Papers by Prof. Dr. Saad Mekhilef
IEEE Access, 2021
Date of publication xxxx 00, 0000, date of current version xxxx 00, 0000.
Energy, 2019
In parallel to sustainable growth in solar fraction, continuous reductions in Photovoltaic (PV) m... more In parallel to sustainable growth in solar fraction, continuous reductions in Photovoltaic (PV) module and installation costs fuelled a profound adoption of residential Rooftop Mounted PV (RMPV) installations already reaching grid parity. RMPVs are promoted for economic, social, and environmental factors where they not only improve energy performance and reduce greenhouse effects but also contribute to bill savings. RMPV modules and energy conversion units are frequently subject to various types of anomalies which compromise power quality and promote fire risk and safety hazards for the personnel for which reliable protection is crucial. This article analyses historical data and presents a novel design that easily integrates with data storage units of RMPV systems to automatically process real-time data streams for reliable supervision. Dominant Transformed Components (TCs) are online extracted through multiblock Principal Component Analysis (PCA), most sensitive components are selected and their time-varying characteristics are recursively estimated in a moving window using smooth Kernel Density Estimation (KDE). Novel monitoring indices are developed as preventive alarms using Kullback-Leibler Divergence (KLD). This work exploits data records during 2015-2017 from thin-film, monocrystalline, and polycrystalline RMPV energy conversion systems. Fourteen test scenarios include array faults (line-to-line, line-to-ground, transient arc faults); DC-side mismatches (shadings, open circuits); grid-side anomalies (voltage sags, frequency variations); in addition to inverter anomalies and sensor faults.
TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES, 2019
This paper proposes a sensorless second-order switching surface to control a three-level boost co... more This paper proposes a sensorless second-order switching surface to control a three-level boost converter (TLBC). A predictive current method is proposed to reduce the number of sensors in the normal second-order switching surface method. Based on a developed model of the TLBC, the current is estimated and a switching surface is formulated in the state-energy plane. Simulation and hardware tests are carried out to verify the viability and the effectiveness of the proposed control technique. Results obtained show a good performance of the converter in term of DC-bus balancing and fast dynamic response under sudden load change.
International Journal of Microwave and Wireless Technologies, 2015
This paper presents a novel experimental simulation of ramp-time current control with fuzzy bandw... more This paper presents a novel experimental simulation of ramp-time current control with fuzzy bandwidth for wireless power transmission (WPT) systems. A fuzzy logic control algorithm was designed based on the structure of ramp-time current control in active power filters through simulation of ramp-time bandwidth variation to dynamically adjust the loop width of the ramp-time comparator. Ramp-time current control is the most suitable over other current control techniques and is thus selected for the experiment. Implementation of this approach prevents over-limit of switching frequency and enhances dynamic responses, resulting in long lifespan of power switches and smooth output for WPT systems. Finally, the hypothesis and simulation results were verified by analyzing the prototype model and experiment results.
2015 IEEE PELS Workshop on Emerging Technologies: Wireless Power (2015 WoW), 2015
Single switch inverter topologies have been proposed in many studies for WPT vehicle charging app... more Single switch inverter topologies have been proposed in many studies for WPT vehicle charging applications. This paper presents a systematic evaluation of Class Ф2 resonant inverter for WPT EV charging application. An analytical model of WPT vehicle charging system has been derived based on the common load network of Ф2 inverter. The Effects of system parameters, device stress and integration with WPT systems have been discussed to evaluate the inverter operation for power delivery up to 3 kW. Simulation results have been presented and experimental prototype has been discussed.
IEEE Access, 2022
Increasing the forecasting accuracy of photovoltaic (PV)-generated power is currently an importan... more Increasing the forecasting accuracy of photovoltaic (PV)-generated power is currently an important topic, particularly in the maintenance of the stability and reliability of modern electric grid systems. In this study, a model based on a particle swarm optimization (PSO)-optimized support vector regression (SVR) is proposed for the accurate forecasting of PV output power. In the process, an SVRbased model is established based on the most influential historical experimental data collected from an actual PV power station. A PSO-based algorithm is adapted for the selection of dominant SVR-based model parameters and improvement of performance. Moreover, a novel data preparation algorithm is developed for the preparation of a solar irradiance pattern on the basis of weather conditions and the percentages of cloud cover collected from online weather forecast reports. Finally, the proposed model is experimentally verified by deploying it to three different PV systems (1875Wp, 2000Wp and 2700Wp). Analytical and experimental results indicate that the proposed forecasting model ensures improved accuracy. The nRMSE of the proposed forecasting model is 2.841%. The proposed model will be effective in forecasting PV output power in existing PV systems. A guideline for the accurately forecasting of PV output power in practical applications is presented. INDEX TERMS Photovoltaic output power forecasting, particle swarm optimization, support vector regression, online weather report, optimized model.
Energies, May 26, 2023
An improved fractional-order sliding mode control (FOSMC) for PMSM is presented in this study to ... more An improved fractional-order sliding mode control (FOSMC) for PMSM is presented in this study to set the unavoidable parameters and to improve permanent magnet synchronous motors (PMSMs) drive performance, such as current and speed tracking accuracy. To determine the optimal parameters of the FOSMC for control speed in a PMSM drive, a neural network algorithm with reinforcement learning (RLNNA) is proposed. The FOSMC parameters are set by the ANN algorithm and then adapted through reinforcement learning to enhance the results. The proposed controller using RLNNA based on fractional-order sliding mode control (RLNNA-FOSMC) can drive the motor speed to achieve the referred value in a finite period of time, leading to faster convergence and improved tracking accuracy. For a fair comparison and evaluation, the proposed RLNNA-FOSMC is compared with conventional FOSMC by applying the integral of time multiplied absolute error as an objective function. The most commonly used objective functions in the literature were also compared, including the integral time multiplied square error, integral square error, and integral absolute error. To validate the performance of the RLNNA-FOSMC speed controller, different scenarios with different speeds steps were carried out. The computational results are promising and demonstrate the effectiveness of the proposed controller. Overall, the proposed RLNNA-FOSMC controller for the PMSM speed control system performed better than conventional FOSMC in numerical simulations.
Energies, Dec 14, 2017
A high computational burden is required in conventional model predictive control, as all of the v... more A high computational burden is required in conventional model predictive control, as all of the voltage vectors of a power inverter are used to predict the future behavior of the system. Apart from that, the common mode voltage (CMV) of a three-phase four-leg inverter utilizes up to half of the DC-link voltage due to the use of all of the available voltage vectors. Thus, this paper proposes a near state vector selection-based model predictive control (NSV-MPC) scheme to mitigate the CMV and reduce computational burden. In the proposed technique, only six active voltage vectors are used in the predictive model, and the vectors are selected based on the position of the future reference vector. In every sampling period, the position of the reference current is used to detect the voltage vectors surrounding the reference voltage vector. Besides the six active vectors, one of the zero vectors is also used. The proposed technique is compared with the conventional control scheme in terms of execution time, CMV variation, and load current ripple in both simulation and an experimental setup. The LabVIEW Field programmable gate array rapid prototyping controller is used to validate the proposed control scheme experimentally, and demonstrate that the CMV can be bounded within one-fourth of the DC-link voltage.
Sustainability, Apr 10, 2022
Research into modern transportation systems is currently in progress in order to fully replace th... more Research into modern transportation systems is currently in progress in order to fully replace the traditional inter-combustible engine with a noiseless, fast, energy-efficient, and environmentally friendly electric vehicle. Electric vehicles depend on an electric motor and require highly efficient converter drive circuits. Among these converters, DC-DC boost converters play a major role in charging not only the battery banks but also in providing the DC-link excitation voltage in transformerless applications. However, the development of these converters, which have higher voltage and current gain with minimum components, minimum voltage, and current stress, is quite challenging. Therefore, this research work aims to address these issues and also to improve overall system performance. These aims are achieved by developing a series LC-based single-stage boost converter, and extending its gain through a multi-stage boost converter using switch capacitor phenomena. This article also presents a complete operating model in continuous conduction mode. The proposed converter is tested under various testing conditions, such as output loading, input voltage levels, and duty cycle ratio for a 50 W resistive load. The results are compared with existing models. The proposed converter is stated to have achieved the highest efficiency, i.e., 96.5%, along with extendable voltage gain with reduced voltage and current stresses, which is a major contribution to this research field.
Sensors, Oct 9, 2019
The advancement of the Internet of Things (IoT) as a solution in diverse application domains has ... more The advancement of the Internet of Things (IoT) as a solution in diverse application domains has nurtured the expansion in the number of devices and data volume. Multiple platforms and protocols have been introduced and resulted in high device ubiquity and heterogeneity. However, currently available IoT architectures face challenges to accommodate the diversity in IoT devices or services operating under different operating systems and protocols. In this paper, we propose a new IoT architecture that utilizes the component-based design approach to create and define the loosely-coupled, standalone but interoperable service components for IoT systems. Furthermore, a data-driven feedback function is included as a key feature of the proposed architecture to enable a greater degree of system automation and to reduce the dependency on mankind for data analysis and decision-making. The proposed architecture aims to tackle device interoperability, system reusability and the lack of data-driven functionality issues. Using a real-world use case on a proof-of-concept prototype, we examined the viability and usability of the proposed architecture.
Energies, May 3, 2018
In a radial distribution network integrated with distributed generation (DG), frequency and volta... more In a radial distribution network integrated with distributed generation (DG), frequency and voltage instability could occur due to grid disconnection, which would result in an islanded network. This paper proposes an optimal load shedding scheme to balance the electricity demand and the generated power of DGs. The integration of the Firefly Algorithm and Particle Swarm Optimization (FAPSO) is proposed for the application of the planned load shedding and under frequency load shedding (UFLS) scheme. In planning mode, the hybrid optimization maximizes the amount of load remaining and improves the voltage profile of load buses within allowable limits. Moreover, the hybrid optimization can be used in UFLS scheme to identify the optimal combination of loads that need to be shed from a network in operation mode. In order to assess the capabilities of the hybrid optimization, the IEEE 33-bus radial distribution system and part of the Malaysian distribution network with different types of DGs were used. The response of the proposed optimization method in planning and operation were compared with other optimization techniques. The simulation results confirmed the effectiveness of the proposed hybrid optimization in planning mode and demonstrated that the proposed UFLS scheme is quick enough to restore the system frequency without overshooting in less execution time.
Frontiers in Energy Research
Sensors
There are three standard equivalent circuit models of solar cells in the literature—single-diode,... more There are three standard equivalent circuit models of solar cells in the literature—single-diode, double-diode, and triple-diode models. In this paper, first, a modified version of the single diode model, called the Improved Single Diode Model (ISDM), is presented. This modification is realized by adding resistance in series with the diode to enable better power loss dissipation representation. Second, the mathematical expression for the current–voltage relation of this circuit is derived in terms of Lambert’s W function and solved by using the special trans function theory. Third, a novel hybrid algorithm for solar cell parameters estimation is proposed. The proposed algorithm, called SA-MRFO, is used for the parameter estimation of the standard single diode and improved single diode models. The proposed model’s accuracy and the proposed algorithm’s efficiency are tested on a standard RTC France solar cell and SOLAREX module MSX 60. Furthermore, the experimental verification of the...
Now a days power system network operates at different states due to variation in load demand. As ... more Now a days power system network operates at different states due to variation in load demand. As a result, the power flow in transmission line keeps on changing which needs to be controlled precisely. Therefore, in this paper an attempt to control power flow in transmission line at various operating states of power system network using Unified power flow controller (UPFC) is considered. Fuzzy logic controller (FLC) has been employed to provide dynamic control of series and shunt converters of UPFC because it adapts wide range of dynamic changes of power sys-tem operations easily. The performance of the FLC based UPFC to control power flow under three operating states (nominal loading, variable loading and different referencing of power) of IEEE-14 bus system has been observed in PSCAD environment. The results show that FLC based UPFC is capable of controlling power flow in transmission line in whatever states the power system network is operating. In addition, to validate the statement that FLC based UPFC cope up with networks variation flexibly, the simulation results are compared with proportional integral (PI) based UPFC. The results show that the FLC based UPFC has better power flow capability compared to PI controller.
IEEJ Transactions on Electrical and Electronic Engineering, 2017
Minimizing power losses in a distribution system is commonly realized through optimal network rec... more Minimizing power losses in a distribution system is commonly realized through optimal network reconfiguration. In the past, network reconfiguration research was focused on planning, where the final configuration with the lowest power losses was the main goal. However, power losses during switching operations from the initial state to the final state of the configuration were not considered. This paper presents the optimal switching sequence path to minimize power losses during the network switching operation. Apart from this contribution, the simultaneous optimal network reconfiguration for variable load network and distributed generation (DG) output is also proposed. The proposed methodology involves the (i) optimal network reconfiguration with variable load and DG output simultaneously, and (ii) the optimal sequence of switching operations required to convert the network from the original configuration to the optimal configuration obtained from (i). The selected optimization technique in this work is the firefly algorithm. To assess the capabilities of the proposed method, simulations using MATLAB are carried out on IEEE 33-bus radial distribution networks. The results demonstrate the effectiveness of the proposed strategy to determine the sequence path of switching operations, as well as the optimal network configuration and optimal output of DG units.
IEEE Transactions on Industry Applications, 2021
Multilevel inverter (MLI) topologies play a crucial role in the dc-ac power conversion due to the... more Multilevel inverter (MLI) topologies play a crucial role in the dc-ac power conversion due to their high-quality performance and efficiency. This paper aims to propose a new switched-capacitor based boost multilevel inverter topology (SCMLI). The proposed topology consists of nine power semiconductor switches with one dc voltage source and two capacitors, capable of generating a nine-level output voltage waveform with twice voltage gain. With the addition of two switches, the proposed topology can be used for higher voltage gain applications. Other features of the proposed topology include self-voltage balancing of capacitors, parallel operation of capacitors, lower voltage stress across the switches, along with inherent polarity changing capability. To obtain the high-quality output waveform, selective harmonic elimination pulse width modulation (SHEPWM) technique is applied. In this technique, the detrimental low-order harmonics can easily be regulated and eliminated from the output voltage of MLI. The proposed topology is compared with the recently introduced SCMLI topologies considering various parameters to set the benchmark of the proposed topology. The performance of the proposed MLI is investigated through various experimental results using a laboratory prototype setup.
Sustainability, 2020
Recent advances in using renewable energy resources make them more accessible and prevalent in mi... more Recent advances in using renewable energy resources make them more accessible and prevalent in microgrids (MGs) and nano grids (NGs) applications. Accordingly, much attention has been paid during the past few years to design and operate MGs with high renewable energy sources (RESs) penetration. Energy storage (ES) is the crucial enabler for reliable MG operation to help MGs become more resistant to disruptions, particularly with the increased penetration of RESs. In this regard, this paper formulates a two-stage optimization framework to improve a grid-connected MG performance. Firstly, the optimal allocation decisions of the battery ES systems (BESSs) are provided to enhance the self-consumption rate of the RESs and the hosting capacity (HC) of the MG. Secondly, an operation strategy with the results (number, location, and capacity) of the BESSs obtained from the first stage is handled as an objective function to minimize the MG’s total operation cost. The IEEE 33-bus radial system...
Energies, 2018
A novel LC-LC2 compensated resonant converter topology with high efficiency and good controllable... more A novel LC-LC2 compensated resonant converter topology with high efficiency and good controllable voltage gain is presented in this paper. An additional receiving side inductor working together with the receiving coil has the contribution to work with a large range of air gap distance. Due to this property, proposed compensation technique is effective for IPT based EV charging application. Voltage gain with independent of load and input impedance having ZPA of the proposed resonant converter are observed by the frequency domain analysis. On the other hand, time domain analysis gives the circuit operation. A 500 W LC-LC2 compensated resonant converter prototype is built to testify the theoretical analysis. To observe the efficiency-comparison, an S-SP compensated resonant converter with a similar amount of output power under different air gap is also presented. In order to justify the effectiveness, the proposed compensation method is verified by the laboratory results. The highest e...
Energies, 2018
The rapidly increasing use of renewable energy resources in power generation systems in recent ye... more The rapidly increasing use of renewable energy resources in power generation systems in recent years has accentuated the need to find an optimum and efficient scheme for forecasting meteorological parameters, such as solar radiation, temperature, wind speed, and sun exposure. Integrating wind power prediction systems into electrical grids has witnessed a powerful economic impact, along with the supply and demand balance of the power generation scheme. Academic interest in formulating accurate forecasting models of the energy yields of solar energy systems has significantly increased around the world. This significant rise has contributed to the increase in the share of solar power, which is evident from the power grids set up in Germany (5 GW) and Bavaria. The Spanish government has also taken initiative measures to develop the use of renewable energy, by providing incentives for the accurate day-ahead forecasting. Forecasting solar power outputs aids the critical components of the energy market, such as the management, scheduling, and decision making related to the distribution of the generated power. In the current study, a mathematical forecasting model, optimized using differential evolution and the particle swarm optimization (DEPSO) technique utilized for the short-term photovoltaic (PV) power output forecasting of the PV system located at Deakin University (Victoria, Australia), is proposed. A hybrid self-energized datalogging system is utilized in this setup to monitor the PV data along with the local environmental parameters used in the proposed forecasting model. A comparison study is carried out evaluating the standard particle swarm optimization (PSO) and differential evolution (DE), with the proposed DEPSO under three different time horizons (1-h, 2-h, and 4-h). Results of the 1-h time horizon shows that the root mean square error (RMSE), mean relative error (MRE), mean absolute error (MAE), mean bias error (MBE), weekly mean error (WME), and variance of the prediction errors (VAR) of the DEPSO based forecasting is 4.4%, 3.1%, 0.03, -1.63, 0.16, and 0.01, respectively. Results demonstrate that the proposed DEPSO approach is more efficient and accurate compared with the PSO and DE.
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Papers by Prof. Dr. Saad Mekhilef