Inductive Reactance Research Articles

Selecting analytical method of leakage inductance calculation for optimizing high-voltage test transformer design

AN ACTUAL PROBLEM in transformer design is to optimize its design, since it allows you to create a competitive transformer. One of the objective functions in optimization algorithms for high-voltage test transformers is the ratio of the leakage inductive reactance of the transformer, reduced to the secondary side, to the load capacitance. Since the objective functions in the optimization procedure must be found many times, it is advisable to use approximate analytical calculation methods to calculate the leakage inductance. THE PURPOSE of the article is to analyze the error of the traditional analytical method for calculating the leakage inductance of power transformers with a rectangular axial cross-sections of the windings, and to develop a refined analytical method that takes into account the main design feature of high-voltage test transformers, which consists in the trapezoidal shape of the secondary winding cross-section. The refined method takes into account the change in the number of turns in the radial direction while maintaining the basic assumptions of the traditional method. METHODS. The error is studied by comparing the calculation results using these methods with the results of a numerical calculation of leakage inductance based on a 3D magnetostatic field, which are accepted as accurate. RESULTS. It is shown that the calculation error using the method proposed in the article is significantly reduced compared to the error of the method developed for power transformers with rectangular winding cross-sections. The ranges of changes in the relative geometric parameters of the base transformer have been determined, in which the error of this calculation method does not exceed 10%. The TGI 50/100 transformer, whose rated power is 5 kVA, was chosen as the base transformer. The developed analytical method is recommended for high-voltage test transformers optimization algorithms.

Electron series resonance excited in the 27.12 MHz magnetron sputtering discharge

Abstract Electron series resonance (ESR) excited in a 27.12 MHz magnetron sputtering discharge was investigated. By analyzing the discharge impedances, the imaginary part of the impedance was found to undergo a transition from capacitive to inductive at varying radio-frequency (RF) power, and the conditions for ESR excitation were satisfied at 27.12 MHz magnetron sputtering. By analyzing the discharge current and its higher-order harmonics, the near-sinusoidal current waveform and weak second-order harmonic were obtained, showing a weak nonlinear effect of the RF current. However, for the magnetron sputtering discharge, the nonuniform magnetic field has a significant effect on the sheath width and transverse current, making the sheath thinner and the transverse current smaller. As a result, a small capacitive reactance was obtained, and the inductive reactance was easily canceled. Therefore, the ESR excited in the 27.12 MHz magnetron sputtering was caused by the strong effect of the nonuniform magnetic field and the weak second-order current harmonic (H2). By estimating the ESR frequency ω res,B , the second-order current harmonic (54.24 Hz) was found to be responsible for ESR excitation.

Self-Adaptive Resonance Technology for Wireless Power Transfer Systems to Eliminate Impedance Mismatches

Impedance mismatching can severely decrease the power transmission capacity or even invalid the control logic of wireless power transfer (WPT) systems. To eliminate the impedance mismatch caused by various factors, such as resonant parameter drift, coupling structure misalignment and control strategy, a self-adaptive mistuning correction circuit and corresponding parameter design rules are proposed to ensure the WPT system consistently operates under resonant state, accompanying the optimal power transfer ability. Moreover, a reactive compensation circuit that can create an auxiliary voltage source by the absorbed reactive power that is introduced by impedance mismatching is designed. This source can generate a new current on the coil to bring the mismatched input current back to the resonant state, according to the current superposition principle. Unlike passive impedance network that require high parameter precision and active impedance matching strategies equipped with detection and control circuits, the proposed approach can self-adaptively eliminate either undesired capacitive or inductive reactance with two additional switches and an energy-storage capacitor, improving impedance adjusting rate and providing better system robustness. The simulations and experiments are in good agreement with the theoretical analysis. This study has potential applications in harsh environments where the system impedance and coupling strength are continuously disturbed.

Simulation of an induction generator for a wind farm

A pressing problem in the modern economy is still the problem of generating a sufficient amount of electricity. The situation is aggravated by environmental problems when using so-called carbon energy, as well as when using hydro and nuclear energy. The development of alternative sources of electricity is now impossible to imagine without the use of wind power plants. Wind energy is practically free energy, but its use involves the use of electric generators. Currently these are mainly synchronous generators, but induction (asynchronous) generators are also used. Despite the relative cheapness and reliability, however, induction generators occupy a very modest place in percentage terms among wind generators. One of the problems with using induction wind generators is that they require very significant reactive power during operation, which either comes from the network or is compensated by a capacitor bank. The latter is typical for autonomous induction generators. Computer modeling of induction wind generators is complicated by significant nonlinearity, which is caused by the magnetization curve or, what is the same, the no-load characteristics of the generator. As a rule, in computer modeling or simulation the inductive reactance of the magnetization branch is assumed to be constant, which is not entirely correct, since it is reliably known that it depends on the rotor rotation speed. A number of models of an induction generator are known, but so far there is no one most reliable mathematical model that allows computer studies of an induction generator with a squirrel-cage rotor, taking into account all its features. The MATLAB 2023b software package contains a mathematical model of an induction wind generator, which is of scientific and practical interest. The article examines the capabilities of this model, its advantages and disadvantages. The dependences of the influence of machine parameters on the generated active power and consumed reactive power were obtained, the influence of the inductive resistance of the magnetization branch and the influence of the nature of the load on the generated energy by the generator were assessed

Improved compensation networks for dynamic wireless power transfer in a multi-inductor track

PurposeThe purpose of the study is to design the compensation network of a dynamic wireless power transfer system, considering the movement of the receiving coil along an electrified track with a large number of inductors buried on the road.Design/methodology/approachA finite element model has been developed to calculate the self-inductances of transmitting and receiving coils as well as the mutual inductances between the receiving coil and the transmitting ones in the nearby and for various relative positions. The calculated lumped parameters, self-inductances and mutual inductances depending on the relative positions between the coils, have been considered to design the compensation network of the active coils, which is composed of three capacitive or inductive reactances connected in the T form. The optimal values of the six reactances, three for the transmitting coils and three for the receiving one, have been calculated by resorting to the Genetic Algorithm NSGA-II.FindingsIn this paper, the results obtained by means of the optimizations have broadly discussed. The optimal values of the reactances of the compensation networks show a clear trend in the receiving part of the circuit. On the other hand, the problem seems very sensitive to the values of the reactances in the transmitting circuit.Originality/valueDynamic wireless power transfer system is one of the newest ways of recharging electric vehicles. Hence, the design of compensation networks for this kind of systems is a new topic, and there is the need to investigate possible solutions to obtain a good performance of the recharging system.

Impacts of Epihomobrassinolide and Thiamethoxam·Flutolanil·Azoxystrobin on the Continuous Cropping Stress of Pinellia ternata

Continuous cropping (CC) stress severely limits the growth and industrial development of Pinellia ternata. Epihomobrassinolide (EBR) is a natural product that widely participates in many the physiological activities of many plants. Thiamethoxam·flutolanil·azoxystrobin (TFA) has been registered as a seed coating agent in crop production. In this work, the effects of seeds soaked with EBR, seeds coated with TFA, and their co-application on the plant growth, electrophysiological information (as physiological activities related to plant electrical signals), leaf photosynthesis, plant resistance, bulb quality, and yield of CC P. ternata were evaluated. The aim of this work is to excogitate a practicable agronomic measure for ameliorating the growth of CC P. ternata. The results show that soaking the seeds with EBR or coating the seeds with TFA could effectively enhance the plant height, leaf area, and stem diameter of CC P. ternata, promote its emergence seedling ratio, and decrease its inverted seedling ratio, and their associated application was found to be more efficient. Additionally, their associated application effectively enhanced the intrinsic capacitance (IC), intracellular water metabolism, nutrient transport, and metabolic activity and decreased the intrinsic resistance (IR), impedance (IZ), capacitive reactance (IXc), and inductive reactance (IXL). Meanwhile, their associated application could reliably enhance the photosynthetic capacity and stress resistance, and effectively improve the bulb quality and yield. This study emphasizes that the associated application of seeds soaked with a 0.004% aqueous EBR solution diluted 1000 times and seeds coated with a 24% TFA flowable concentrate at 1.6 mL kg−1 seed can be used as a novel and practicable technology for alleviating the CC stress of P. ternata and ameliorating its growth, electrophysiological information, resistance, quality, and yield.

The Behavioural Change of Distribution Networks with Increasing Circuit Length and Load

Purpose: This study investigated the behavioural change of distribution networks with increasing circuit length and load. Design/Methodology/Approach: This study employed a simulation-based experimental design using OpenDSS to model and analyse the behaviour of the distribution network under different scenarios. A combination of varying network lengths and loading levels was chosen to determine the behavioural changes of a network. A total of 100 simulations were conducted, representing 10 different circuit lengths and 10 different loading conditions. Data collection on voltage levels at various points along the circuit, focusing on the voltage at the end of the circuit was carried out. Each scenario will be modelled and analysed to study the voltage drop and stability. The simulation results were validated by comparing them with theoretical calculations and real-world measurements from similar networks. Findings: It has been shown that, for every circuit length there is a maximum load that will result in a linear relationship maintaining the correct energy balance to respond to voltage regulation and power flow. With circuit length increase, capacitive reactance reduces while resistance and inductive reactance increase leading to a more inductive circuit. Research Limitation/Implications: The research considered only changes in circuit length and loading as it was based on a simplified source-load equivalent circuit. Practical implication: It draws the attention of practising engineers and designers to be mindful of the implications of load increase and network expansions on system characteristics. It forms a guide to the limit a circuit could be extended or loaded if system balance is to be maintained. Social Implication: A stable and reliable power supply supports economic growth, public health, and safety, leading to improved quality of life. Ensuring all communities have reliable electricity fosters social equity and inclusion, promoting fairness and improving the quality of life for disadvantaged groups. Originality/Value: The novelty of this research lies in its comprehensive, realistic, and advanced approach to studying the behavioural changes in distribution networks with increasing circuit length and load. By addressing previously overlooked aspects and integrating modern computational and data analysis techniques, the study provides valuable new insights that can significantly improve the design, operation, and management of long distribution networks.

PHYSICAL INTERPRETATION OF PARAMETRIC RESONANCE BY ENERGY APPROACH

The object of study is the phenomenon of parametric resonance from the point of view of physical interpretation. The purpose of the study is to identify one of the special cases of the phenomenon of parametric resonance associated with an oscillating reference frame, when the parametric system contains time-dependent capacitive and inductive reactance. Based on physical measurements using a simple mathematical apparatus, qualitative analyzes are given that combine the harmony of mathematical and physical approaches. Parametric resonance is an extremely complex phenomenon associated with the imbalance of linear systems. Therefore, disequilibrium occurs due to small accumulations in an infinite time interval. Like small clusters, infinite time intervals are not suitable for graphical representation and physical interpretation of resonance. For this reason, the study of parametric resonance leads to formal mathematical problems that are idealized and difficulties arise when comparing them with practical ones. Theoretical methods, analyzing professional literature, also a quantitative analysis of the obtained results are used. In the radio-physical literature, insufficient attention is paid to the study of two non-stationary reactivity, although the possibilities of using a parametric circuit can be significantly expanded. The article analyzes this problem, since it was solved exclusively by physical methods.

The internal resistance of a non-ideal inductor in an RLC series circuit at resonance

The measured voltage at the inductor in an RLC series circuit connected to a sinusoidal electromotive force depends on the current and the impedance. The latter does not only include the inductive reactance only but also the ohmic resistance of the inductor. This fact has a clear consequence on the result of the measurement as the measured voltage at the inductor is not in counterphase with the measured voltage at the capacitance as shown in theory where ideal inductors are usually considered. In this work, the resistance of a coil in an RLC circuit is obtained from the direct measurements of the phase of the voltage at the coil at resonance and the resonant frequency for different values of capacitance. This value is compared with the resistance of the coil determined directly with an ohmmeter. The agreement between both values is very good. The conventional signal generator has been replaced by a smartphone which is a very familiar device for the students. The smartphone can provide the necessary voltage supply for the experiment to be carried out successfully.

Inductive Reactance Isolated Dynamic Seawater Monopole Antenna of High Efficiency

Inductive Reactance Isolated Dynamic Seawater Monopole Antenna of High Efficiency

A Novel Antenna Design of Compact HF and UHF Passive RFID Tags with Interconnected Structure for Energy Harvesting and Tracking Systems

We propose a new dual-band passive RFID tag antenna design by combining a rectangular spiral coil and patch-meander-line dipole with an interconnected structure. This design enables operation in high-frequency (HF) and ultra-high-frequency (UHF) RFID systems, suitable for energy harvesting and tracking applications. The simulations by the CST full-wave software demonstrate conjugate impedance matching between the tag antenna and two RFID tag chips. At 13.56 MHz (HF), the tag antenna exhibits an inductive reactance of 422.79 Ω, while at 922.5 MHz (UHF), it presents an impedance of 9.41+j174.96 Ω. The antenna generates a maximum magnetic field intensity of 0.5 A/m and omnidirectional electromagnetic fields with an antenna realized gain of -4.26 dBi at 922.5 MHz. We also analyze the impact of the tag antenna combination using numerical software. Furthermore, we fabricate a prototype tag antenna and validate its performance with RFID readers. The proposed tag antenna achieves the maximum read ranges of 11 cm and 6.9 m for the HF (13.56 MHz) and UHF (920-925 MHz) bands, respectively, accompanied by the energy harvesting of 1.48 volts at the HF band by the coupling magnetic field received by the HF antenna to the chip ST25DV04K at the output voltage pin.

ELEKTRİK ŞƏBƏKƏLƏRİNDƏ REAKTİV GÜCÜ KOMPENSASİYA ETMƏKLƏ İTKİLƏRİN AZALDILMASI MƏSƏLƏLƏRİNİN TƏDQİQİ

Despite the use of various methods and techniques for compensation of reactive power, this power flow maintains its presence in the network. The article discusses the issue of voltage regulation by changing the flow of reactive power transmitted along the line.For this purpose, capacitor batteries (CB) were connected to the phase of the line in series, measures to reduce the voltage losses in the lines by compensating the inductive reactance were evaluated. It has been determined that by reducing the current in network elements it is possible to significantly reduce the cross-section of lines.

A Memristive Oscillator

AbstractMemristors, or more generally “memristive systems,” are nonlinear electric components that change their resistance depending on a set of state variables. Meanwhile, negative differential resistance (NDR) is an uncommon electrical property that occurs in a few nonlinear electric components. Such a nonlinear property is now widely used in amplifiers and oscillators. It finds that one of the bilayer‐type nickel‐dithiolene complexes shows nonlinear transport with the NDR property and self‐oscillates under a bias current by simply adding a capacitor in parallel. Surprisingly, the Lissajous figure of this molecular material shows a “pinched hysteresis loop” typical of a memristor, and an inductive reactance emerges when a bias current or voltage is applied to the sample. Herein, a new type of oscillator that uses the NDR and hidden inductive properties of a memristive system is reported. The findings suggest that a memristive system can mimic other passive elements, such as an inductor, and can oscillate itself without having them in the circuit. The oscillation mechanism is straightforward and applicable to a wide variety of memristive materials, including resistors with large negative temperature coefficients, discharge tubes, and even nerve cells in the living body.

Optimizing the Design of a Dry-Type Single Phase Gapped-Core Shunt Reactor to Empower National Industries

The import dependency of essential components in our country's electrical power system poses a significant challenge, emphasizing the importance of focusing on the design, development, and maintenance of power system components, particularly shunt reactors, from an economic standpoint. Domestic production of these components contributes to employment opportunities and enhances self-sufficiency. This study aims to address these challenges by optimizing the design of a dry-type single phase gapped-core shunt reactor with a rating of 100 kVAr and 10 kV. The reactor operates at a frequency of 50 Hz and experiences a maximum core flux density of 1.2 T. The study thoroughly examines the fundamental aspects related to the design of gapped-core shunt reactors. An optimal design is achieved by determining the optimal ratio of the cross-sectional area to the height of each core disk, employing a MATLAB code to minimize the reactor's initial manufacturing cost (IC) or losses. In addition, the proposed design undergoes simulation and analysis using the finite element method (FEM) in the MAXWELL software. The reactor's inductance is obtained through both Maxwell three-dimensional (3D) simulation and analytical methods, demonstrating a reasonable agreement that validates the effectiveness and reliability of the proposed approach.

Compact two-port antenna with high isolation based on the defected ground for THz communication

The two-port antenna is designed for THz communication where isolation is achieved with the defective ground. The radiator of the two-port antenna is inspired by the half-cutting technology which reduces the size and makes it a compact antenna. The T-shaped stub and open-ended slot are used to modify the capacitive and inductive reactance which diminish and discontinued the surface current to improve the port isolation. The T-shaped stub improves the electric length of the ground and enhances the port isolation by up to 3.4 dB and open-ended slot in the ground is used to weaken the mutual current and create the non-uniform current which intensifications the port isolation up to 7.7 dB at 2.2 THz. The dimensions of the design is 100 µm × 105 µm and the edge distance of the antennas is only 0.20λ with maximum isolation is 30 dB at 2.2 THz. The bandwidth of the two-port antenna is 1.74 THz to 2.52 THz that can be applicable in wireless communication applications.

Appropriate Sodium Bicarbonate Concentration Enhances the Intracellular Water Metabolism, Nutrient Transport and Photosynthesis Capacities of Coix lacryma-jobi L.

Karst ecological stresses are harmful to plant growth, especially high bicarbonate concentrations, drought, high pH, etc. In this study, the effects of 0, 2.0, 7.0 and 12.0 mmol L−1 sodium bicarbonate concentrations on the biomass, electrophysiological properties, intracellular water metabolism, nutrient transport, photosynthesis and chlorophyll fluorescence of Coix lacryma-jobi L. were investigated. The results show that 2.0 mmol L−1 sodium bicarbonate effectively improved the biomass formation of Coix lacryma-jobi L., notably increased its intrinsic capacitance (IC) and decreased its intrinsic resistance (IR), intrinsic impedance (IZ), intrinsic capacitive reactance (IXc) and intrinsic inductive reactance (IXL) as well as reliably enhanced its intracellular water metabolism, nutrient transport and photosynthetic capacities. However, 7.0 and 12.0 mmol L−1 sodium bicarbonate concentrations exhibited marked inhibitory effects on the plants’ photosynthetic rate, stomatal conductance, transpiration rate and dry weight, whereas they did not significantly change the intracellular water metabolism or the nutrient transport capacity of Coix lacryma-jobi L. This study highlights that appropriate bicarbonate levels could enhance the intracellular water metabolism, nutrient transport, photosynthesis and growth of Coix lacryma-jobi L., which can be rapidly monitored by the plant’s electrophysiological properties. Importantly, plant electrophysiological measurement is significantly superior to photosynthesis measurement. In the future, plant electrophysiological measurement can be used as a means to quickly and effectively evaluate the physiological response of plants to the external environment.

Simplified Analysis and Characterization of Dual Power Source Wireless Power Transfer System

Non-contact wireless power transfer systems require power regulation to ensure their proper operation at rated power due to the many degrees of freedom in non-contact coupling structures. Recently, a promising technology has been introduced for wireless power transfer systems, namely, the fractional-order technology with dual power sources to construct an equivalent impedance structure with both variable resistance and reactance. Unlike other impedance matching technologies, the fractional-order technology allows for the adjustment of the equivalent impedance of the resonant network without requiring precise selection of resonant parameters. However, this technology has not been widely adopted due to the abstract concepts involved in fractional calculus theory and control logic. In this study, we employed circuit theory to comprehensively analyze the electrical implications of fractional theory and to provide a detailed description of the inner features of Cα. This study reveals the underlying correlation between control variables and the order of Cα. Additionally, it is shown that the same fractional-order circuit can display both inductive and capacitive reactance, resulting in a significant extension of the impedance adjustment range of fractional-order components. A prototype was designed and constructed to validate the proposed approach, and the experimental results closely matched the theoretical calculations obtained from the proposed approach.

Parasitic Effects in Impedance Spectrum of PEM Water Electrolysis Cells: Case Study of High‐Frequency Inductive Effects

Electrochemical impedance spectroscopy (EIS) is a powerful tool to characterize and distinguish electrochemical, electrical, and diffusive processes in an electrolysis cell. The EIS response with small impedance (mΩ) depends on components and materials of the cell, but often also on the electrical setup, cables, and connectors, leading to incorrect conclusions about the performance of the electrolysis cells. These parasitic effects are assessed via a short‐circuit measurement and confirmed to be external from the membrane electrode assembly (MEA). In the setup, the inductive characteristic is described by a modified inductive reactance and must be included in the equivalent circuit model (ECM) which is fitting the cell EIS spectra in operation (in situ). If points of the spectra showing inductive characteristic (below x‐axis in Nyquist plot) are excluded from the ECM evaluation, an artificially increased ohmic resistance at high frequencies is obtained. In addition, considerations on other components of the ECM can be misleading and significantly incorrect. The only way to avoid that inductive behavior caused by the external setup is incorrectly assigned to the ECM describing properties of the MEA is to include the inductive effects in the ECM analysis of in situ EIS measurements.

Negative Capacitance and Intrinsic Ferroelectric Behavior in α-MoO3 Culminating as a Robust Piezoelectric Energy Harvester

Driven by the notion that the spectrum of ferroelectric applications can be widened and the current subset of materials could be replaced with earth-abundant, lead-free materials, single-phase α-MoO3 (MO) with biaxial van der Waals gap was synthesized, revealing an orthorhombic Pmcn symmetry with a layered ABAB... sequence, with mirrored A and B layers. The force-driven dielectric constant of MO was found to be 12.5 at 0.5 N force level, which showed dielectric saturation behavior with increasing dynamic force. Ferroelectric studies revealed a maximum of 46% efficiency at 10 kV/cm external electric field, and piezoelectric modulus (d33) of 30 pC/N was obtained using the Berlincourt method. Negative capacitance (NC) effects were observed and attributed to the ferroelectric-induced emf and the inductive reactance, in accordance with Lenz’s law. Based on the confluence of the aforementioned features, a piezoelectric energy harvester (PEH) was fabricated, which reached a peak voltage of 4 V under repetitive finger tapping. The power density of the PEH under 100 MΩ resistive load was found to be 7.32 × 10–1 μW/cm2. This enshrines MO as a promising piezoelectric candidate with exotic properties that can be tailored to have multifaceted applications in the realm of sensing and energy harvesting to drive Internet-of-Things and Industry 4.0.

Compact Ultrawideband High-Efficiency Rectifier Using an Exponential Tapered Transmission Line

In this letter, a compact ultrawideband high-efficiency (UWHE) microwave rectifier using an exponential tapered transmission line (ETTL) is proposed. The inductive reactance of the filtering capacitor at the band higher than the self-resonant frequency is used to compensate the capacitive reactance of the diode appropriately. Consequently, the proposed design method can immune to the parasitic impedance of diode as frequency increasing. Meanwhile, an ETTL is adopted for ultrawideband impedance matching at input port. For demonstration, a rectifier prototype is designed, fabricated, and measured. The result shows that the design provides the wide bandwidth of 194% from 0.06 to 3.91 GHz for the power conversion efficiency (PCE) higher than 50% with the input power of 17 dBm. The peak PCE of 68.8% is obtained at 0.915 GHz for the input power of 21 dBm.