Electrical Engineering & Electromechanics

Disinfectant treatment of liquids with high specific electrical conductivity by high-voltage nanosecond pulses with a subnanosecond front

M. I. Boiko — 2025-09-02

Purpose. The purpose of the work is to determine, using computer modelling, energy-efficient modes of disinfecting treatment of water-containing liquids with high specific electrical conductivity using high voltage nanosecond pulses with a subnanosecond front including pulsed discharges in gas bubbles. Methods. We considered methods of obtaining high-voltage nanosecond pulses with sub-nanosecond fronts. To achieve this goal, we used computer simulation using Micro-Cap 12. We also used analytical and empirical formulas for calculating the electric field strength, inductive and resistive phases of energy switching from a capacitive source to resistive-inductive loads. We have applied the method of comparing calculated and experimental results. Results. Energy-efficient modes of disinfecting treatment of water-containing liquids with high specific electrical conductivity using nanosecond discharges with a subnanosecond front in gas bubbles are such modes when the active resistance of the treated liquid is 10–40 W. In this case, the lumped inductance of the discharge circuit during liquid treatment does not exceed 2 nH, the capacitance of the layer of the treated liquid is 3.6–14 pF with an amplitude of pulses from a high-voltage low-resistance source of at least 30 kV and a pulse frequency of 1500–2000 pulses per second. With an increase in the active resistance of the liquid within the specified limits, the amplitude of the voltage on the layer of the treated liquid increases under other unchanged conditions, including with an unchanged amplitude of the voltage from the source. The voltage amplitude on the layer of the treated liquid with such an increase can exceed the voltage amplitude from the source by 1.6 times, and exceed the voltage on the reactor as a whole (the series connection of the bulk streamer and the water layer). This happens due to the presence of a lumped inductance in the discharge circuit, in which energy is stored during discharge. Scientific novelty. We have shown the possibility of using nanosecond discharges with sub-nanosecond fronts in gas bubbles for energy-efficient disinfection of liquids, including those with high specific electrical conductivity. In this case, a plasma electrode – a volumetric streamer – acts as a high-voltage electrode in the disinfection of liquids. Practical value. The obtained of the computer modelling results confirm the possibility of industrial application of nanosecond discharges with a sub-nanosecond front for disinfection and purification of water-containing liquids with high specific electrical conductivity. References 23, figures 13.

Analysis of energy characteristics of a transistor pulse generator in the process of electric spark dispersion of current-conductive granular media

O. I. Khrysto — 2025-09-02

Introduction. Studies of electrophysical and technological aspects of electric discharge in reaction chambers with granular metal loading to obtain its highly dispersed states have been conducted for many decades, however, the power sources of electric spark dispersion installations today remain mainly classical in terms of the method of generating current pulses on the electric spark load. The main problem of using powerful current pulse generators and reaction chambers with a plane-parallel electrode system is to imitate the principle of the thermo-explosive mechanism of developing an electrical breakdown of dense intergranular gaps, which leads to deterioration of the dispersion of the eroded material, and the use of smaller energy ranges (<1 J) in such installations is complicated by the electrophysical limitations of the existence of plasma channels and the loss of energy efficiency of the electric spark treatment process. Goal. Research on the energy efficiency of the electric spark dispersion process of heterogeneous conductive granular media in a reaction chamber with a cylindrical electrode system, provided that it is powered by a transistor pulse generator. Results. Specific energy consumption in the process of electric spark dispersion of aluminum and titanium granules was determined, which correlate with the average power consumption indicators of processing depending on their bulk volume within a certain configuration of the electrode system. Scientific novelty. The flow of current through ohmic contacts until the formation of the main discharge in the intergranular volumes of the reaction chamber causes a voltage drop across the inductance of the discharge circuit, which accordingly reduces the amplitude of the applied voltage to the interelectrode gap, due to which the maximum of the average power consumption characteristic of the transistor pulse generator, which occurs before the beginning of the saturation section of the effective frequency curve of the discharge pulses, corresponds to the most consistent mode of energy input into the electric spark load. The practical value of the considered model of the electric discharge installation proves the feasibility of its use for the tasks of electric spark treatment of conductive granular media. References 21, tables 2, figures 7.

Features of designing high-voltage overhead power lines in an underground collector

S. Yu. Shevchenko — 2025-09-02

Problem. Protection of HV overhead power lines (OPL) from external atmospheric and military influences and reduction of their hazardous electromagnetic radiation is possible if they are made in a compact form and placed in an underground collector. But to ensure high capacity and reliable operation of such compact HV OPL, it is necessary to improve the existing designs of their current-carrying elements. The goal of the work is to determine promising design parameters of busbars of compact high-voltage overhead power lines laid in an underground collector. The methodology for calculating permissible long-term currents of HV OPL laid in an underground collector is based on the analytical model proposed by the authors for describing the processes of mass and heat transfer in the air of an underground collector. Scientific novelty. For the first time, the possibility of efficient use of HV OPL in an underground collector conditions is substantiated and the conditions for their reliable transmission of electric energy with increased capacity are determined. This is achieved through the use of rectangular flat vertical conductive busbars with an increased surface area and providing better convective heat exchange compared to traditional round wire, as well as by determining the rated current for such overhead lines at a reduced ambient temperature (15 °C), which is typical for operating conditions in underground collectors (25 °C) adopted for overhead lines located outdoors. Practical value. The use of the proposed HV OPL laid in an underground collector should ensure reliable transmission of electrical energy, sufficient throughput and increased protection from external factors while reducing the electromagnetic impact on the environment (due to a significant reduction in the interphase distance from 3–4 m to 0.3–0.6 m for 110 kV HV OPL), and has advantages over SF6-insulated cable lines and cable lines characterized by an increased insulation cost). References 36, table 1, figures 6.

The influence of the design of the stator winding of a synchronous-reactive generator on increasing its energy efficiency

O. B. Iegorov — 2025-09-02

Introduction. Increasing the energy efficiency of electric generators is a pressing task for various areas of energy, in particular for autonomous systems and transport. Synchronous-reactive generators (SRGs) are becoming increasingly widespread due to their simple design, absence of magnets and mechanical contacts, and high reliability. The task of the proposed work is to study the influence of the design of the double winding of the stator of a SRG on its energy characteristics, determine the optimal parameters of the mutual arrangement of the windings, and develop recommendations for increasing the generator efficiency. Goal. Analysis of the influence of the design of the double winding of the stator of a SRG on the output energy characteristics and determine recommendations when designing this type of electrical machines. Methodology. The analysis was carried out using numerical modeling by the finite element method in the ANSYS Maxwell environment. Various options for the mutual arrangement of the main and excitation windings in the generator stator were considered. Results. The influence of the single-layer and double-layer winding design on the output characteristics of the generator was studied. It was found that a two-layer arrangement with a phase shift of 2 slots provides minimal torque ripple, improves the stability of the generator operation and helps to increase the efficiency to 92.5 %. Scientific novelty. For the first time, the effect of the phase shift of the windings on electromagnetic processes in the SRG has been studied in detail, which allows optimizing its design and improving operational performance. Practical value. The results can be used in the design of new generators with improved characteristics for use in wind power, diesel generator sets and autonomous electrical systems. References 19, table 1, figures 12.

Regulation characteristics of a step-down pulse regulator in continuous and discontinuous conduction mode

V. Y. Romashko — 2025-09-02

Introduction. Pulse regulators (PRs) are widely used to regulate and stabilize the supply voltage of DC consumers. The main characteristic of any regulator is its regulation characteristic. In the general case, two modes of PR operation are possible: continuous conduction mode and discontinuous conduction mode in the inductance of the PR. Problem. When the PR transitions from one operating mode to another, its regulation characteristics change. In the continuous conduction mode, the regulation characteristic is a function of one variable. In the discontinuous conduction mode, the regulation characteristic becomes a function of two variables. Therefore, in such a mode, PR is described by a family of regulation characteristics. The goal of the work is to develop a mathematical model that describes the operation of the controller in both continuous and discontinuous conduction modes, as well as to determine the control characteristics that are valid for both of these modes. Methodology. In the work, using the example of a step-down type PR, the conditions for the PR transition from one operating mode to another are determined, as well as the dependence of the PR output voltage on the duration of the pause in the inductance current. Results. The influence of the parameters of the PR elements on the pause duration is analyzed. A graph of the family of PR control characteristics is constructed, which is valid for both continuous and discontinuous conduction modes. Scientific novelty. It is shown that when PR transitions to discontinuous conduction mode, its control characteristics shift towards higher output voltages. This shift is greater, the longer the pause duration in the inductance current. Practical value. It is determined that the specified ripple coefficient of the PR output voltage in the discontinuous conduction mode is provided by a smaller value of the LC product of the PR elements, compared to the continuous conduction mode. References 17, tables 2, figures 5.

Wind farms integration into power system with improved location and stability problem solving

H. Hafaiedh — 2025-09-02

Problem. This article investigates as a consistent supply to satisfy rising world energy consumption, wind energy is becoming more and more important. Correct evaluation of the stability and performance of wind induction generators inside power systems remains difficult, particularly in regard to ensuring compliance with grid rules and best location. Goal. To evaluate and compare the dynamic behavior and grid compatibility of the squirrel cage induction generator (SCIG) and the doubly fed induction generator (DFIG) wind generators in various locations within the IEEE 14 bus network, and to determine the improved generator type and location. Methodology. The investigation adopts the small signal stability analysis for modeling the wind induction turbines due to its capability to assess system stability, controllability and observability. The IEEE 14 bus distribution network is modeled with wind generators interconnected at buses 10 through 14. Several parameters are analyzed under different operating conditions, including voltage, rotor angle, active power, reactive power and frequency. Results. DFIG exhibits superior performance across all analyzed parameters, particularly in maintaining grid stability and meeting grid code requirements. Bus 13 was identified as the improved integration point for wind farms using DFIG technology. Scientific novelty. The study offers a structured comparison of SCIG and DFIG using state space modeling rarely applied in a direct bus by bus comparative study within a standard distribution network. Practical value. The results help system planners choose the right wind turbine type and location, which promotes a more reliable and effective integration of renewable energy sources into power networks. References 51, tables 5, figures 7.

Maximum power point tracking improving of photovoltaic systems based on hybrid triangulation topology aggregation optimizer and incremental conductance algorithm

A. Jeridi — 2025-09-02

Introduction. Maximum power point tracking (MPPT) in photovoltaic (PV) systems has been a key research focus in recent years. While numerous techniques have been proposed to optimize power extraction, each suffers from inherent limitations that hinder their effectiveness. Problem. Environmental factors such as shading, partial shading, and low irradiance levels significantly impact PV system performance, with partial shading being the most critical and complex challenge due to its creation of multiple local power maxima. Goal. This study aims to improve MPPT in PV systems under partial shading conditions by developing a hybrid approach that integrates a Triangulation Topology Aggregation Optimizer (TTAO) with the Incremental Conductance (IC) algorithm. Methodology. Simulations were conducted in MATLAB/Simulink under four static partial shading scenarios, comparing the hybrid TTAO-IC algorithm against traditional methods like Perturb and Observe (P&O), IC and metaheuristic algorithms. Scientific novelty of this work lies in the hybrid TTAO-IC algorithm, which combines the global optimization strength of TTAO with the precision of IC, addressing the shortcomings of conventional methods. Practical value. The results show that the hybrid TTAO-IC algorithm achieves tracking efficiencies exceeding 99 %, outperforming existing methods and demonstrating robust adaptability to varying environmental conditions. References 31, tables 5, figures 15.

Optimization of combined active-passive electromagnetic shielding system for overhead power lines magnetic field normalization in residential building space

B. I. Kuznetsov — 2025-09-02

Problem. Normalization of overhead power lines magnetic field level in residential building. Goal. Normalization of overhead power line magnetic field by optimization of combined electromagnetic shielding system, consisting of active and passive parts, in residential building space based on magnetic field three-dimensional model. Methodology. Optimization of combined electromagnetic shielding system for initial magnetic field three-dimensional model solved based on multi-criteria two-player antagonistic game solution. Game payoff vector calculated based on finite element calculations system COMSOL Multiphysics package. Game solution calculated based on particles multiswarm optimization algorithms. Results. The results of theoretical and experimental studies of combined electromagnetic passive and active shielding system for magnetic field three-dimensional model in residential building from two-circuit overhead power transmission line with wires «Barrel» type arrangement presented. Scientific novelty. For the first time the method for normalization of overhead power lines magnetic field in residential building space based on optimization of combined active-passive electromagnetic shielding system for magnetic field three-dimensional model developed. Practical value. Spatial location coordinates of shielding winding, currents and phases in shielding winding of robust active shielding system, geometric dimensions and thickness of electromagnetic passive shield calculated during optimization of combined electromagnetic shielding system for magnetic field three-dimensional model. References 49, figures 13.

Improve of the direct torque control strategy applied to a multi-phase interior permanent magnet synchronous motor using a super twisting sliding mode algorithm

F. Mehedi — 2025-09-02

Introduction. Conventional direct torque control (DTC) is a superior control strategy for managing the torque of a five-phase interior permanent magnet synchronous motor (FP-IPMSM). Nevertheless, the DTC’s switching frequency results in large flux and torque ripples, which produce acoustic noise and impair control performance. On the other hand, the DTC scheme’s performance when using conventional PI controllers results in high flux and torque ripples, which decreases the system’s robustness. Goal. This work aims to use a modern variable structure control of the DTC scheme based on a super twisting algorithm in order to ensure efficient control of multiphase machine, reduce flux and torque ripples, minimize tracking error, and increase robustness against possible disturbances. Scientific novelty. We propose to use super-twisting sliding mode control (STSMC) methods of the DTC based on the space vector modulation (SVM) algorithm of the multiphase motor. Methodology. In order to achieve a decoupled control with higher performance and to ensure stability while handling parameter changes and external disturbances, a STSMC algorithm on the DTC technique incorporating the SVM algorithm was implemented in place of the switch table and PI controller. Results. The suggested STSMC-DTC based SVM approach outperforms the conventional DTC methods in achieving the finest performance in controlling the FP-IPMSM drive. Practical value. The merits of the proposed DTC technique of FP-IPMSM are demonstrated through various tests. The suggested STSMC-DTC approach reduces flux and torque ripples by roughly 50 % and 60 %, respectively, in comparison to the conventional DTC strategy. Furthermore, the proposed technique of FP-IPMSM control method is made to provide robust performance even when machine parameters change. References 24, table 2, figures 8.

Performance evaluation and analysis by simulation for sliding mode control with speed regulation of permanent magnet synchronous motor drives in electric vehicles

F. Senani — 2025-09-02

Introduction. This study introduces a sliding mode control (SMC) that utilizes multivariable system command estimation (MSCE-SMC) to create an innovative speed control system for the permanent magnet synchronous motor (PMSM). The motor operates through a 3-phase voltage source inverter when used in an electric vehicle (EV) model, with the goal of achieving fast speed regulation and high performance. Problem. The primary challenge is to achieve fast and accurate speed regulation for PMSMs while maintaining high performance, despite varying system parameters and external disturbances. The goal is to design a robust and adaptive speed control system for PMSMs using the SMC approach, which ensures precise speed tracking and high-performance regulation. Scientific novelty. The integration of MSCE-SMC approach, offering an innovative solution for speed control in PMSMs used in EVs. Methodology. SMC approach for the PMSM divides the system into 2 subsystems: electrical and speed. A d-q coordinate frame is used to model the PMSM, and its control strategy is outlined. A detailed model of the PMSM with SMC is presented after an in-depth review of the theoretical concepts and principles of sliding mode control. Results. To validate the proposed approach, MATLAB/Simulink is conducted, demonstrating the effectiveness and robustness of the method in PMSM speed regulation. The results confirm that the proposed method provides straightforward and precise control, accurate speed tracking, and high-performance regulation. It also shows adaptability to parameter variations and external disturbances. Practical value. The practical value of the proposed method is significant, as it provides a reliable and efficient control system for PMSMs. It offers precise speed control, robust performance under variable conditions, and high adaptability to external disturbances, making it suitable for real-world EV applications. References 22, table 1, figures 18.

Takagi-Sugeno fuzzy model identification using improved multiswarm particle swarm optimization in solar photovoltaics

S. Zdiri — 2025-09-02

Introduction. The particle swarm optimization (PSO) algorithm has proven effective across various domains due to its efficient search space exploration, ease of implementation, and capability to handle high-dimensional problems. However, it is often prone to premature convergence, which limits its performance. Problem. This issue becomes critical in identifying Takagi-Sugeno (T-S) fuzzy models, especially in complex systems like solar photovoltaic (PV) applications, where model accuracy is vital for tasks such as maximum power point tracking (MPPT) and shading compensation. Goal. This manuscript introduces an improved multiswarm PSO (I-MsPSO), designed to enhance search performance and robustness in identifying T-S fuzzy systems. The method is particularly suited to nonlinear modeling challenges in renewable energy systems. Methodology. I-MsPSO divides the swarm into 4 independent subswarms, each operating in a local region with specific inertia weights and acceleration coefficients. Periodic information sharing between subswarms allows the algorithm to converge collectively toward optimal solutions. A new modeling approach, specific Takagi-Sugeno modeling (STaSuM), is introduced, using I-MsPSO to determine both the structure and parameters of T-S fuzzy systems. Results. The I-MsPSO’s performance was tested on benchmark optimization problems and real-world engineering cases. Results show that STaSuM produces highly accurate and generalizable fuzzy models, outperforming existing techniques. Scientific novelty lies in the development of I-MsPSO, which enhances the traditional PSO by using 4 interactive subswarms with customized parameters, and the creation of STaSuM for advanced T-S fuzzy system identification. Practical value. I-MsPSO and STaSuM provide a powerful optimization and modeling framework, offering robust and accurate solutions for nonlinear and dynamic environments. Their structure makes them especially valuable for future applications in MPPT control, fault-tolerant modeling, and real-time optimization in PV energy systems. References 39, table 5, figures 8.