Electrical Engineering & Electromechanics

Optimizing voltage control in AC microgrid systems with fuzzy logic strategies and performance assessment

2024-10-07T13:27:45+03:00

Introduction. Microgrids (MGs) have garnered significant attention for their numerous advantages, providing a solution for powering remote and distant locations while enhancing system reliability. In MGs, distributed generation inverters generally operate in parallel with the droop control strategies. This study focuses on the approach based on the P-f/Q-V droop control technique with virtual impedance for AC MG management. Essentially, the virtual impedance loop aims to decouple reactive and active power control without the need for additional physical components. Novelty. This research proposes enhancing voltage control in AC MG systems by introducing new methods of various control strategies, including PI and Fuzzy Logic Controller (FLC), and evaluating the effectiveness of each approach. The mathematical model of a system is always an approximation of real systems, variations or errors between mathematical models and real systems are referred to as uncertainty. This concept of uncertainty is present in both signals and models. In our study, uncertainties may involve factors related to the filter LC components. By employing advanced control strategies like FLC, the purpose of this research aims to contribute to the optimization and reliability of AC MG systems through the improvement of voltage control, which leads to guaranteed equitable power-sharing. Results. The major advantages of the FLC are robustness for any variation on the system and fast response. MATLAB software is used to simulate and validate the suggested control. Practical value. The simulation results show that the suggested control performs better in precise tracking optimization and robustness for all disturbances on the system compared to a PI controller. References 24, table 5, figures 11.

Comparative analysis between classical and third-order sliding mode controllers for maximum power extraction in wind turbine system

2025-04-20T21:21:01+03:00

Introduction. Maximizing power extraction in wind energy conversion systems is crucial for efficiency but remains a challenge due to rapid wind speed variations and the high inertia of the generator. Conventional controllers, such as the PI controller, struggle to maintain optimal performance under such dynamic conditions, leading to suboptimal power capture and increased system oscillations. The goal of this study is to enhance the efficiency of wind turbine systems by applying linear and nonlinear controllers in a maximum power point tracking (MPPT) strategy. This approach focuses on improving generator speed regulation and power conversion performance. Methods. A comparative analysis is conducted using three different control strategies: third-order sliding mode control (TO-SMC), classical sliding mode control (SMC) and PI control. These controllers are implemented in the generator speed loop of a wind turbine system, and their performance is evaluated through MATLAB/Simulink simulations. The assessment focuses on key performance metrics such as tracking accuracy, total harmonic distortion (THD), response time, and system stability. Results. The simulation results confirm that all controllers achieve MPPT, but with varying levels of effectiveness. The TO-SMC outperforms both SMC and PI controllers, offering higher efficiency, reduced chattering, better disturbance rejection, and lower THD (reduced from 73 % in SMC to 68.09 %). Additionally, TO-SMC significantly improves dynamic response, reducing overshoot and enhancing system stability. Originality. This study introduces a TO-SMC for MPPT in wind turbine systems, demonstrating its superiority over conventional control techniques. The findings highlight its ability to maintain optimal power extraction even under rapid wind variations, making it a promising solution for advanced wind energy systems. Practical value. By improving power quality, reducing system oscillations, and enhancing overall wind turbine efficiency, the proposed TO-SMC contributes to the reliable integration of wind energy into power grids. These advancements can benefit renewable energy operators, power system engineers, and researchers seeking efficient and robust MPPT solutions for wind turbines. References 13, figures 11.

Intelligent power control strategy based on self-tuning fuzzy MPPT for grid-connected hybrid system

2024-11-10T23:56:20+02:00

Introduction. This paper investigates various methods for controlling the Maximum Power Point Tracking (MPPT) algorithm within the framework of intelligent energy control for grid-connected Hybrid Renewable Energy Systems (HRESs). The purpose of the study is to improve the efficiency and reliability of the power supply in the face of unpredictable weather conditions and diverse energy sources. Intelligent control techniques are used to optimize the extraction of energy from available sources and effectively regulate energy distribution throughout the system. Novelty study is employing intelligent control strategies for both energy optimization and control. This research distinguishes itself from conventional approaches, particularly through the application of Self-Tuning Fuzzy Logic Control (ST-FLC) and fuzzy tracking. Unlike conventional methods that rely on logical switches, this intelligent strategy utilizes fuzzy rules adapted to different operating modes for more sophisticated energy control. The proposed control strategy minimizes static errors and ripples in the direct current bus and challenges in meeting load demands. Methods of this research includes a comprehensive analysis of several optimization techniques under varying weather scenarios. The proposed strategy generates three control signals that correspond to selected energy sources based on solar irradiation, wind velocity and battery charging status. Practical value. ST-FLC technique outperforms both conventional methods and standard Fuzzy Logic Controllers (FLCs). It consistently delivers superior performance during set point and load disturbance phases. The simulation, conducted using MATLAB/Simulink. The results indicate that fuzzy proposed solution enables the system to adapt effectively to various operational scenarios, displaying the practical applicability of the proposed strategies. This study presents a thorough evaluation of intelligent control methods for MPPT in HRESs, emphasizing their potential to optimize energy supply under varying conditions. References 27, tables 6, figures 18.

Electric drive vehicle based on sliding mode control technique using a 21-level asymmetrical inverter under different operating conditions

2025-01-16T12:01:52+02:00

Introduction. Electric vehicles (EVs) have drawn increased attention as a possible remedy for the energy crisis and environmental issues. These days, EVs can be propelled by an extensive range of power electronics to produce the energy required for the motor and operate efficiently at high voltage levels. Multilevel inverters (MLIs) were designed to address the challenges and limitations of traditional converters .The novelty of the research that is being presented a 21-asymmetric MLI with reduced switching using pulse width modulation technique for powering electric propulsion system of EVs, with the proposed topology delivering notable enhancements in both performance and cost-efficiency compared to conventional asymmetric designs. Purpose. Improving EV performance by utilizing sliding mode control (SMC) technique for controlling a permanent magnet synchronous motor (PMSM) powered by a 21-level reduced switching inverter topology. Methods. This study focuses on assessing the feasibility of a 21-asymmetric MLI with reduced switching. This inverter utilize different input voltage levels for various components and modules, enabling the combination and subtraction of these voltages to create multiple voltage levels for use in the traction system of electric vehicles, designed to power a PMSM. The motor’s operation is controlled using SMC technique with three distinct surfaces, with consideration for the vehicle’s dynamic behavior. Results. Proved that, using a 21-asymmetric MLI to optimize the quality of the output voltage for improving the performance of the EV. The proposed topology offers a cost-effective and simple system that is easy to maintain. Practical value. To assess the effectiveness and resilience of the suggested control system, we conducted simulations using MATLAB/Simulink. Notably, the target speed adheres to the urban driving schedule in Europe, specifically the ECE-15 cycle. References 21, tables 2, figures 10.

Improvement teaching-learning-based optimization algorithm for solar cell parameter extraction in photovoltaic systems

2024-10-22T10:37:36+03:00

Introduction. This study investigates parameter extraction methods for solar cell analytical models, which are crucial for accurate photovoltaic (PV) system design and performance. Problem. Traditional single-diode models, while widely used, often lack precision, leading to inefficiencies in parameter extraction essential for reliable PV systems. Goal. The work aims to improve the Teaching-Learning-Based Optimization (TLBO) algorithm to enhance the accuracy of parameter extraction in PV models. Methodology. We adopt an enhanced single-diode model, integrating modifications into the TLBO algorithm, including dynamic teaching factor adjustment, refined partner selection, and targeted local searches with the fmincon function. Comparative analysis with experimental data from four PV systems validates the model’s accuracy. Results. The enhanced TLBO algorithm achieves superior convergence and reliability in parameter extraction, as evidenced by 500 independent runs. Originality. Key contributions include methodological improvements such as dynamic adjustment of the teaching factor and a new approach to partner selection, which significantly optimizes the algorithm’s performance. Practical value. This research provides a robust framework for solar cell parameter extraction, offering practical benefits for PV system designers and researchers in improving model accuracy and efficiency. References 35, table 1, figures 15.

Adaptive finite-time synergetic control for flexible-joint robot manipulator with disturbance inputs

2025-02-25T22:41:28+02:00

Introduction. In this paper, the adaptive finite time controller is designed for flexible-joint manipulator (FJM) to stabilize oscillations and track the desired trajectory based on synergetic control theory (SCT) under disturbance inputs. The problem of the proposed work consists in the development of a mathematical model of the flexible joint while ignoring the nonlinear components of the actuator and synthesizing the control law that ensures the system stability within a settling time. The aim of this study is to use finite-time synergetic controller to ensure the reduction of system tracking error, avoid vibration and achieve steady state in a certain time period. An adaptive synergetic law is developed to solve the problem of uncertainty in the mathematical model of the actuator of FJM and input disturbances. Methodology. First, based on SCT the finite-time controller is constructed via the functional equation of the first manifold. The control law is designed to ensure the movement of the closed-loop system from an arbitrary initial state into the vicinity of the desired attractive invariant manifold, that is, the target attracting manifold. Secondly, to adjust the control law online, an adaptive law is developed to estimate the disturbance acting on the input. Then, the Lyapunov function is used to prove that the system can be stabilized in a sufficiently small neighborhood of the origin within finite time under input disturbances. Novelty. The implemented controller is effective in ensuring stability over a given time, minimizing the jitter problem while maintaining tracking accuracy and system robustness in the presence of input noise. Results. Numerical simulation and experimental results are presented to illustrate the effectiveness of the proposed method. The research directions of the model were determined for the subsequent implementation of the results in experimental samples. References 25, table 1, figures 7.

The effect of SiO2 microparticle concentration on the electrical and thermal properties of silicone rubber for electrical insulation applications

2024-10-09T20:56:29+03:00

Introduction. Polymeric insulators, first developed in the 1950s, have since seen substantial advancements in both design and manufacturing, making them increasingly appealing to users and manufacturers in the electrical industry. Extensive testing in both laboratory and outdoor environments has consistently demonstrated that polymeric insulators outperform traditional porcelain and glass counterparts. Among the various polymeric materials, silicone rubber (SiR) has emerged as one of the most promising candidates for high-voltage insulators. Its superiority is attributed to a unique combination of properties, including a non-conductive chemical structure, high dielectric strength, and excellent resistance to scaling. To further enhance these properties, SiR is often combined with fillers to form composite materials. These SiR composites are at the forefront of advanced high-voltage insulation systems, offering improved mechanical, thermal, and electrical performance. As a result, they not only meet the rigorous demands of high-voltage applications but also provide a significantly extended service life. Goal. This study aims to enhance the dielectric and thermal properties of SiR by incorporating micron-sized silicon dioxide (SiO₂) filler. Methodology. SiR-based composite samples were prepared by incorporating micron-sized SiO₂ at weight fractions of 10 %, 20 %, 30 %, and 40 % of the total composition. Initially, the samples were heated to specific temperatures (25°C, 60°C, 80°C, and 100°C) before undergoing dielectric strength testing to evaluate their performance under varying thermal conditions. Additionally, the samples were subjected to thermal aging for durations of 10, 20, and 30 minutes at the same temperatures before dielectric strength assessment. The results indicated that increasing the filler concentration enhanced the dielectric strength of the SiR/SiO₂ composites. The highest breakdown voltage was observed at a filler concentration of 30 %. Practical value. Incorporating micron-sized SiO₂ filler into the SiR matrix enhanced the composite's resistance to thermal stress. Compared to SiR-based composites with varying SiO₂ concentrations, pure SiR exhibited the lowest dielectric strength. References 48, tables 5, figures 8.

Efficiency of neutralization of electric charges on the surface of dielectric nonwoven fabric of two dual and triode electrode systems

2024-12-01T21:52:18+02:00

Introduction. The accumulation of electrostatic charges are exploited in various technological and industrial applications, but they can also pose significant challenges, especially due to the accumulation in inappropriate locations that can reach dangerous levels. Problem. The static charges are often considered annoying and constitute one of the main sources of hazards. Thus, their neutralization is more than necessary. The objective of this work is to improve the neutralization rate with equipment that can be easily integrated in the production lines. Novelty. The paper reports a comparative study of the neutralization efficiency of two electrode systems, dual and triode, with different high alternating voltages at the industrial frequency of 50 Hz. The use of the industrial frequency of 50 Hz reduces the elements of the neutralization equipment. By connecting the grid to ground, we aim to impose a zero potential on the surface of the initially charged polypropylene fibrous dielectric and to determine the variation of the neutralization rate as a function of the discharge intensity (voltage amplitude). Methodology. The samples were charged during 10 s using a triode-type corona electrode configuration supplied by negative or positive DC high voltage. After 300 s of the charging process. The neutralization was performed during 4 s, using the dual or the triode systems powered by sinusoidal high voltage. Neutralization efficiency is achieved by non-contact sampling of surface potential profiles before and after neutralization. The results show that neutralization efficiency is proportionate to the discharge current intensity. The neutralization using the triode system is more efficient. The results show the possibility of imposing a desired potential on the charged or uncharged dielectric surface by acting on the potential of the metallic grid and the discharge intensity of the triode system. Practical value. The results demonstrate the proportionality of the neutralization efficiency with the discharge intensity for the triode system. Therefore, an adjustment of the voltage amplitude is necessary in order to optimize its efficiency for the dual system. References 30, figures 7.

Design and control of a DC-DC buck converter using discrete Takagi-Sugeno fuzzy models

2024-09-10T13:38:42+03:00

Introduction. A DC-DC buck converter plays a crucial role in industrial applications by efficiently stepping down voltage levels to power various electronic components and systems. However, controlling a buck converter is challenging due to its inherently nonlinear behavior. This paper presents a novel fuzzy tracking control approach for the buck converter, based on the combination of time-discrete Takagi-Sugeno (T-S) fuzzy models and the concept of virtual desired variables (VDVs). Originality. This paper introduces an innovative fuzzy tracking control that integrates time-discrete T-S models and VDVs concept to develop an efficient digital controller. Goal. The proposed fuzzy control strategy aims to regulate the output voltage regardless of sudden change in setpoint, load variation and change in input voltage. Methodology. The proposed control strategy aims to regulate the output voltage of a DC-DC buck converter. The design starts with a discrete T-S fuzzy controller based on the nonlinear model of the buck converter. A nonlinear tracking controller is developed using a virtual reference model that incorporates the VDVs concept. System stability is analyzed via Lyapunov’s method and expressed through linear matrix inequalities. Results. Simulation tests under varying conditions validate the accuracy and effectiveness of the controller in achieving superior voltage tracking performance. Comparative analysis with a conventional PID controller highlights faster dynamic response and better tracking, showcasing the advantages of the proposed approach. Practical value. The practical value of this research lies in the development of a robust voltage control strategy for DC-DC buck converters and the establishment of reliable and efficient electrical systems using discrete-time fuzzy T-S control. This work also opens up the prospect for future implementation in experimental prototypes. References 30, table 2, figures 7.

Single-phase power shunt active filter design using photovoltaic as reactive power compensator

2024-09-24T20:09:25+03:00

Introduction. The rapid production of electronic equipment circulating and used by the public has resulted in a decline in the power quality in the power system. The goal of the article is to build a parallel active filter for reactive power compensation in a single-phase power system using photovoltaic (PV) as the input DC link voltage for the inverter through simulation modeling using MATLAB/Simulink. Methods. The method used is to design a parallel active filter modeling for a single-phase electrical network that serves loads in the form of AC DC converters with inductive recessive and capacitive recessive loads using MATLAB/Simulink. Results. The simulation results show that the total harmonic distortion (THD) value of the system before being screened is 37.93 % for inductive resistive loads and 18.77 % for capacitive resistive loads, and after going through screening the THD value can drop significantly by 0.35 % for inductive resistive loads and 1.45 % for resistive capacitive loads. Practical value. PV systems can be used as power generators to provide a voltage of 800 V on a single-phase parallel active power filter using a voltage source inverter. References 30, table 2, figures 11.

Simplified method for analytically determining the external magnetostatic field of uncertain extended technical objects based on near-field measurements

2025-04-20T21:34:54+03:00

Introduction. An important scientific and technical problem of magnetism of uncertain extended energy-saturated objects - such as naval vessels and submarines is implementation of strict requirements for magnetic silence based on mathematical modeling of magnetic field, adequate to its real measurements. The purpose of the work is to develop a simplified analytical method for determining the external magnetostatic field of extended technical objects with uncertain magnetic field sources based on near-field measurement data using spherical and spheroidal sources in a Cartesian coordinate system. Methodology. Forward problems of magnetostatics solved based on developed method of analytical calculation of magnetostatic field induction of spherical and spheroidal sources in Cartesian coordinate system based on near-field measurements. Geometric inverse problems of magnetostatics for solving prediction and control problems of magnetic silence of technical object calculated based on vector games solution. Both vector games payoff calculated as forward problems solutions Wolfram Mathematica software package used. Results. The results of prediction of magnetic field magnitude in far zone of extended technical objects based on designed multispheroidal magnetic field model in form of spatial elongated spheroidal harmonics in prolate spheroidal coordinate system and in form of multispherical magnetic field model in form of spatial spherical harmonics in spherical coordinate system using measurements near field and taking into account magnetic characteristics uncertainty of extracted technical objects. Originality. For the first time, a method of simplifying the mathematical modeling of the magnetic field of an uncertain long energy- saturated object developed based on development and application of method of analytical calculation of induction of magnetostatic fields of spherical and spheroidal sources in the Cartesian coordinate system. Unlike known methods developed method allows modeling magnetic field directly in Cartesian coordinate system based on near-field measurements without finding magnetic induction projection in prolate spheroidal coordinate system and in spherical coordinate system without their translation from prolate spheroidal coordinate system and in spherical coordinate system in Cartesian coordinate system and vice versa. Practical value. The possibility of a more than 10 times calculation time reduction of magnetic field induction of magnetic field elongated spheroidal sources and the possibility of a more than 4 times calculation time reduction of magnetic field induction of magnetic field spherical sources when magnetic field calculating of uncertain extended energy-saturated object based on development and application of analytical calculation method of magnetostatic field induction of spherical and spheroidal sources in the Cartesian coordinate system based on near-field measurements shown. References 50, tables 2, figures 4.

Electromechanical processes during the start of induction-type magnetic levitation

2025-04-20T21:06:22+03:00

Purpose. A study of induction-type magnetic levitation by determining the electromechanical processes that occur when a stationary inductor is connected to an alternating voltage source and the levitation of an anchor made in the form of a multi-turn short-circuited winding with an attached load. Methodology. Using a mathematical model describing an inductor and an anchor with concentrated parameters, solutions are presented for equations describing the interconnected electrical, magnetic, mechanical and thermal processes that occur in induction-type magnetic levitation. Results. The influence of the frequency of the alternating current source on the electromechanical processes of levitation, which occur at different parameters of the anchor, is established. Due to the phase delay of the induced anchor current in relation to the inductor current, an electrodynamic force directed downwards arises at certain moments of their period. The total force acting on the anchor, due to the electrodynamic component, is of an alternating nature with a predominance of the positive, upwardly directed component, which causes pulsations of the anchor speed. Originality. The force acting on the anchor due to the electrodynamic component is of an alternating nature with the positive component directed upwards dominating. The resulting oscillatory damping mechanical process occurs with an increase in the oscillation period and a decrease in its amplitude. Practical value. It has been established that the maximum value of the lifting force acting on the anchor is achieved at an alternating current frequency in the range from 75 to 125 Hz, and the highest value of the steady-state levitation height is realized for an anchor similar to an inductor at a frequency of 75 Hz. References 37, figures 6.