Dhafer Almakhles

• Doctor of Engineering
• CEO at Prince Sultan University

This study focuses on designing a controller for trajectory tracking of quadcopters using advanced sliding-mode techniques. Specifically, an integral terminal sliding-mode control based on an adaptive barrier function with a super-twisting reaching law is employed to achieve precise trajectory tracking. The performance of the controller is enhanced...

In conventional boost and quadratic boost converters, achieving the required output voltage necessitates a higher duty ratio. Additionally, these converters require switch and load diode ratings equal to the output voltage, which increases switching losses and reduces converter efficiency. This paper introduces an enhanced cubic boost converter (EC...

Loop closure detection, a critical component of Simultaneous Localization and Mapping (SLAM) systems, can be computationally intensive, particularly in swarm robotics where coordination among multiple agents is essential. Traditional SLAM methods often involve comparing each frame with all previous frames, leading to performance bottlenecks, especi...

The conventional quadratic boost converter (QBC) produces a high voltage gain. However, it has drawbacks, like switch voltage stress equal to the output voltage of the converter. This research introduced a novel approach: a scalable high-voltage gain converter strategically designed to address the voltage stress experienced by the switch and achiev...

Fuel cell-based electric vehicles (EVs) are gaining popularity in the automotive industry due to strict carbon emissions and fuel efficiency regulations. Fuel cells have inherently low voltage characteristics, making it challenging to interface with EV drive systems. This work proposes a unique topology implementing a non-isolated high step-up DC-D...

Disaster-altered environments present a unique challenge for Unmanned Ground Vehicles (UGVs), navigating dynamic environments for rescue operations. Existing loop closure detection methods already face significant challenges due to environmental variations, such as changing lighting conditions and the presence of moving objects. Disaster-stricken a...

We consider the problem of output feedback stabilization of LTI systems under event-triggering implementation. In particular, we assume that both the plant output and the control input are both transmitted over the network in an asynchronous manner. To that end, two independent event-triggering rules are constructed to generate the transmission ins...

Linear induction machines (LIMs) find widespread adoption in various applications, owing to their inherent advantages such as low noise, compact turning radius, and excellent climbing capability. LIMs are extensively utilized in linear metro applications. However, in practical operations, the output thrust shrinks with the increase in speed, which...

There is an increasing interest in achieving global climate change mitigation targets that target environmental protection. Therefore, electric vehicles (as linear metros) were developed to avoid greenhouse gas emissions, which negatively impact the climate. Hence, this paper proposes a finite set-model predictive-based current control (FS-MPCC) st...

This study focuses on stabilizing a bidirectional inductive wireless power transfer (WPT) system using an event‐triggered approach. It is only assumed the inductor currents on both the primary and pickup sides are measurable, and they are sent synchronously to the controller via a digital channel. To estimate the unmeasured states and maintain plan...

This paper, evaluate the effectiveness of a proposed speed loop pseudo derivative feedforward (PDFF) controller-based direct torque controller (DTC) for a PMSM drive against the performance of existing PI speed controller-based DTC and hysteresis current controller (HCC). The proposed PDFF-based speed regulator effectively reduces oscillation and o...

The utilization of switched inductors, involving parallel charging and series discharging of inductors, is extensively embraced in diverse DC–DC converters for attaining high voltage gain; nevertheless, the stress on switch voltage and diode current escalates considerably with an increased count of inductors integrated into the switched inductors n...

Power quality improvement is of paramount importance in both sin-gle as well as three-phase systems in the current scenario. Conventional control techniques used in three-phase systems do not apply to single-phase systems. Hence, we implement a Grid Connected Solar Inverter (GCSI) with Adaptive Quadrature Signal Generator (AQSG) based current contr...

This article proposes a novel seven-level boost active neutral point clamped topology with reduced component counts and a 3 v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in</sub> /(1-D) voltage gain. On the front side, a dual-input boost converter is used to reduce the stress on the dc-dc converte...

In a DC/AC microgrid system, the issues of DC bus voltage regulation and power sharing have been the subject of a significant amount of research. Integration of renewable energy into the grid involves multiple converters and these are vulnerable to perturbations caused by transient events. To enhance the flexibility and controllability of the grid...

This research endeavor demonstrates an improved differential evolution particle swarm optimization (IDEPSO) established photovoltaic (PV) maximum power point tracker (MPPT) for water pumping applications. A high gain boost- Ćuk converter has been utilized as an MPPT tracker, which provides better voltage regulation, high voltage gain, minimized st...

The sun is the primary energy source that provides our planet with the necessary energy for the continuation of life, and to harness this energy efficiently, photo-voltaic cells are used. The photovoltaic (PV) cells convert energy received from the sun into electric energy. The point of operation of the solar cell which provides maximum output powe...

Due to safety considerations and the challenges involved in tracking the maximum output of series-connected cells, solar photovoltaic (PV) arrays are generally operated at lower voltage levels. A multiport converter can be used to interface telecom DC loads, typically rated at 48 V and powered by PV arrays and battery energy storage systems. The gr...

Microgrids are seen as the future of reliable, sustainable and green energy source for myriad applications. The increasing dependence on microgrid also adds challenges on reliable management of power supply to vividly variant consumers, the major chunk being households coupled with an unprecedented rise in the demand for EV charging. This study aim...

Purpose This paper aims to present a cascaded pseudo derivative feedback (PDF) plus pseudo derivative feedback plus pseudo derivative feedforward (PDFF) controller for a permanent magnet synchronous motor (PMSM) to improve the transient response of the system. Design/methodology/approach Proportional integral (PI) plus PI controller and the propos...

The integration of communication channels with the feedback loop in a networked control system (NCS) is attractive for many applications. A major challenge in the NCS is to reduce transmissions over the network between the sensors, the controller, and the actuators to avoid network congestion. An efficient approach to achieving this goal is the eve...

The robust stabilization of doubly fed induction generators in wind turbines against external disturbances is considered in this study. It is assumed that the angular speeds of wind turbines can only be measured and sent to the controller in a discrete-time fashion over a network. To generate the sampling times, three different triggering schemes w...

Owing to the stochastic behavior of renewable energy activity and the multiple design considerations, the advancement of hybrid renewable energy-based microgrid (HREMG) systems has become a complex task. This study proposes a design optimization algorithm for the long-term operation of an autonomous HREMG along with the optimal system capacities. T...

Hybrid power systems based on renewable energy sources and diesel generators are efficient solutions for supplying electricity to remote and off-grid locations. One of the most crucial problems in hybrid power systems is frequency regulation, which is established by balancing the supplied power with the load demand using the load frequency control...

The stabilization of a permanent magnet synchronous motor using digital controllers requires the design of both the feedback law and an appropriate sampling frequency. Moreover, the design approach must be robust against existing uncertainties, such as disturbances and parameter variations. In this paper, we develop a stabilizing state feedback non...

In this article, problem of output tracking and disturbance rejection for Takagi-Sugeno fuzzy control systems with constant delay and external disturbances is discussed. Precisely, an enhanced equivalent-input-disturbance technique is incorporated into proportional-integral controller design to guarantee the output of the resulting system to tracks...

This article suggests a hybrid DC microgrid (HDCMG) with different levels of DC bus voltages to use for various types of loads. The available sources in the HDCMG are wind generating systems (WGSs), photovoltaic (PV) systems, battery banks, and the AC grid for emergencies. The various levels of the DC bus voltages are 760 V, 380 V, and 48 V for dif...

This article intends to provide an effective output tracking control protocol and enhanced disturbance rejection performance for a class of continuous-time Markov jump systems (MJSs) with time-varying delay and external disturbances. Precisely, enhanced EID strategy combined with a proportional integral control is proposed to solve the output track...

This research work addresses automatic generation control of multiple arenas and causes under various system disturbances. Sources within arena-1 comprises thermal, bio-diesel, in arena-2 sources represent thermal elements, in arena-3 sources are thermal and hydro units. An innovative endeavor has been undertaken to employ conglomerate controller w...

In this paper, we studied the feedback stabilization of an inductive power transfer system based on available output measurement. The proposed controller relies on a full-order state observer in order to estimate the unmeasured state. The control design problem is challenging due to the large dimension of the closed-loop system, which requires too...

The special design of linear induction motors (LIMs) leads to negative effects caused by the ending impact. This ending impact attracts attention towards the thrust control of linear induction motors because its value decreases sharply with speed. Therefore, this study proposes a finite state model predictive control with two voltage vectors based...

Multi‐input converters (MICs) play a significant role in the aspect of the integration of sources. The reliability of the converter can be enhanced by using a suitable fault tolerance converter design and control algorithm. A dual‐input single‐output (DISO) DC–DC converter with source fault tolerance is proposed in this paper. In the literature, th...

p>This article presents a single-dc-source seven-level (7L) inverter topology with a dynamic voltage gain. The two dcdc boost converters are connected in parallel for charging and in series for discharging to generate the seven-level output voltage at the load. The proposed topology's advantages are emphasized over existing boost inverters, demonst...

p>This article presents a single-dc-source seven-level (7L) inverter topology with a dynamic voltage gain. The two dcdc boost converters are connected in parallel for charging and in series for discharging to generate the seven-level output voltage at the load. The proposed topology's advantages are emphasized over existing boost inverters, demonst...

The special design of linear induction machines (LIMs) leads to adverse effects caused by the longitudinal and end effects. These effects make the thrust control of the LIMs most attractive because its value decreases sharply with the speed increase. Thus, finite-state model predictive control (FS-MPC) is developed to increase the performance of th...

p>We investigate the design of quantized event-triggered controllers for LTI systems with unknown initial states. The proposed approach is novel and incorporates interesting features. First, the quantizer that we synthesize is dynamic with exponential behaviour, which enables us to capture the state in a finite time. Second, once the state is captu...

p>We investigate the design of quantized event-triggered controllers for LTI systems with unknown initial states. The proposed approach is novel and incorporates interesting features. First, the quantizer that we synthesize is dynamic with exponential behaviour, which enables us to capture the state in a finite time. Second, once the state is captu...

p>This paper investigates the problem of asynchronous dynamic quantization for nonlinear systems with unknown initial conditions and subject to external disturbances and delays. We propose a novel two-level dynamic quantizer that only depends on the sign of the quantization error to quantize the actual input signal. Building on the sliding mode app...

p>This paper investigates the problem of asynchronous dynamic quantization for nonlinear systems with unknown initial conditions and subject to external disturbances and delays. We propose a novel two-level dynamic quantizer that only depends on the sign of the quantization error to quantize the actual input signal. Building on the sliding mode app...

This article comprehensively reviews recent Electric Vehicle (EV) charging infrastructure, technology, and issues related to charging station identification. A literature study on the above key areas shows an increasing consideration of EVs over the past decade. Further, the recommendations for user-friendly selection of the Charging Station (CS) a...

This article proposes two new high-frequency, thirteen-level switched capacitor inverter topologies. Compared with the counterpart existing topologies, which were recently published, the switch count, capacitor voltage, and voltage stress on the switch are reduced. In addition, the proposed topologies have inherited merits such as six-time voltage...

Power electronic converters are becoming more critical as renewable energy sources are linked to distributed generation systems. In this study, a "Two-Tier Converter" for high voltage gain with a low duty ratio, low voltage stress for the given voltage gain, continuous input current, and a grounded load arrangement have been made from two stages of...

Edge storage is driven by the emerging edge computing and application intelligence, which makes the data anonymization become essential to guarantee the security of the data. The risk with data anonymization is that it can be re-identified, where anonoymized data is matched with available information to discover the individual. Appropriate data ano...

This article presents a single-stage five-level boost inverter (5L-SBI) topology with reduced power components. The proposed topology falls under the self-balanced switch-capacitors (SCs) type and combines both a DC/DC boost converter and inverter with a switched-capacitor cell. The advantages of proposed topologies include the following: the numbe...

An enormous volume of data is generated in the Internet of Things (IoT), which needs to be anonymized before sharing with public or third parties to minimize reidentification risk and protect sensitive information. Data anonymization techniques can remove information capable of identifying individuals. However, inappropriate data anonymization can...

This paper proposes a modified primary flux linkage and an improved weighting less model predictive control for linear induction motors (LIMs) to enhance the drive system in terms of linear speed response, wide speed range, efficiency, and computation time. Sliding mode controller is presented in this work to get quick response instead of the use o...

This article describes the implementation of a proposed hybrid whale optimization algorithm differential evolution (WOADE) as a maximum power point tracking (MPPT) for wind energy conversion systems (WECS) employed for water pumping applications. The proposed hybrid MPPT algorithm provides rapid and zero oscillation power tracking to achieve the gl...

In this study, a new single-stage inverter with improved boosting performance was proposed to enhance the recently developed split-source inverter (SSI) topology. The study introduced new SSI configurations with high voltage gain. The proposed design features a voltage-lift cell made of capacitors, inductors, and diodes, which increases the boostin...

In this paper, a multistage MRAS speed estimator is formulated based on stator flux and electromagnetic torque quantities is proposed for reduced switch inverter (RSI) fed sensorless PMSM drive. The proposed configuration aims to eliminate speed sensor and reduce the switching losses, overall cost of the system. The proposed MRAS speed estimator is...

With the use of interleaved bidirectional dc-dc power converter (IBDPC) in dc shipboard microgrids (SMGs), the power can be delivered efficiently between the set of batteries and the dc bus during charging and discharging modes. The constant power loads (CPLs) dynamics of the propulsion motors control systems and hotel loads in dc SMGs is the prime...

This paper proposes a single-dc-source, seven-level (7L) inverter scheme with a dynamic voltage gain for solar applications. The proposed circuit is created by joining the two DC-DC boost converters in series for discharging and parallel for charging. The finite set model predictive controller is used to deliver the maximum power to the load. Addit...

We study the problem of output feedback control for nonlinear systems under event-triggered implementation and dynamic quantization. We focus on the case where the initial output measurement is unknown and we propose a novel dynamic quantization policy to capture the output in a finite time. Next, the event-triggering mechanism that we design relie...

This research article shows a new single dc source high boost seventeen-level (17L) switched-capacitor inverter topology with a continuous input current for photovoltaic applications. The proposed topology consists of two modules:-a front-end dc/dc converter that offers continuous input current and (ii) a switched capacitor module for high voltage...

The paper presents a five-level common ground type (5L-CGT) transformer-less inverter topology with double voltage boosting. The proposed inverter uses eight switches and two capacitors, charged at input voltage level. The inverter in its basic form acts as a string inverter for low-power PV applications. However, it can be extended to work as a sc...

In recent years, common ground (CG)‐type transformerless (TL) inverters have been paid more attention. However, the existing topologies have more voltage stress on either switch or on capacitor voltage or in both. This article proposes a novel five‐level TL inverter topology with a CG type and a voltage stress reduction on power components. The pro...

This paper proposes a novel non-isolated high voltage gain dc–dc converter with a boost2 (B2) technique. The derived single-switch hybrid voltage-lift topology generates a higher voltage conversion ratio with less component counts than traditional voltage-lift converters. Furthermore, to show its superiority, the proposed topology is compared with...

This article presents a novel quadruple boost inverter (QBI) with an integrated boost stage that comprises an inductor, a capacitor, a switch, and an input source. The inductor on the input side limits the inrush current and also the capacitor charging current ripples. The QBI topology comprises a dc source, an input inductor, nine switches, three...

The computational burden represents a challenge nowadays, especially with the advancement of new control techniques, such as model predictive control. Therefore, this paper presents an improved finite-state model predictive thrust control (FS-MPTC) for linear induction motor (LIM). The proposed FS-MPTC uses in the prediction stage half of the avail...

For microgrid operations, this article suggests a DC-DC Parallel Legs Linked High Gain Converter. To realize high voltage gain, the recommended converter is transformer-free and developed with n-parallel legs. One active switch, one capacitor, one inductor, and one diode make up each leg of the boost converter. The operating principle, characterist...

In recent times, important contributions and incorporation of renewable sources such as photovoltaic, fuel cells, etc., are the main reasons for the popularity of DC microgrids. Integrating renewable sources into the microgrid requires high-voltage, high-efficiency DC-to-DC converters. Without modification, traditional converters are not suitable t...