44 citations


Cited by
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01 Jan 1992
TL;DR: In this paper, a multilevel commutation cell is introduced for high-voltage power conversion, which can be applied to either choppers or voltage-source inverters and generalized to any number of switches.
Abstract: The authors discuss high-voltage power conversion. Conventional series connection and three-level voltage source inverter techniques are reviewed and compared. A novel versatile multilevel commutation cell is introduced: it is shown that this topology is safer and more simple to control, and delivers purer output waveforms. The authors show how this technique can be applied to either choppers or voltage-source inverters and generalized to any number of switches.<>

1,202 citations

01 Jan 2016
TL;DR: In this paper, the authors describe how to download and install guidance and control of ocean vehicles in the house, workplace, or perhaps in your method can be all best place within net connections.
Abstract: By searching the title, publisher, or authors of guide you in reality want, you can discover them rapidly. In the house, workplace, or perhaps in your method can be all best place within net connections. If you objective to download and install the guidance and control of ocean vehicles, it is utterly easy then, past currently we extend the colleague to buy and make bargains to download and install guidance and control of ocean vehicles therefore simple!

611 citations

Journal Article
TL;DR: In this paper, the authors studied the problem of feedback stabilization over a signal-to-noise ratio (SNR) constrained channel and showed that for either state feedback, or for output feedback delay-free, minimum phase plants, there are limitations on the ability to stabilize an unstable plant over an SNR constrained channel.
Abstract: There has recently been significant interest in feedback stabilization problems over communication channels, including several with bit rate limited feedback. Motivated by considering one source of such bit rate limits, we study the problem of stabilization over a signal-to-noise ratio (SNR) constrained channel. We discuss both continuous and discrete time cases, and show that for either state feedback, or for output feedback delay-free, minimum phase plants, there are limitations on the ability to stabilize an unstable plant over an SNR constrained channel. These limitations in fact match precisely those that might have been inferred by considering the associated ideal Shannon capacity bit rate over the same channel.

379 citations

Journal ArticleDOI
TL;DR: This study analyzed various prospects of the country in renewable energy and discusses in-depth about the three Indian states, namely Karnataka, Gujarat, Tamil Nadu, which pioneers the renewable energy production in India.
Abstract: Clean and environment-friendly energy harvesting are of prime interest today as it is one of the key enablers in achieving the Sustainable Development Goals (SDGs) as well as accelerates social progress and enhances living standards. India, the second-most populous nation with a population of 1.353 billion, is one of the largest consumers of fossil fuels in the world which is responsible for global warming. An ever-increasing population is projected until 2050, and consequently, the energy demand in the upcoming decades will be co-accelerated by the rapid industrial growth. The Ministry of New and Renewable Energy (MNRE) with the support of National Institution for Transforming India (NITI) Aayog is working to achieve the Indian Government's target of attaining 175 GW through renewable energy resources. Many Indian states are currently increasing their renewable energy capacity in an objective to meet future energy demand. The review paper discusses in-depth about the three Indian states, namely Karnataka, Gujarat, Tamil Nadu, which pioneers the renewable energy production in India. The global energy scenario was discussed in detail with Indian contrast. Further, the barriers to the development of renewable energy generation and policies of the Indian government are discussed in detail to promote renewable energy generation throughout India as well as globally since the challenges are similar for other nations. This study analyzed various prospects of the country in renewable energy which has been done in a purpose to help the scholars, researchers, and policymakers of the nation, as it gives an insight into the present renewable energy scenario of the country.

254 citations

01 Jan 2006
TL;DR: In this article, a Takagi-Sugeno (T-S) model is employed to represent a networked control system (NCS) with different network-induced delays and a parity-equation approach and a fuzzy-observer-based approach for fault detection of an NCS were developed.
Abstract: A Takagi-Sugeno (T-S) model is employed to represent a networked control system (NCS) with different network-induced delays. Comparing with existing NCS modeling methods, this approach does not require the knowledge of exact values of network-induced delays. Instead, it addresses situations involving all possible network-induced delays. Moreover, this approach also handles data-packet loss. As an application of the T-S-based modeling method, a parity-equation approach and a fuzzy-observer-based approach for fault detection of an NCS were developed. An example of a two-link inverted pendulum is used to illustrate the utility and viability of the proposed approaches

209 citations