Search

The main insulation structure of the valve‐side winding of converter transformer bears the effect of AC and DC superimposed voltage during operation. The electric field intensity in the pressboard is much higher than that in the pressboard in the AC transformer. This condition increases the probability of failure of insulation structure. Therefore, the design and optimization of the main insulation structure of the valve‐side winding are keys to ensure the stable operation of converter transformer. This study establishes a model of the main insulation structure of the valve‐side winding of the ±1100 kV converter transformer. The influence of the insulating oil–paper configuration on the electric field distribution of the main insulation structure of the valve‐side winding is analysed, and then, an optimization idea is proposed. The oil–paper configuration includes two aspects: oil–paper insulation structural design and combination selection, that is, the influence of typical oil–paper structural design parameters and the aging state of different oil–paper combinations on the electric field distribution. Finally, the optimization idea of the oil–paper configuration for valve‐side winding of converter transformer is obtained, and the established model is optimized. [ABSTRACT FROM AUTHOR]

In astrodynamics, orbit cranking is usually referred to as an interplanetary transfer strategy that exploits multiple gravity-assist maneuvers to change both the inclination and eccentricity of the spacecraft osculating orbit without changing the specific mechanical energy, that is, the semimajor axis. In the context of a solar sail-based mission, however, the concept of orbit cranking is typically referred to as a suitable guidance law that is able to (optimally) change the orbital inclination of a circular orbit of an assigned radius in a general heliocentric three-dimensional scenario. In fact, varying the orbital inclination is a challenging maneuver from the point of view of the velocity change, so orbit cranking is an interesting mission application for a propellantless propulsion system. The aim of this paper is to analyze the performance of a spacecraft equipped with an Electric Solar Wind Sail in a cranking maneuver of a heliocentric circular orbit. The maneuver performance is calculated in an optimal framework considering spacecraft dynamics described by modified equinoctial orbital elements. In this context, the paper presents an analytical version of the three-dimensional optimal guidance laws obtained by using the classical Pontryagin's maximum principle. The set of (analytical) optimal control laws is a new contribution to the Electric Solar Wind Sail-related literature. [ABSTRACT FROM AUTHOR]

Currently, excessive AC loss in the rectangular winding motor used for electric vehicles poses a significant challenge, necessitating effective measures to suppress the losses. This paper focuses on the Prius IV motor, employing a finite element two-dimensional model established using JMAG software. The influence of conductor material and the number of rectangular winding layers on motor AC loss under various operating conditions is thoroughly analyzed. Maintaining a constant number of rectangular winding layers, aluminum (Al) conductors replace copper (Cu) conductors in 2-layer, 4-layer, 6-layer, and 8-layer configurations, respectively. AC losses are compared among motors with 4-layer, 6-layer, 8-layer, and 10-layer Cu rectangular windings, all having identical slot dimensions. Subsequently, the 10-layer Al conductor scheme is chosen to optimize motor design. The results demonstrate an average reduction in AC loss up to 59.24% after motor optimization, further reducing motor manufacturing costs. [ABSTRACT FROM AUTHOR]

An Electric Solar Wind Sail (E-sail) is a propellantless propulsion concept that extracts momentum from the high-speed solar wind stream to generate thrust. This paper investigates the performance of such a propulsion system in obtaining the transition from a prograde to a retrograde motion. The spacecraft is assumed to initially trace a circular heliocentric orbit of given radius. This particular trajectory, referred to as Circular Orbit Flip Trajectory (COFT), is analyzed in a two-dimensional mission scenario, by exploiting the capability of a medium-high performance E-sail to change the spacecraft angular momentum vector during its motion in the interplanetary space. More precisely, the paper describes a procedure to evaluate the E-sail optimal performance in a set of COFTs, by calculating their minimum flight times as a function of the sail reference propulsive acceleration. It is shown that a two-dimensional COFT can be generated by means of a simple steering law in which the E-sail nominal plane has a nearly fixed attitude with respect to an orbital reference system, for most of the time interval of the interplanetary transfer. [ABSTRACT FROM AUTHOR]

The Internet of Things (IoT) is introduced in systems with electrical machines, such as in electric drive systems, wind energy generating systems, and small and special machines, to remote monitor and control the operation for data acquisition and analysis. These systems can integrate with the equipment and retrofit the existing installations. At the end of the control loops there are always motors, or actuators, of big or small ratings, of rotating or linear movements, electrical or nonelectrical, which must produce the motion. This article analyses selected aspects of research and applications of IoT-based control in electric drive systems and of wind energy conversion systems with induction machines. Various applications and study cases of control systems of electrical machines with IoT technology are described. With the IoT-based control of induction machine systems operators can remotely monitor parameters and obtain accurate real-time feedback during fast changing duty cycle operation. Thus, IoT creates multipurpose instruments in the remote control of induction machines. The paper offers a comprehensive analysis of IoT-based control applications in the field of induction machines, with technical details of design, construction, experimental testing, and prototyping, that are useful to energy engineering specialists in the sector of electric drives and wind energy conversion systems. [ABSTRACT FROM AUTHOR]

The aim of this paper is to investigate the performance of a robotic spacecraft, whose primary propulsion system is an electric solar wind sail (E-sail), in a mission to a heliostationary point (HP)—that is, a static equilibrium point in a heliocentric and inertial reference frame. A spacecraft placed at a given HP with zero inertial velocity maintains that heliocentric position provided the on-board thrust is able to counterbalance the Sun's gravitational force. Due to the finite amount of storable propellant mass, a prolonged mission toward an HP may be considered as a typical application of a propellantless propulsion system. In this respect, previous research has been concentrated on the capability of high-performance (photonic) solar sails to reach and maintain such a static equilibrium condition. However, in the case of a solar-sail-based spacecraft, an HP mission requires a sail design with propulsive characteristics that are well beyond the capability of current or near-future technology. This paper shows that a medium-performance E-sail is able to offer a viable alternative to the use of photonic solar sails. To that end, we discuss a typical HP mission from an optimal viewpoint, by looking for the minimum time trajectory necessary for a spacecraft to reach a given HP. In particular, both two- and three-dimensional scenarios are considered, and the time-optimal mission performance is analyzed parametrically as a function of the HP heliocentric position. The paper also illustrates a potential mission application involving the observation of the Sun's poles from such a static inertial position. [ABSTRACT FROM AUTHOR]

Power converters generate switching common mode voltage (CMV) through the pulse width modulation (PWM). Several problems occur in the drive systems due to the generated CMV. These problems can be dangerous to the insulation and bearings of the electric machine windings. In recent years, many modulation methods have been developed to reduce the CMV in multiphase machines. Symmetrical nine-phase machines with single-neutral are considered in this paper. In this case, conventional PWM uses eight active vectors of different magnitudes in combination with two zero states in a switching cycle, and this generates maximum CMV. This paper proposes two PWM schemes to reduce the CMV in such a system. The first scheme is called active zero state (AZS). It replaces the zero vectors with suitable opposite active vectors. The second scheme uses ten large active vectors during switching and is called SVM-10L. Compared with conventional strategies, the AZS reduces the peak CMV by 22.2%, and the SVM-10L reduces the peak CMV by 88.8%. Moreover, this paper presents a carrier-based implementation of the proposed schemes to simplify the implementation. The proposed schemes are assessed using simulations and experimental studies for an induction motor load under different case studies. [ABSTRACT FROM AUTHOR]

The paper develops a model created in Simscape – SIMULINK to study the monophase transformer behaviour. The equivalent circuit topology of a typical transformer needs to implement a procedure to determine the values for equivalent circuit elements based on performance criteria. The preliminary tests need in study of behaviour 's transformers are open-circuit and short-circuit tests. The paper implements a model realised with Simscape block offered by MATLAB library used for modelling the transformer 'behaviour described on laboratory tests. [ABSTRACT FROM AUTHOR]

The transfer between two coplanar Keplerian orbits of a spacecraft with a continuous-thrust propulsion system is a classical problem of astrodynamics, in which a numerical procedure is usually employed to find the transfer trajectory that optimizes (i.e., maximizes or minimizes) a given performance index such as, for example, the delivered payload mass, the propellant mass, the total flight time, or a suitable combination of them. In the last decade, this class of problem has been thoroughly analyzed in the context of heliocentric mission scenarios of a spacecraft equipped with an Electric Solar Wind Sail as primary propulsion system. The aim of this paper is to further extend the existing related literature by analyzing the optimal transfer of an Electric Solar Wind Sail-based spacecraft with a Sun-facing attitude, a particular configuration in which the sail nominal plane is perpendicular to the Sun-spacecraft (i.e., radial) direction, so that the propulsion system is able to produce its maximum propulsive acceleration magnitude. The problem consists in transferring the spacecraft, which initially traces a heliocentric circular orbit, into an elliptic coplanar orbit of given eccentricity with a minimum-time trajectory. Using a classical indirect approach for trajectory optimization, the paper shows that a simplified version of the optimal control problem can be obtained by enforcing the typical transfer constraints. The numerical simulations show that the proposed approach is able to quantify the transfer performance in a parametric and general form, with a simple and efficient algorithm. [ABSTRACT FROM AUTHOR]

Using experiments by Sanya (18.3°N, 109.6°E) Incoherent Scatter Radar (SYISR) during 22 days, we first obtained the line‐of‐sight ion velocity in multiple directions, further calculated three‐dimensional vector velocity through least squares fitting, and subsequently derived northward neutral wind and electric fields from 150 to 500 km based on the momentum equation. In order to verify the reliability of the derived northward neutral wind and electric field, we used NCAR‐TIEGCM and HWM for comparative analysis. They had a good consistency in terms of diurnal variation and direction. The SYISR vertical ExB velocity during the daytime is larger than that of TIEGCM, and the direction reverses occur after 20:00 for both TIEGCM and SYISR. We further compared our wind data with that of ICON satellite. They showed a positive correlation of ∼0.62. We also used the ∆H method to verify our eastward electric field. They showed a roughly linear dependency, although the correlation coefficient is not very high. Plain Language Summary: In the low latitude ionosphere, neutral wind drives ions moving across the geomagnetic field line and generates electric field. Therefore, neutral wind and electric field are two key drivers in low latitude ionospheric dynamics. Monitoring both parameters is important for low latitude ionosphere investigation. However, measuring neutral wind and electric field, especially height profile in the F region, is very challenging and rare. In this paper, using the newly built Sanya Incoherent Scatter Radar, we have developed sophisticated algorithm to derive neutral wind and electric field from multiple beams SYISR measurements. Further evaluations show the data is reliable and therefore useful. Key Points: Northward neutral wind and electric field from 150 to 500 km are obtained using 22 days continuously SYISR observationsThe derived northward neutral wind and electric field are in good agreement with well‐known modelsThe results are further independently evaluated by ICON satellite and geomagnetism data [ABSTRACT FROM AUTHOR]

Electric Solar Wind Sails (E-Sails) are a new type of spacecraft propellantless propulsion system that gathers its energy from solar wind protons and is potentially useful for interplanetary missions. Although optimal interplanetary trajectories have been the subject of thorough research, the substantial variability of the solar wind necessitates the adoption of active guidance strategies, an area that has received significantly less scholarly attention. This paper proposes guidance algorithms for E-Sails based on Model Predictive Control (MPC), a modern control methodology based on online re-planning of the trajectory. To this end, first, properties of E-sail time-optimal orbits are studied applying Pontryagin's Minimum Principle, and then time-optimal orbits for missions to Mars and Jupiter are computed via direct transcription methods. Next, solar wind perturbations are modeled, posing a challenging saturation problem due to their high variability. Guidance strategies based on Shrinking Horizon and Receding Horizon Model Predictive Control (RHMPC) are developed, analyzed and compared using Monte Carlo simulations, successfully implementing MPC to E-sail guidance. Lastly, the RHMPC strategy is successfully tested with accurate historical solar wind data from the WSA-Enlil model. • Solar wind fluctuations implies need of guidance in E-sail interplanetary missions. • Optimal planning for E-sails is performed using direct and indirect methods. • Control saturation due to solar wind pressure is reduced by leaving control margins. • Model predictive control guidance methods are compared with Monte Carlo analysis. • Receding horizon strategy in tested with semi-empirical historical solar wind. [ABSTRACT FROM AUTHOR]

The technology of Internet of Things (IoT) can be integrated with systems of electrical machines, for electric drives and wind and solar generation systems, and advance controlling and monitoring. This work presented recent research and progress of electrical drives with IoT technology, regarding design, operation, and trial of the control system for induction motors (ΙΜ). Also, the developed software code and hardware units for speed control were detailed and the results obtained from tests of performance of the ΙΜ integrated with IoT were described. With the IoT integration set-up, the operator can control the frequency values, obtain real-time feedback of the process, and monitor the system during varying loads in steady state. The operation of the ΙΜ system driven by inverter and its monitoring over IoT was proven to have high-accuracy speed control and increased efficiency at supersynchronous speeds. Thus, IoT establishes potentials to become a multipurpose tool in the industrial control of electric drives. This paper established one case study of an IoT set-up and control technique for IM, which is suitable for energy engineering experts in the field of IoT control of industrial equipment. [ABSTRACT FROM AUTHOR]

In this paper, a multi-objective allocation and scheduling of wind turbines and electric vehicle parking lots are performed in an IEEE 33-bus radial distribution network to reach the minimum annual costs of power loss, purchased grid energy, wind energy, PHEV energy, battery degradation cost, and network voltage deviations. Decision variables, such as the site and size of wind turbines and electric parking lots in the distribution system, are found using an improved golden jackal optimization (IGJO) algorithm based on Rosenbrock's direct rotational (RDR) strategy. The results showed that the IGJO finds the optimal solution with a lower convergence tolerance and a better (lower) objective function value compared to conventional GJO, the artificial electric field algorithm (AEFA), particle swarm optimization (PSO), and manta ray foraging optimization (MRFO) methods. The results showed that using the proposed method based on the IGJO, the energy loss cost, grid energy cost, and network voltage deviations were reduced by 29.76%, 65.86%, and 18.63%, respectively, compared to the base network. Moreover, the statistical analysis results proved their superiority compared to the conventional GJO, AEFA, PSO, and MRFO algorithms. Moreover, considering vehicles battery degradation costs, the losses cost, grid energy cost, and network voltage deviations have been reduced by 3.28%, 1.07%, and 4.32%, respectively, compared to the case without battery degradation costs. In addition, the results showed that the decrease in electric vehicle availability causes increasing losses for grid energy costs and weakens the network voltage profile, and vice versa. [ABSTRACT FROM AUTHOR]

The electrically assisted forming (EAF) is a hybrid manufacturing process that utilizes electric current energy to improve the productivity and efficiency of the forming process. Many studies have been accomplished to investigate the effect of process parameters on its forming abilities, including pulse current effect, grain size, and current duration. There is currently a lack of agreement on the underlying mechanisms of the electroplastic effect to the formability of metallic materials through EAF, specifically on the Joule heating and electric wind's contributions. One promising solution to this dilemma is the application of computer simulation techniques for a better understanding of the physics of EAF. Therefore, this paper provides a brief review of the previous research studying the modeling of EAF and offers new solutions aiming to further the understanding of the underlying physics of this process through computer simulation approaches. [ABSTRACT FROM AUTHOR]

With the incorporation of renewable energy, load frequency control (LFC) becomes more challenging due to uncertain power generation and changeable load demands. The electric vehicle (EV) has been a popular transportation and can also provide flexible options to play a role in frequency regulation. In this paper, a novel adaptive composite controller is designed to solve the LFC problem for the interconnected power system with electric vehicles and wind turbine. EVs are used as regulation resources to effectively compensate the power mismatch. First, the sliding mode controller is developed to reduce the random influences caused by the wind turbine generation system. Second, an auxiliary controller with reinforcement learning is proposed to produce adaptive control signals, which will be attached to the primary proportion‐integration‐differentiation control signal in a real‐time manner. Finally, by considering random wind power, load disturbances and output constraints, the proposed scheme is verified on a two‐area power system under four different cases. Simulation results demonstrate that the proposed adaptive composite frequency control scheme has a competitive performance with regard to dynamic performance. [ABSTRACT FROM AUTHOR]

This paper presents a comparison of an AC radial flux interior permanent magnet (IPM) motor with the distributed winding (DW) and concentrated winding (CW). From time to time, manufacturers of electric vehicles change the design of electric motors, such changes may include changing the DW into CW and vice versa. A change to the winding in a radial permanent magnet synchronous motor may lead to a change in motor parameters during motor operation and /or change in the distribution of the magnetic field and thermal circuit of the electrical machine. The electromagnetic analysis, efficiency map, mechanical stress, and thermal analysis of the machine with the DW and CW are presented in this paper. This article describes the advantages and disadvantages of selected stator winding designs and helps understand manufacturers' designers how the DW and CW play a key role in achieving the designed motor's operational parameters such as continuous performance. Analyzing the performance of both machines will help identify their advantages and disadvantages with regard to thermal phenomena, magnetic field and operational parameters of the presented IPM prototypes. Both prototypes are based on commonly used topologies such as 12/8 (slot/pole) and 30/8 (slot/pole) IPM motors consisting of magnets arranged in a V-shape. The AC IPM motor was designed for an 80 kW propulsion system to achieve 170 N·m at a base speed of 4 500 rpm. Modern CAD tools are utilized throughout the numerical computations based on 2-D finite element methods. Selected test data are used to verify and validate the accuracy of finite element models. [ABSTRACT FROM AUTHOR]

A linear theory of the generalized Rayleigh‐Taylor instability (GRTI) is derived which includes ion inertia and acceleration forces, as well as E region drivers: the zonal neutral wind and plasma drift. This is in contrast to the F region drivers (aside from gravity): the meridional neutral wind and the meridional/vertical plasma drifts. Both a local theory and a flux‐tube integrated theory are presented with application to the onset of ionosphere irregularities associated with equatorial spread F. Inertia and acceleration forces do not affect the growth rate of the GRTI for nominal ionospheric conditions, but the E region zonal drifts can significantly increase or decrease the growth rate of the GRTI in the equatorial and mid‐latitude ionosphere depending on their direction. Plain Language Summary: The equatorial ionosphere often develops electron density irregularities at night in the altitude range 300–1,000 km. This phenomenon is known as equatorial spread F. A leading candidate to explain the generation of these irregularities is the generalized Rayleigh‐Taylor instability. In this paper we re‐examine this instability and include terms that have been neglected in past studies: ion inertia, acceleration forces, and E region drivers (i.e., the neutral wind and electric field in the altitude range 100–150 km). It is found that inertia and acceleration forces do not affect the growth rate of the instability under normal ionospheric conditions, but E region drivers can increase or decrease the growth rate of the instability and extend the range of the instability to higher altitudes. Key Points: E region drivers (zonal neutral wind and plasma drift) can increase or decrease the growth rate of the generalized Rayleigh‐Taylor instability (GRTI)Inertia and acceleration forces do not significantly affect the growth rate of the GRTIE region drivers can cause instability at high altitudes (>1,000 km) which map to the mid‐latitude ionosphere [ABSTRACT FROM AUTHOR]

Summary: Renewable energy resources have a remarkable landmark across the world to provide electricity to the consumers without any inadequacy in the energy market. The utilization of renewable energy sources in electric vehicle charging stations is among the most prominent area of research in developing countries. This paper analyses techno‐economic and environmental factors of hybrid solar wind vehicle charging stations at the highway of Southern Tamil Nadu, India. The sensitivity analysis is performed in the design of a charging station at the following highway locations at Madurai, Virudhunagar, Sattur, Kayathar, and Tirunelveli. The locations are chosen in such a way that, wind and solar potentials are having contradictory nature in the specified locations. The charging station is designed and optimized as ON‐grid strategy using the hybrid optimization model for electrical renewable tool. The designed system is capable of charging 17 electric vehicles at day from forenoon 6:00 am to evening 6:00 am The attainment of the proposed designed system proves that Virudhunagar shows less net present cost with $303 291.26 and cost of energy as $0.072/kWh with 50% reduction in emission. Moreover, with a focus on economic analysis and Madurai produces 70% more electrical energy than other selected locations. Further, the performance analysis of the system is also studied and it shows more reliable results and is feasible considering both economic and technical studies. [ABSTRACT FROM AUTHOR]

The paper presents the steady-state analysis of a new hybrid synchronous machine with a higher reluctance to excitation power ratio. The machine comprises a round rotor and a salient-pole machine elements that are mechanically coupled together and integrally wound. In each stator, there are two sets of identical poly-phase windings identifiable as the primary and secondary windings which are electrically isolated but magnetically coupled. The primary windings are connected in series between the two sections of the hybrid machine while the secondary windings are connected in anti-series and terminated across a balanced capacitor bank. The hybrid machine exhibits a special feature that when running at the synchronous speed, its effective XD/XQ ratio can be amplified and hence its output by the tuning of the variable capacitance bank which capacitive reactance XC neutralizes only the quadrature axis reactance XQ while the direct axis reactance XD remains unaffected. It is shown that at XD/XQ = 3, the reluctance component of the output power is 2.5 times the excitation power. The calculated and the measured results from the machine are in good conformity. [ABSTRACT FROM AUTHOR]

Within the CERMISO INCDMTM Bucharest center, the study of drones requires, among other processing equipment, the use of a high-volume industrial plastic 3D printer. This is the reason why the center was equipped with a JCR 1000 Dual printer with a 1000 x 600 x 600 mm printing volume (insulated and heat-controlled), two printheads, closed enclosure and heatcontrolled bed. In the period of about two years since the acquisition of this industrial equipment, we have performed tests, trials and research on this model of 3D printer, so we have reached a series of problems that can be solves for a more safe and precise operation. The problems and the related solutions found are presented in this paper. There are 5 sensitive areas that affect working with this equipment: a. Calibration of the printing bed in 49 points; b. ABS and PLA wire aging too fast inside the equipment driving pipes; c. Loss of reference during printing in case of the appearance of voltage spikes and transients; d. Problems of total job loss due to power failure; Given our rich experience with such printers, the paper will present a number of viable solutions to these problems. These proposals are made in such a way as to require a minimum of investment and effort. [ABSTRACT FROM AUTHOR]

Aim of this paper is to attain the highest voltage sag and swell compensation using a direct converter-based DVR topology. The projected DVR topology consists of a direct converter with bidirectional switches, a multi winding transformer with three primary windings and secondary winding and a series transformer. When voltage swell occurs in a phase, the same phase voltage can be utilized to mitigate the swell as huge voltage exists in the phase where swell has occurred. So it is possible to mitigate an infinite amount of swell. In all the DVR topologies, the converter is only used to synthesize the compensating voltage. The range of voltage sag mitigation depends upon the magnitude of input voltage available for the converter. If this input voltage of the direct converter is increased, then the range of voltage compensation could also be increased. Input voltage of the direct converter is increased using the multi winding transformer. The direct converter is synthesizing the compensating voltage. This compensating voltage is injected in series with the supply voltage through the series transformer and the sag is mitigated. In this proposed topology, the input voltage for the direct converter is increased by adding the three phase voltages using a multi winding transformer. Thus the voltage sag compensating range of this topology is increased to 68% and the swell compensating range is 500%. Ordinary PWM technique has been used to synthesize the PWM pulses for the direct converter and the THD of the compensated load voltage is less than 5%. This topology is simulated using MATLAB Simulink and the results are shown for authentication. [ABSTRACT FROM AUTHOR]

This paper deals with a family of two‐ and three‐windings coupled inductor‐based impedance source networks. They have been basically derived from the successful quasi‐Y‐source network (q‐YSN) by replacing one of its capacitors with a diode with different combinations of coupled inductors and called diode assisted impedance source networks (DA‐ISNs). The general three‐windings version, called diode‐assisted Y‐source network (DA‐YSN), as the origin of all other simplified versions, is thoroughly investigated from various points of view. From the voltage gain characteristics aspect, it offers a higher voltage gain with the same number of elements as the conventional q‐YSN. Lower magnetizing and input current ripples show the higher power density of DA‐YSN in comparison to q‐YSN. The effectively reduced voltage stress and the total value of capacitors, and a considerable decreased conversion loss of the magnetic element are the other attractive features of DA‐YSN. With the advantages of a low input current ripple and a high voltage gain, DA‐ISNs can be suitable choices for renewable energy and distributed power generation systems. Operating principle, circuit analysis, and parameters design guidelines for DA‐YSN are thoroughly investigated. Also, the small‐signal modelling, analysis and the controller design are presented in this paper. Finally, the theoretical properties of DA‐YSN are scrutinized by performing extensive experiments on a 200 W laboratory prototype. [ABSTRACT FROM AUTHOR]

The paper describes a diagnostic system for electromechanical equipment with a decision-making block based on a neural network. An asynchronous gear drive was used as a control object. Decision making was carried out on the basis of a comprehensive analysis of vibration data (from the gear drive) and the current consumption of the induction motor. Vibration velocity, vibration acceleration and current in the phases of the stator winding of the drive electric motor are distinguished as diagnostic signs. The work shows the possibility of increasing the efficiency of diagnostics of electromechanical equipment by using complex analysis with the use of an intelligent decision-making unit. Analysis of the results of the neural network operation with the received vibration and current data showed that with a smaller number of iterations (training time) (by 40 %), 97.9 % of correct answers and a lower error value (by 12 %) were obtained. [ABSTRACT FROM AUTHOR]

Purpose: Nowadays there is still low awareness of creating specific supply chain hybrids in a planned manner. This paper focuses on a hybrid of the gresilient chain, which reflects the trend to act for the well-being of the environmental to eliminate disruptions in the flow of goods. The aim of the study is to determine the interdependence of the factors shaping the resilience of the supply chain and to determine which of them contribute the most to the creation of a green chain. Design/methodology/approach: AHP and DAMATEL were used as research tools. A study focused on the cognitive chain is extremely interesting, because it is a global chain in which the main coordinator is relatively small. The subject of the research is the international supply chain of a company that conducts research on engine oils, coolants and fuels for gas engines driving turbines, electric and wind turbines, hydraulic transmissions, etc. Findings: As a result, among other things, it was established, that speed is the factor that is most sensitive to the influence of other factors and, at the same time, the most important from the point of view of recipients. In addition, it was proven that redundancy is essential for creating resilience in the analyzed chain, while transparency is necessary for creating the green chain. It has also been shown that redundancy and cooperation work simultaneously to a great extent for the benefit of both chains. Research limitations/implications: Every supply chain requires a separate study. Practical implications: The results can help managers in implementing the gresilient strategy or in modifying it if it has already been implemented. The work carried out may contribute to the creation of a general matrix containing paths to the expected types of supply chains, taking into account the specificity of input and output connections. Social implications: Gresilient chains are part of the idea of corporate social responsibility. Originality/value: From the standpoint of building up resilience, this is an interesting case, because it is the discussed case does not fit into the concepts of popular models in which agility is promoted as the one that guarantees the resilience of the chain. The study is an expanding knowledge in the field of the gresilient chain, in which research is lacking due to the initial stage of science in this area. [ABSTRACT FROM AUTHOR]

Copyright of Romanian Journal of Civil Engineering / Revista Română de Inginerie Civilă is the property of Matrix Rom and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents a detailed analysis of the electromagnetic force and vibration behavior of a new axial flux permanent magnet (AFPM) machine with a yokeless stator and interior PM rotor. Firstly, the configuration of an AFPM machine with a dual rotor and a sandwiched stator is introduced, including the structural design, fixation of the yokeless stator and segmented skew rotor structure. Then, the influence of anisotropic material and a fixed structure on stator modes is analyzed, including elastic modulus, shear model, the skew angle of slot and the thickness of stator yoke. Furthermore, a new non-equally segmented skew rotor structure is proposed and calculated for the reduction in vibration based on the multiphysics model. Three different segmented skew rotor schemes are compared to illustrate the influence of reducing vibration and noise. The predicted results show that the effect of the non-equally segmented skew rotor on reducing vibration is better than the other two schemes. Finally, a 120 kW AFPM motor is experimented with and the result matches well with the predicted data. The vibration performance of the AFPM motor with a dual rotor and sandwiched yokeless stator is revealed comprehensively. [ABSTRACT FROM AUTHOR]

China uses subsidies extensively to take a leading role in the global markets of green-tech products such as battery electric vehicles and wind turbines. Against the background of the current EU investigations into Chinese subsidies in these sectors, this article takes a careful look at the Chinese subsidy system and provides new data on direct government subsidies to leading Chinese producers of electric cars and wind turbines. Extensive government support has allowed Chinese companies to scale up rapidly, to dominate the Chinese market and to expand into foreign markets. The article concludes that the EU should use its strong bargaining power due to the single market to induce the Chinese government to abandon the most harmful subsidies. [ABSTRACT FROM AUTHOR]

An electric solar wind sail (electric sail or E-sail) is a new type of propulsion system that does not require propellant. This paper proposes a nonlinear model predictive control law based on deep learning to control the attitude of a barbell electric sail. A barbell E-sail is composed of two tip satellites connected via long conductive tethers to a central insulated confluence point. The two tethers are insulated from each other at the confluence point such that the voltages of the two tethers can be independently controlled. The attitude dynamics of the system is modelled using a nonsingular description of tether orientation. To reduce online computation loads, the proposed control scheme has a two-stage design, namely, an offline stage and an online stage. In the offline stage, a large amount of data is generated using the nonlinear model predictive control law and then taken as a dataset to train a deep neural network. In the online stage, feedback control of the system attitude is achieved with extremely low computational cost by performing real-time mapping from the system state to the control output using the trained deep neural network. Finally, the efficacy and performance of the proposed deep learning-based control law are demonstrated via numerical case studies. • Attitude dynamics of an E-sail system is modelled by a nonsingular formulation. • Nonlinear dynamics and inherent constraints of the system are accounted for. • Extremely low computational cost of feedback control is achieved using a DNN. [ABSTRACT FROM AUTHOR]

Controlling the highest temperature in the windings is the primary objective of transformer thermal design to guarantee designed transformer thermal life expectancy. Temperature rise test results of a transformer with computational fluid dynamics (CFD) modelling results are compared here to determine typical OD and ON flow rates in the transformer. It then presents CFD studies that compare the thermal behaviour of two types of disc‐type windings. The S disc‐type winding refers to one that has only axial cooling ducts and physically resembles a layer‐type winding. The other type is of conventional disc‐type winding. The S disc‐type winding shows robust thermal performance due to its quasi‐uniform flow distributions in the axial cooling ducts, irrespective of the total oil flow rates or the cooling modes. In contrast, the conventional disc‐type windings converted from the S disc‐type winding experience uneven flow distributions in the radial cooling ducts that can cause localised overheating. Control of oil flow distribution in conventional disc‐type windings is found critical for its thermal design. Heat transfer for the S disc‐type winding is further enhanced by axially partitioning the winding into multiple sections, which is optimized based on theoretical analyses and is then verified by CFD modelling. [ABSTRACT FROM AUTHOR]

This paper investigates the spin rate bounds, the configuration stability subject to the solar wind fluctuations, and sail angle control of an electric solar wind sail (E-sail) by a high-fidelity tether dynamic model. This model describes the elastic deformation of tethers with inter-connected 2-noded tensile elements discretized by the nodal position finite element method. The E-sail is assumed to be an axisymmetric system spinning in the plane normal to the heliocentric ecliptic plane. The upper and lower spin rate bounds are revisited to reveal the physics that dictates these bounds and analytic expressions are provided to ensure the proper operation of E-sail. Then, the influences of the solar wind fluctuations on the configuration stability of the E-sail are investigated by parametric analysis with different E-sail configurations, sail angles, and spin rates. Finally, an alternative sail angle control strategy for the E-sail is proposed by applying control force at the remote units with a simple PD control. Numerical analysis demonstrates that the sail angle of E-sail can be controlled quickly by the control law at the remote units with a high-precision. • Derived a new theoretical lower bound of spin rate for E-sail with auxiliary tethers. • Analyzed structural dynamics of E-sail by a high-fidelity tether dynamic model. • Revealed necessity and effectiveness of auxiliary tethers by tether dynamic perspective. • Controlled sail angle by applying control forces at remote units only. [ABSTRACT FROM AUTHOR]

We show that the color |$N$| -dependent area law falloffs of the double-winding Wilson loop averages for the |$SU(N)$| lattice gauge theory obtained in previous works are reproduced from the corresponding lattice Abelian gauge theory with the center gauge group |$Z_N$|⁠. This result indicates the center group dominance in quark confinement. [ABSTRACT FROM AUTHOR]

• This paper studies the stability issues of the aggregated model of Wind Farm (WFs) and charging stations. It results in undesirable operation and malfunction in the system to cause instability. • To avoid stability issues and enhance stability, the test system has been carried out by incorporated stabilizer and compensator and different combinations under various operational conditions. • The rotor speed deviation is the objective function for particle swarm optimization and is formulated based on the transient stability analysis. The stability is conducted by creating a 3-ϕ fault. • From the results, it is also noticed that oscillations in the system are minimized, damping in the system is enhanced, transient stability is enhanced and also the capability of aggregated model for EVs and WFs under extreme disturbances is intensified by optimizing the coordinated controllers' parameters. • The effectiveness and robustness of the proposed approaches are verified on the IEEE-11 bus test system. This paper analyses an aggregated battery charging model for Electric Vehicles (EVs) and Wind Farms (WFs). The effects of EVs and WFs on stability have become a substantial problem with comprehensive apprehension due to the intermittence power flow and irregular battery-charging behaviour. It results in undesirable operation and malfunction in the system to cause instability. In this work, it is integrated with various controllers to enhance the stability. The rotor speed deviation has been considered an objective function with various constraints for particle swarm optimization to provide the controller's optimized value and combination. It also studies the influence of transient stability problems using time-domain simulation. From stability analysis, coordinated controllers intensify the capability of SGs and WF under extreme disturbances. The effectiveness and robustness of the proposed approaches have been verified using the IEEE-11 bus test system. [Display omitted] [ABSTRACT FROM AUTHOR]

Assessment of solar and solar wind parameters driving the ionosphere model is essential for prediction of the ionospheric weather. In the present paper impact of the different solar, interplanetary and geomagnetic parameters on the global electron content (GEC) during intense space weather storms is investigated. Hourly GEC values are calculated from JPL global maps of total electron content GIM-TEC from 1995 to 2023. The sample comprises 90 intense storms from 1995 to 2023 associated with monthly peak of the weighted accumulation of the geomagnetic Apo (τ, t) index exceeding 90 nT. The 27 day weighted accumulation of the solar sunspot numbers SSN2 (τ), solar radio flux F10.7 (τ), the solar hydrogen emission Lyman _ α (τ) and the composite magnesium MgII (τ) indices are explored as precursors of GEC enhancements. As distinct from the positive ionosphere storm, the solar wind speed Vsw , the solar wind electric field Ey , merging electric field Em and Apo (τ, t) indices proved to be effective as potential drivers of the negative GEC depletion. The positive and negative dGEC deviations from hourly GEC are produced by subtracting a quiet reference GECav averaged during 24h prior the storm normalized by GECav. The hourly storm profiles Vsw(t) , Em(t) , Ey(t) , Apo (τ, t), Dst(t) , GEC(t) and dGEC(t) were reduced by method of superposed epochs. The zero epoch t 0 = 0 was taken at the peak Apo* (τ, t 0) and the storm time lasted for 48h from −12h prior t 0 and 35h afterwards. The best correlation of the positive storm dGECp amplitude is obtained with MgII (τ) and the negative storm dGECn with E m * and Apo* (τ, t 0) which are used to derive characteristics of five key points of storm-time dGEC (t) model: 1 – onset of the storm profile t 1 = t(dGECp) ; 2 – the amplitude dGECp max and its time t 2 (dGECp max); 3 – the time of transition t 3 (dGEC = 0) from the positive to negative (±) GEC storm; 4 – minimum negative disturbance dGECn min and its time t 4 (dGECn min), 5 – the end of the storm profile t 5 (dGECn). Analytical model of dGEC (t) is derived with Epstein step functions fitting 5 key points. Deviations dGEC (t) are inverted to GEC (t) using quiet reference pre-storm GECav. The model is validated for three intense storms on 26–28 February, 23–25 March and 23–25 April 2023. The results show improvement of dGEC forecast with RMS error reduced from 45 to 80% compared to results produced by the international reference ionosphere−plasmasphere model IRI-Plas. • Accumulation SSN2(τ), F10.7(τ), Lyman-α(τ), MgII(τ) show the best correlation of MgII(τ) with positive GEC storm. • Sample 90 intense storms for 1995–2023 are reduced by superposing with zero epoch at Apo (τ, t) > 90 nT. • Solar wind merging electric field Em proved to be the best precursor for Apo (τ , t), Dst(t) and negative GEC storm. • dGEC (t) forecasting model with MGII (τ) and Em field precursors shows RMSE improved by 45–80% compared to IRI-Plas. [ABSTRACT FROM AUTHOR]

Rare earth elements (REEs) as Dysprosium (Dy) are critical elements for the fabrication of components in many green energy technologies, from electric vehicles to wind turbines. Consequently, there is an increasing interest in creating sustainable and effective materials for the recovery and recycling of these elements. Zeolite materials have demonstrated a high affinity and selectivity for REEs. Thus, this paper aims to study the use of a synthetic LTA zeolite functionalized with nanomagnetite for Dy absorption, including a complete characterization of the synthetic zeolite, the kinetics and the factors affecting the adsorption efficiency. The maximum adsorption capacity reaches a value around 35 mg of Dy per gram of zeolite. The results from the adsorption isotherms and kinetic study revealed a good agreement with both Langmuir and Temkin models and pseudo-second-order kinetics. Furthermore, the thermodynamic analysis suggests that the adsorption of Dy onto the zeolite is a spontaneous and favorable process. The findings from this work could provide insights into the design and optimization of zeolite-based processes for REE recovery and recycling, contributing to the development of a more sustainable and circular economy. [Display omitted] • LTA zeolite functionalized with nanomagnetite was obtained by hydrothermal method. • Characterization confirms morphology, structure and functionalization of the zeolite. • Zeolite was employed to recover dysprosium through an adsorption process. • The maximum adsorption capacity of the zeolite for Dy was approximately 35 mg g−1 • Functionalization allows for easy separation from liquid solution with a magnet. [ABSTRACT FROM AUTHOR]

Capacity expansion models for the power sector are used to project future decisions over the coming decades by simulating investment and operation decisions for the use of electricity. Due to model performance constraints, these models typically do not explicitly simulate every hour within a year, but instead simulate representative time segments (groups of hours). This paper evaluates different approaches for selecting time segments across three methods: sequential, categorical, and clustering, across a wide range of time-segment quantities, for a total of 204 temporal profiles. To measure the performance of each profile's ability to accurately represent data, the root-mean-square-error of each profile's time segments are compared to the data's original hourly data. The temporal alignment across regions is also measured (i.e., how often windy days align across regions). Different spatial resolutions were applied for a subset of the temporal selection methods to investigate the impact spatial resolution has on performance. This paper provides a framework for measuring the value of different temporal selection methods and of adding more granular data to energy system models. Overall, multi-criteria clustering yields the lowest root-mean-square-error across all datasets evaluated and provides a holistic view of the intertwined relationships between renewable generation and electricity demand. • Temporal selection methods analyzed across three commonly used techniques. • Measured performance of representing model data within representative hours. • Measured temporal performance across electric load and wind and solar generation. • Clustering techniques performed better than sequential or categorical techniques. [ABSTRACT FROM AUTHOR]

A novel micro-solenoid resonator has been designed, simulated, and measured. The solenoid core consisted of a DuroidTM circuit board with a relative permittivity of 2.2. The resonator design incorporated four embedded copper vias with a radius of 125 µm and three surface conductors to form a rectangular coil. A pitch size of 250 µm was used for a 3.02 mm thick substrate. To enhance the resonator's performance at higher frequencies, a capacitance was introduced in series through the via. This additional capacitor effectively couples the inductance, resistance, and stray capacitance. The optimization of the quality factor was investigated through pole transfer analysis, resulting in an increased resonance frequency of 12.25 GHz and an elevated Q-factor of 306. Moreover, besides its very high Q-factor, this resonator offers a simplified design and easy integration. An analytical lumped circuit model was employed to investigate the design, and the measured S-parameters closely matched the analytical model and electromagnetic simulation results. The tuned resonator exhibited a superior quality factor compared to other micro-resonators. [ABSTRACT FROM AUTHOR]

Research on corona wind generation has been increasing in recent years because of its potential technological applications, particularly those related to improving heat transfer in small-scale devices. Since numerical simulations play a key role in the design of these applications, computationally efficient modeling of corona discharge is imperative. This work presents a new approach that allows rapid computation of the electrohydrodynamic (EHD) force density responsible for the generation of electric wind. Arbitrary electrode configurations can easily be dealt with in the model, since only the Laplacian electric field lines have to be determined numerically. Then, using approximated analytical approximations of the electric field intensity along the field lines, the spatial distribution of the current density and the space charge density can be easily determined. The model has been satisfactorily tested against experimental measurements of the current–voltage characteristic and the current density distribution on the cathode. Furthermore, the electric wind computed from the EHD force agrees quite satisfactorily with measurements carried out in different electrode configurations. Finally, the model has been applied to a new electrode configuration that has greater potential for heat transfer applications. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Serious requirements are put forward for aircraft electric machines (EMs) in terms of weight and size indicators. To reduce the mass of EMs, it is possible to consider aluminum windings, the density of which is 3 times less than that of copper windings. However, due to the much lower electrical conductivity of aluminum (40% less than that of copper), the overall performance of EMs with the same output parameters with aluminum windings is higher. In this regard, there is an interest in the electrical industry in increasing the electrical conductivity of aluminum windings. This problem can theoretically be solved by using carbon nanotubes (CNTs) together with aluminum. This article presents the results of a study of additive windings of aircraft EMs from a powder alloy based on aluminum with CNTs. Visual inspection shows that aluminum windings with CNTs have a 7.4 times more porous structure. The results of experimental studies show that after adding CNTs, the electrical conductivity of aluminum windings became 35% lower and the resistance 50% higher compared to aluminum windings without CNTs. Thus, in the presented work, additive aluminum windings with CNTs exhibit much worse electromagnetic properties compared to aluminum windings without CNTs. [ABSTRACT FROM AUTHOR]

This paper presents an accurate quasi-analytical approximation of frequency-dependent ac resistance of single rectangular conductors. In this work, first, a two-dimensional analytical ac resistance of rectangular conductors is derived. Unlike circular conductors, where current density distributes evenly in each layer of the conductor's cross-section, the edge effect is involved for rectangular conductors. Due to the edge effect, one cannot define an accurate boundary condition for solving the two-dimensional partial differential equation of magnetic field or current density of rectangular conductors. Hence, the calculated two-dimensional analytical current density result is not accurate and is modified and fitted on FEM simulation, taking the conductor's thickness into account using the least-square problem to improve its accuracy. Unlike numerical approaches, the proposed method yields an easy-to-use formula applicable to industrial applications in different fields. Contrary to the one-dimensional approach, which is only valid for very thin rectangular conductors, this method takes edge effect into account and can be used for any thickness (from square to very thin rectangular conductors). The proposed method can be used in applications where an accurate ac resistance of rectangular conductors over a wide frequency range is required, such as white-box modeling of power transformers and interpreting its frequency response analysis (FRA), and calculating the resistance of electric machine winding, busbars, and printed circuit board traces. [ABSTRACT FROM AUTHOR]

This paper proposes a novel brushless synchronous machine topology that utilizes stator sub-harmonic magnetomotive force (MMF) for desirable brushless operation. The sub-harmonic MMF component that is used in this novel topology is one fourth of the fundamental MMF component, whereas, in previous practices, it was half. To achieve the brushless operation, the novel machine uses a unique stator winding configuration of two sets of balanced 3-phase winding wound in 3 layers. For the rotor, additional winding is placed to induce the sub-harmonic component to achieve the brushless excitation. Unlike its predecessors, it utilizes maximum allowable space in the stator to house conductors in all of its slots. To implement the topology, 8-pole, 48-slot sub-harmonic brushless synchronous machine model has been designed. A 2-D finite element analysis (FEA) is used to simulate and validate the performance of the novel machine as a motor. The proposed topology shows better average torque than the existing sub-harmonic wound rotor brushless synchronous machine topologies. [ABSTRACT FROM AUTHOR]

• A novel market framework is presented in which a VPP formed by the WPP, EVA, and DRA bids in the DA electricity market and competes with CPPs. • Two stochastic multi-period Cournot equilibrium models are proposed based on the oligopolistic game theory in order to analyze the motivation to form a VPP. • The VPP's risk preference is considered in its bidding strategy optimization model and the CVaR is employed to measure the risks. • The Shapley value method is applied to allocate the profits among the WPP, EVA, and DRA within the VPP. This paper investigates the impacts of joint operation of wind power producers (WPPs) with electric vehicles (EVs) and demand response (DR) resources as a virtual power plant (VPP) in electricity markets. In particular, this paper aims at answering the question of whether these resources have incentives to voluntarily form a VPP to participate in the electricity market. For this purposes, two stochastic multi-period game models of the day-ahead (DA) electricity market are proposed based on the oligopolistic competition theory. The first model considers when the WPP, EV aggregator (EVA), and DR aggregator (DRA) form a VPP and bid in the DA market in a cooperative way, and the Shapley value method is applied to allocate the VPP's profit among the WPP, EVA and DRA; while the second model focuses on when they bid in the DA market in a non-cooperative way. In both models, the scenario generation and reduction technique is employed to simulate wind speed uncertainties, and a deviation penalty mechanism is applied when the WPP's actual output deviate from its cleared quantity in the market. In addition, the conditional value-at-risk (CVaR) is used to measure financial risks of the WPP and analyze its risk preference. Numerical examples show that the VPP mode can help the WPP to reduce its deviation between its actual output and cleared quantity and improve its competitiveness in the market. In addition, individual profits of the WPP, EVA and DRA will all increase in the VPP mode, which means that the WPP, EVA and DRA have high incentives to voluntarily form a VPP and participate in the electricity market. [ABSTRACT FROM AUTHOR]

Due to the environmental concerns and the high penetration of wind power (WP) and electric vehicles (EVs), reducing the generation costs and emissions, coordinating EV charging in the distribution networks, and addressing the WP uncertainty, are among the most challenging issues in power system control and operation. Hence, the multi-objective dynamic economic emission dispatch problem (MDEEDP) integrated with EVs and wind farms has become one of the hottest topics in this research area. In this paper, the MDEEDP in the presence of EVs, the random behavior of EV drivers, and WP uncertainty is solved using a new multi-objective evolutionary algorithm called the enhanced multi-objective exchange market algorithm. In the proposed algorithm, the novel point-to-point distance technique is introduced to find the Pareto front solutions set (PFSS) with a uniform and diverse distribution. Also, smart strategy management for charging and discharging EVs is proposed to smooth the load curve. The effectiveness of the proposed method and performance of the proposed smart strategy are investigated on two single-objective and multi-objective test systems, including EVs and wind farms, considering uncertainty and system constraints such as ramp rate limits. The simulation results show that the PFSS of the MDEEDP is well extracted by the proposed method while maintaining its uniformity and diversity. The presence of EVs and the application of the proposed smart strategy lead to a reduction of 2,926,497 ($) in the operation costs for test system 1, and, 38,694,698.28 ($) and 7,832,876.64 (kg), respectively in the operation costs and emissions for test system 2, assuming the same load curve throughout the year. In addition, the load factor in test systems 1, and 2 is improved by 11 and 19 percent, respectively. [ABSTRACT FROM AUTHOR]

Modern electric machines are attracting great interest from the research community as a result of the increasing number of current applications, including electric vehicles and wind power generators, among others. Different machines, power converters, and control technologies are used, and the number of sensors is usually minimized to reduce the total cost of the system. Particularly interesting are the current and speed sensors, which are essential to the normal functioning of the entire system. This work analyzes different calibration techniques of these sensors, using as a case example a five-phase induction motor drive. Experimental results are included to show the influence of calibration techniques on the system analyzed. The obtained results can be extrapolated to any other similar system. [ABSTRACT FROM AUTHOR]

In this study, the force generated by atmospheric positive and negative corona discharges was investigated using a simulation of a wire–cylinder configuration. We provided new insight into the atmospheric corona discharge by introducing a nonlinear force on the charged particles in the vicinity of the wire electrode. To elucidate the origin of both forces in corona discharges, we performed 2D simulations via COMSOL Multiphysics and MATLAB software. It was observed that the direction of nonlinear force is always from the wire to the cylinder regardless of the applied voltage polarity. It was illustrated that the corresponding nonlinear force of the positive corona is larger than that of the negative corona discharge. However, the span of the nonlinear force is greater in the negative corona discharge. The numerical simulation results showed that, in addition to the linear force (Coulomb force), a strong nonlinear force is generated around the wire electrode (powered electrode) that plays a complementary role in the production of electric wind caused by corona discharge. As this nonlinear force is limited to the vicinity of the wire electrode, it is possible to ignore the nonlinear force with a good approximation in the calculation of the total electrohydrodynamic force, but this force cannot be ignored in the process of forming the electric wind. [ABSTRACT FROM AUTHOR]

This study considers the design of a multi-link high-frequency circuit for calculating defective and defect-free insulation of mesh windings in order to increase the operational reliability of general-purpose electric machines. The object of research is mesh windings of electric machines. The problem to be solved: increasing the operational reliability of electric machines with general-purpose mesh windings by analyzing and modeling defects. The research results make it possible to model defects for the analysis of the state of insulation of electric machines with mesh windings. Special attention in the research was paid to induction motors with a worn-out resource, in particular, 4A80A4 UZ engine. The analysis includes phase-to-body capacitance, winding inductance, eddy current impedance, and winding impedance. Under the WN mode, a decrease in the impedance of the winding section from 3 % to the short-circuit mode was simulated; accordingly, the resonance frequencies for each case of 3 % were determined – 73990 Hz, short-circuit – 74450 Hz, as well as the corresponding input impedances 8938.7 and 8082.5. The corresponding voltage resonances and current resonances were also determined. Appropriate results were also given for the WG scheme. The results reported here relate to the design of the scheme and the research on the defects of the mesh winding. This contributes to the analysis of the state of insulation of mesh windings. The numerical data (resonant frequencies and input impedances) allow a better understanding of the behavior of windings in different states and degrees of defects. Given the research findings, it is possible to better identify and analyze potential defects in mesh windings, which in turn contributes to increasing the reliability of electric machines. The results of this study could be used in the field of diagnosis, service, and maintenance of electric machines with mesh windings. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Proceedings of the National Academy of Sciences of Armenia. Mechanics is the property of National Academy of Sciences of the Republic of Armenia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)