Journal of Electronics and Electrical Engineering

Robust Controller Design for a Grid-Connected VSI via an LCL Filter in the Presence of Unknown Grid Impedance

2024-11-13T15:38:17+08:00

Inverters connected to the grid can become unstable under specific grid impedance conditions. In order to find a solution to this problem, it is possible to ensure system stability and their robustness to R-L type grid impedances by satisfying two conditions. The first condition is to ensure that the closed-loop poles of the system are in stable positions to variations in the grid impedance. The second condition is reliant on the admittance model of the equivalent circuit. Specifically, the product of this admittance and the grid impedance must adhere to the Nyquist stability criterion. In this work, the stability of the converter connected to the grid through an LCL filter is analysed. For this purpose, the output admittance is modelled in the Laplace domain taking into account the behaviour of the discrete controller. In addition, to ensure that the closed-loop poles are in stable positions, the system open-loop response is analysed. These two conditions are examined across scenarios where system states are partially or completely fed back, for different system parameter values. Consequently, a robust controller is designed for variations of the R-L type grid impedance.

Design and Implementation of SCADA Architecture Based on MATLAB App Designer for a Hybrid Power System

2024-10-21T10:38:41+08:00

Hybrid renewable power systems (HRPS) are now considered reliable solutions for power generation under various conditions. A critical challenge for deploying HRPS involves the design and implementation of an effective supervisory control and data acquisition (SCADA) system, which is essential for real-time monitoring and control. The SCADA system plays a vital role in remote monitoring and control by enabling real-time data management, early fault detection, and timely troubleshooting. This study presents the design and implementation of a SCADA architecture based on a MATLAB App Designer for an HRPS consisting of wind turbines, photovoltaic panels, diesel generators, and batteries. The system utilizes Arduino Mega 2560 as remote terminal units (RTUs) to interface with actuators and measure critical system parameters such as voltage and current. Arduino boards can be controlled directly from MATLAB^® via the MATLAB^® Support Package for Arduino^® Hardware. A laptop is the main terminal unit (MTU), communicating with the Arduino via the Firmata protocol. MATLAB App Designer is the central monitoring interface, providing real-time data acquisition, processing, and visualization. In addition, a relay module is used to control the operation of the diesel generator. The relay module acts as an intermediary between the control system and the diesel generator, allowing for automated control of the generator's operation. It receives commands from the SCADA system to either start or stop the generator based on the energy demands and the availability of renewable resources. By managing the diesel generator's activity, the relay module helps ensure that the HRPS maintains a balanced and efficient power supply, minimizing reliance on non-renewable sources when renewable energy is sufficient. Based on experimental results, the proposed SCADA system effectively monitors and controls HRPS under different conditions.

Modeling and Simulation of Microgrid Dynamic Operation Modes Using MATLAB Simulink Software

2024-11-07T11:58:36+08:00

Microgrids are one of the effective solutions for utilizing renewable energy sources and distributed generations in distribution networks. This paper proposes a model to study operation modes of a microgrid consisting of a battery energy storage system (BESS), a solar power system, a diesel generator, a main grid and consumers. The microgrid components and control systems are modelled in the MATLAB Simulink software. Based on this model, different operating scenarios including the islanded mode and the black start mode are carried out to analyse and evaluate the dynamic response of the microgrid. The voltage, current, power, and frequency of the various locations on the system are simulated in the scenarios and they indicate that with the support of the BESS control, the microgrid is maintained at a stable operation condition in both studied modes.

Optimal Design of an Off-Grid Solar Energy System Integrated with a Diesel Generator for Urban Areas in Pakistan

2024-11-05T11:50:04+08:00

The growing energy demand in Pakistan, coupled with the challenges posed by reliance on imported fossil fuels, necessitates the exploration of alternative energy solutions. This study presents the design and techno-economic analysis of an off-grid hybrid energy system tailored for a residential neighborhood in Karachi, Pakistan. The system integrates individual solar energy solutions for seven housles, supplemented by a shared diesel generator to ensure a reliable power supply, particularly during load-shedding and grid outages. The study utilizes HOMER Pro software to model and optimize various configurations, taking into account local solar insolation levels and seasonal variability in energy demands. The optimized system includes photovoltaic (PV) panels, battery storage, and a shared diesel generator with individual connections and meters, with each house receiving a customized solution based on its specific energy requirements, ranging from 15 kWh/day to 45 kWh/day. The shared diesel generator is designed to reduce the need for large battery banks, thereby minimizing both capital and operational costs. The results demonstrate a cost-effective solution with a Levelized Cost of Energy (LCOE) of $0.2959/kWh and a Net Present Cost (NPC) of $15,562.55 over a 25-year period. This research highlights the potential for implementing such systems in urban areas of Pakistan, offering a sustainable, reliable, and economically viable alternative to conventional energy sources.

ZnO-Based Memristive Device for Temperature Sensing: Design, Modeling, and Performance Evaluation

2024-10-24T09:59:57+08:00

This paper presents the design and modeling of a highly sensitive ZnO-based memristive temperature sensor, underpinned by the fundamental physics of memristive behavior. Utilizing a multi-physics simulation tool, the proposed model accurately maps temperature variation contours within the ZnO pyroelectric material, paving the way for its application in temperature sensing. An in-depth exploration of the sensor's electrical properties under varying temperature conditions reveals exceptional sensitivity (8.9 µV/K) and showcases the inherent non-volatile memory switching behavior of the memristor, making it ideally suited for dynamic applications. Moreover, this sensor operates inherently bias-free, functioning as a self-powered solution for emerging fields like the Internet of Things.

Improving the ON/OFF Current Ratio and Ambipolarity of Doping-Less Tunneling Carbon-Nanotube FET Using Drain Engineering Technique

2024-10-18T12:03:36+08:00

This paper presents a novel structure utilizing a doping-less (DL) tunneling carbon nanotube field-effect transistor (T-CNTFET) with dual drain work functionality aimed at enhancing the ON/OFF current ratio. The proposed design features a zigzag carbon nanotube (CNT) of type (13, 0) with a diameter of 1 nm. It employs HfO2 as the gate oxide, which is 2 nm thick and has a dielectric constant of 16. The CNT serves as an intrinsic semiconductor for the source and drain regions, which are composed of metals with appropriate work functions. By selecting appropriate metals for the source and drain regions, the necessity for doping as a fabrication step is avoided, simplifying construction and reducing costs for the nanoscale device. This design includes two drain electrodes, each measuring 15 nm in length and having different work functions (DWFs). The work function of the drain positioned closest to the channel (DWFAC) is set at 3.9 eV, which is 0.5 eV lower than that of the CNT, while the other drain section has a work function of 3.4 eV, 1 eV lower than the CNT. The electrical properties of the device were examined through quantum numerical simulations using the non-equilibrium Green's function (NEGF) method. The results indicate that the proposed structure significantly decreases the OFF-state current and improves the ON/OFF current ratio. Additionally, the leakage current is substantially lowered, resulting in favorable changes to the device's ambipolarity, along with a reduction in hot carrier effects and subthreshold swing (SS).

Smart Building, Nuisance Electrical Failure, Remote Monitoring and Fault Recovery System

2024-09-05T11:34:34+08:00

Smart Buildings are the fastest growing buildings compared to conventional buildings and are expected to grow at a rate of 8.3% for the next decay. The global commercial building automation market was valued at US$32.96 billion in 2020 and is expected to reach US76.49 billion by the year 2031. The implementation of technological advancement, demand for energy-efficient construction, low operational cost, and occupant comfortability have helped Smart Building to grow. However, Smart Buildings are still facing issues, from various sensor network diversity, clear definitions of Smart Buildings, and continuous smartness during full or partial electrical internal fault occurrence. This indicates the building is smart as long as a continuous power supply is present. Thus, this research study investigated Smart Building's drawbacks and designed a circuit to be a solution to one of the drawbacks to rectify the issues. The design provides full monitoring for real and nuisance failures and enables the performance of fault recovery procedures remotely. The circuit interfaces with the safety Residual Current Devices (RCD) and the wireless smart Wi-Fi-controlled socket outlets. Food industries, hotels, and restaurants could be the beneficiaries of this circuit. This is due to cold stores and fridges, which can lead to significant production loss/reduction when failure time increases.

A Novel Static Model in d-q Coordinates for a Common-Emitter Amplifier

2024-09-02T10:40:45+08:00

This work presents a comprehensive investigation into a novel static model, formulated in d-q coordinates, for a common-emitter amplifier operating in a common-emitter configuration. The research starts with an in-depth study of the standard dc and ac models of the common-emitter amplifier, elucidating essential equations that capture its linear behavior. Moreover, the focus shifts towards a small-signal model, specially adapted to the ac operation of the common-emitter amplifier. Park's transformation is utilized to derive a static model in d-q coordinates, offering a thorough representation of the amplifier's behavior under steady-state conditions. Simulation techniques are employed to rigorously evaluate and compare the proposed d-q coordinate model with the standard model. The study demonstrates the static and fast response capabilities of the derived d-q coordinate model after system start-up, thus proving its viability and effectiveness. This research presents valuable contributions to the field of common-emitter amplifier modeling and analysis, offering insights that can advance the design and comprehension of amplification systems.

A Straightforward Method to Estimate Battery's Condition Based on Its Internal Resistance Value

2024-09-12T09:52:58+08:00

A battery condition monitor can be realized using several methods. Some of these methods have been proven to be more reliable than others. In this study, we focus on assessing a battery's condition based on its internal resistance value using a direct current method (DCM). We developed a simple, fast, and straightforward method, including the necessary equipment for this purpose. Only measurements of the battery's terminal (open-circuit) voltage and battery voltage under a certain load are required. We measured around 100 non-rechargeable AA batteries (double-A batteries) and estimated their internal resistances. Both alkaline and lithium-based batteries were tested. Our measurements show that measuring the terminal voltage (open-circuit voltage) alone does not provide an accurate enough status of a battery's condition or state-of-health, SoH. Especially when the battery condition is declining, the internal resistance value gives a better estimation of the battery's condition and usability.

A Comparative Analysis of Optimization Techniques for DSTATCOM in a 33 kV Radial Distribution System

2024-08-27T10:03:13+08:00

Utilization of Distribution Static Compensator (DSTATCOM) has proven to be instrumental in essential strategies aimed at mitigating power losses within electrical network systems. The growing demand for electricity and high maintenance costs have propelled DSTATCOM into a prominent position for discussion and consideration. This paper conducted a comprehensive comparative study employing optimization methods such as Differential Evolution (DE), Particle Swarm Optimization (PSO), and Artificial Bee Colony (ABC). The objectives of this study are to compare the performance in terms of Voltage Profile Improvement (VPI), Power Loss Reduction (PLR), and System Cost (SC) while selecting the best method as a suggestion for future research. The techniques were simulated in a MATLAB environment and a 50-bus system was used for real testing. The DE method emerged as the most effective technique in the analysis of the three objective functions. This outcome suggests that DE holds significant promise as a viable and efficient method for enhancing the performance of DSTATCOM in terms of VPI, PLR, and SC. These findings offer valuable guidance for future research endeavors in the realm of electrical network system optimization.

Sizing Optimization and Economic Modeling of a Stand-alone Hybrid Power System for Supplying RO System in McCallum

2024-08-12T09:24:24+08:00

Access to potable water has always been a fundamental human need. However, climate changes and water contamination are now exacerbating its scarcity. Consequently, the desalination of existing water sources has become increasingly critical. A reverse osmosis (RO) treatment system was employed in this study due to its lower energy consumption compared to other methods and its high effectiveness in removing lead from water. We aimed to provide electricity for a water system serving the remote community of McCallum in Newfoundland and Labrador. McCallum faces water shortages and lead contamination issues, and due to its isolated location, it remains disconnected from the electricity grid. To address this, we designed a hybrid energy system (HES) capable of supplying the necessary electricity for the water system. After conducting an economic analysis, we proposed the most optimal configuration using Homer Pro software. This configuration includes 3.19 kW PV panels, a 2-kW wind turbine, a 3-kW diesel generator, and 32.3 kWh batteries. The optimized system has a net present cost (NPC) of $44,382, which is 3.4 times less than that of the diesel-only system with an NPC of $153,940. Additionally, we investigated the system’s sensitivity to changes in diesel prices and the annual average load to observe its behavior. This paper offers a reliable and environment-friendly HES for the water system in McCallum.

A Novel ANFIS Controller for LFC in RES Integrated Three-Area Power System

2024-08-08T08:30:40+08:00

This paper presents a novel Adaptive Neuro-Fuzzy Inference System (ANFIS) model for Load Frequency Control (LFC) with an expanded input configuration, incorporating the integral of the area control error (ACE) alongside the traditional ACE and its derivative. This additional input captures historical ACE trends, enhancing the ANFIS control performance. The ANFIS training dataset, comprising ACE error, its derivative, and integral, is generated using a PID controller tuned by a variant of Particle Swarm Optimization (PSO) algorithm called an Adaptive Dynamic Inertia Weight Acceleration Coefficient (ADIWACO). Its evaluation on a three-area power system with renewable energy sources (RES) includes comparative analysis with PID, traditional 2-input ANFIS, Fuzzy Logic, and Artificial Neural Network (ANN) controllers. Simulation results demonstrate the superior performance of the proposed 3-input ANFIS controller in terms of performance metrics, consisting of overshoot, undershoot, settling time, steady-state error, and Integral Time Absolute Error (ITAE). Notably, the proposed ANFIS model shows a significant 75.89% improvement in ITAE value over the traditional 2-input ANFIS when communication delays and governor dead band constraints are considered, underscoring the significant impact of the additional input. System parameters variation of ±25%, further confirms the controller's robustness to uncertain model parameters. This study contributes to advancing real-world application of ANFIS controllers for LFC in interconnected power systems integrated with the two most widely developed renewable resources, namely solar and wind power plants.

Multi-Band Antennas for 4G, 5G FR1 and Wi-Fi 6E/7 Bands in Smartwatch Devices

2024-06-14T17:51:28+08:00

This article introduces an antenna design for smartwatch applications, with an overall size is 45 × 45 × 5.4 mm³. All antenna elements adopt the IFA (Inverted-F antennas) structures. The application bands include Global Positioning System (GPS), Wi-Fi 6E/7 with 2.4 GHz, 5.2 GHz, 5.8 GHz and 6 GHz bands, 4G LTE (Long Term Evolution) with B2 and B4, 5G n41, n77, n78, n79 bands, covering all Wi-Fi 6E/7 and the mainly bands of 5G FR1 bands. Additionally, this design also reserves a frequency band in the 6G mid-high band (6–9 GHz), ensures that design can be suitable for next generation of wireless systems. Furthermore, the antenna element designed for switching B2 and B4 bands to reduce the occupied space of the element. The design with five antennas and good performances can be applied to the bands of 4G, 5G FR1, and Wi-Fi 6E/7 systems in smartwatch applications.

Enhanced Harmonic Suppression for a Miniaturized Hairpin-Line Bandpass Filter with Meander Spurline

2024-02-28T12:22:40+08:00

The design of a fourth-order centrally corrugated double-folded hairpin line bandpass filter with a broad stopband and enhanced selectivity is demonstrated in this article. Initially, a double-folded hairpin-line bandpass filter (DFHLBF) is designed from a fourth-order conventional hairpin-line bandpass filter (CHLBF), which is centred at 2.5 GHz and has a fractional bandwidth of 3%. This results in a 68% size reduction. With this folding mechanism, the filter's skirt characteristic is only enhanced at the upper passband edge, resulting in an attenuation level of 40 dB at 2.65 GHz. The capacitive loading has then been incorporated by periodic rectangular corrugations that have disturbed the folded arms. Because of the high capacitive coupling between the folded arms, a symmetrical passband with an attenuation level better than 40 dB at both edges has been observed. Besides, a size reduction of 14% than that for the DFHLBF has been achieved. However, because of the imbalance of the modal phase velocities in the inhomogeneous microstrip filter construction, the stopband's attenuation level climbs to 8 dB. Rectangular meander spurlines have been added between the connected arms of the neighbouring centrally corrugated cells of the filters as a way to lower the attenuation levels of the harmonics. This creates a slow-wave effect between the odd- and even-modes of the propagating signals. This results in an overall size reduction of 81% over the standard hairpin-line filter and an enlarged stopband of up to 4.36f₀ with a rejection level of 42 dB.