Analysis Of AC Research Articles

Role of multivalent state of B-site cations on the electrical transport behavior of Zn-substituted double perovskite: La2CuMnO6

The localization and delocalization of charge carriers considerably affect the ceramic's electrical transport characteristics. These phenomena depend on the cationic charge states, grain growth, crystal geometry, etc. Doping of similar cationic charge states and comparative ionic radii cations are expected to alter the crystal geometry only. In contrast, exciting features are reflected in the results when such substitution affects the cationic valance states. Our previous work reported the structural, electronic, dielectric, and magnetic behavior of Zn-doped La2CuMnO6 (LCM) [1]. A complex coordination state of B-site cations produced tilt in the crystal geometry, diffused relaxor behavior in dielectric response, and non-colinearity in the antiferromagnetic behavior of these oxides. However, the extents of cationic charge states were unraveled. This work reassembles the synergistic role of cationic charge states and their corresponding interactions on the electrical transport behavior of LCM, La2Cu0.5Zn0.5MnO6 (LCZM), and La2ZnMnO6 (LZM). The detailed analysis of AC- and DC- conductivity depicted the shift of long-range dynamics to short-range dynamics with Zn-substitution under the influence of temperature and frequency.

An AC Z-bus-based distribution factors for contingency analysis of AC–DC networks

The AC–DC networks are susceptible to deliberate and unforeseen contingencies, much like any other traditional power network. Due to the complex form of the unified impedance matrix derived for the provided network, the classic Z-bus-based contingency analysis approach cannot comprehend the AC–DC network. The distribution factors thus obtained from a unified complex Z-bus lead to an indication of the flow of complex current for DC lines. Therefore, an alternative method to discover post-contingency consequences is looked for. A streamlined approach for visualizing an equivalent AC network for the given AC–DC network has been proposed in this work. The AC-equivalent network takes the original AC–DC network and recreates it using two parallel AC networks to get the requisite distribution factors. The ultimate current/power distributions of the original AC–DC network can be determined by applying the superposition rule to the parallel networks, by the linear characteristics of the suggested technique. With this, the standard AC-contingency analysis method to complete the steady-state contingency analysis for the AC–DC network can be utilized. The proposed approach has been validated by the encouraging outcomes achieved for AC–DC networks with 10, 13, and 66 buses.

Quantitative analysis of ITER Poloidal Field joints through rigorous resistivity parameterization

The lap-type twin-box joints are integral components in International Thermonuclear Experimental Reactor (ITER) fusion magnets, with profound implications for magnet stability based on their electro-magnetic, thermal, and mechanical properties. Throughout the extensive R&D process, rigorous qualification tests are conducted to meet stringent standards. However, existing tests often prioritize global performance, which lack of strand-level details due to inherent limitations in test setups. Furthermore, as the referencing test facility of SULTAN falls short in replicating relevant ITER operating conditions, numerical methods that offer both accuracy and the requisite level of detail for comprehensive magnet and component analysis and development are necessary. This paper introduces the utilization of the JackPot-AC/DC code, developed at the University of Twente, as a fundamental tool for achieving strand-level precision in handling CICCs and joints, which encompasses copper and solder components. The primary focus of this study is to obtain precise input parameters, emphasizing their role in conducting a quantitative analysis using JackPot-AC/DC. The investigation centers on an ITER PF5 joint (PFJEU6), where contact resistances and AC losses were measured under parallel magnetic fields. Given the constraints in the measured results, an enhanced parameterization is performed to derive precise resistivity and solder-related parameters. Additionally, sensitivity analyses of individual parameters and cable compact configurations are thoughtfully evaluated. With the optimal input parameters acquired, systematic simulations of the joint exposed to transverse magnetic fields, mimicking SULTAN and ITER operating conditions, are processed and validated against experimental results. This research establishes a comprehensive foundation for the analysis of lap-type twin-box joints, including DC, AC, and stability properties. The outcomes will significantly contribute to advancing the understanding of the intricate behavior of these joints in the context of fusion magnet applications.

Combined ultra‐microelectrode: Exploring new potentials for in vivo/in situ ascorbic acid electroanalysis

AbstractMiniaturized and portable analytical tools show promise for sophisticated analysis, particularly in biological systems such as fruits, and they are suitable for advanced agriculture and related food industries. In this study, we developed combined ultra‐microelectrodes (UME) by modifying a microscale carbon fiber electrode (33 μm) coated with an Au nano‐film in a micropipette‐tip system. The proposed UME@Au exhibited a linear response to AC concentrations ranging from 30 to 1400 μM, with a 16 μM limit of detection. It demonstrated the ability to perform in vivo‐in vitro AC analysis in micro‐zones and volumes, such as different points of fruit tissue (Such as lemon) and within the body of a living plant (Such as Cactus arms and trunk), serving as a tiny implanted probe.In the first part of our study, we analyzed AC levels in lemon tissue directly. Our measurements revealed that AC levels are distributed heterogeneously in a single fruit. Additionally, stored AC levels depend on the color of the lemon (yellow ones have higher levels than the green ones). Furthermore, the UME was applied to control AC levels in different storage conditions, including opened containers, airtight containers, with and without exposing daylight, etc.In the second part, the UME@Au was utilized as an implanted sensor for in vivo analysis of AC in different parts of the cactus, recognized as a source of AC. No sample preparation is needed with minimum damage. The implanted microsensor could perform electroanalysis inside the live plant and stored parenchyma cells, etc. Notably, our results showed that AC levels are higher in the younger arms compared to the older ones, and so on.Based on our findings, the miniaturized, small, cheap, user‐friendly electrode demonstrated many capabilities, such as being implantable, having satisfactory stability, and not requiring sample preparations for analysis. It can open up a new window for micro‐electroanalysis in food and analytical plant sciences. We predict that this microscale platform can be modified and used for bioanalysis of other (bio)targets, such as vitamins, ions, and even the detection of plant pathogens in plants and crops directly. This involvement in the smart and modern farming industry is anticipated in the near future.

Design and analysis of solitary AC–AC converter using reduced components for efficient power generation system

Considering different applications that require varied power and voltage conversion levels between AC grids and AC loads, AC–AC power conversion between AC grids has become an inevitable technology of energy management systems. An isolated converter for performing AC-to-AC transmission is proposed with minimal components for reduced losses and enhanced system efficiency. Single-phase direct buck-boost AC to AC converter with minimum components constituted with two dual IGBT control units (IGBT 1–IGBT 4), inductor (Lf), and capacitor (Cf) is proposed in this work. The MATLAB/Simulink platform is used to provide in-depth analysis of the circuit and components along with the design guidelines, and simulation outcomes of this proposed model. The voltage gains of G = 2.13, power factor of 0.97, and overall efficiency of 98% are achieved in the proposed system with minimum components of 4 switches, 2 conductors, and 1 capacitor and inductor respectively. The obtained results are compared with existing technology to evaluate the proposed system.

Comparative Analysis of Various Topologies for AC and DC Power Distribution Systems on Efficiency Grounds

Efficiency is the factor that once wiped DC out of the power system at the birth of electricity, in nineteenth century. The battle of currents between AC and DC has reignited with the aggravating employment of DC in the sectors of generation, transmission, and utilization. This calls for cutting edge research in the field of comparative efficiency analysis of AC and DC, on distribution scale. The current research effort compares AC and DC distribution systems on efficiency grounds, for various topologies. The two systems are compared employing normal distribution technique for residential load profile. The varying efficiency of power electronic converters (PECs) with stochastic load profiles is modeled using MATLAB/SIMULINK, for each topology. DC takes the lead against AC with efficiency advantage for energy efficient load-based architectures. The architectures with variable speed drive-based loads, the efficiency advantage in favor of DC is between 1% and 2%, however, the efficiency advantage reaches to 12% with inherent DC loads. In contrast, AC takes the lead with conventional distribution, with an efficiency advantage between 4% and 5%. The findings of current research work can prove to be beneficial in making policy decisions for the adoption of DC at distribution scale.

Optimal power flow and computer‐based analysis of a simultaneous AC–DC power transmission system

AbstractElectricity demand is constantly increasing with the growing population, and the process of establishing new transmission lines has become complicated due to the rise in industrialization and urbanization. One solution to meeting this increased demand is to improve the power transfer capability by increasing the transmission voltage. However, the existing transmission lines may not be able to handle the increased load if they are pushed to their thermal limit. This paper presents a mathematical analysis of a simultaneous AC–DC transmission system transmitting power at different values of parameters. The computational analysis is carried out using MATLAB, and the circuit model simulation is validated by using power systems computer aided design (PSCAD/EMTDC). The transmitted power is evaluated by varying the transmission angle and transmission length for a fixed voltage, and then by varying the transmission angle and voltage for a fixed transmission length. Both these cases are analyzed using approximate and actual formulas. The results of the computation and simulation show close conformity.

Effects of solvatomorphism, the nature of a chelating ligand synthon and a counterion on the single crystal XRD structure and SMM properties of paramagnetic monocapped cobalt(II) tris-pyrazoloximates.

A series of monocapped cobalt(II) tris-pyrazoloximates was obtained through the template condensation of the corresponding pyrazoloxime, phenylboronic acid and a suitable cobalt(II) halogenide. Comparing 3-acetylpyrazoloxime versus its methine-containing homolog, the former produced cobalt(II) clathrochelates in substantially higher yields due to the electron donating effect of the methyl substituent, increasing the N-donor ability of its oxime group. Their less N-donor analog with the electron acceptor trifluoromethyl group did not form cobalt(II) complexes of this type. In all their solvent-free and solvent-containing crystals, the encapsulated cobalt(II) ion adopted a high-spin state, as gauged by the Co-N bond lengths of 2.112(4)-2.188(9) Å, and was located almost in the center of its CoN6-coordination polyhedron. Their CoN6-polyhedra had an almost ideal trigonal-prismatic (TP) geometry with distortion angles φ below 4°. This TP-like geometry was assisted by hydrogen bonding between their NH groups and the apical counterion. The absence of methyl groups makes them close to an ideal TP. In contrast, stronger N-H⋯Cl hydrogen bonds occurred in the methyl-containing complex, while the Co-N bond lengths stayed the same at 2.144(2) Å on average. In its solvates with benzene, chloroform and acetone, there is a clear tendency for φ to decrease from 2.7(3)° to 0.47(13)°. The comparable effects of the ribbed methyl substituents, the cross-linking counterion and the lattice solvent on their molecular geometry were observed; the larger the distortions from an ideal TP geometry, the stronger the hydrogen bonds to the corresponding apical halogenide anion. The analysis of the experimental AC- and DC-magnetometry data for their fine-crystalline samples suggests that the passing from the derivative of the methyl-substituted synthon to that of its methine-containing homolog caused a substantial decrease in the magnetic susceptibility value χT and an increase in the QTM contribution to the magnetic relaxation. The effect of a cross-linking halogenide counteranion on the Orbach remagnetization barrier is greater than that of the solvatomorphism of their crystals.

Comparative analysis of electric motor drives employed for propulsion purpose of Battery Electric Vehicle (BEV) systems

This paper presents an analysis of electric motor drives for the propulsion system of a battery electric vehicle (BEV). It offers a comprehensive review and mathematical analysis of both AC and DC motor drives commonly used in electric vehicle (EV) applications. Various types of electric motor drives have been utilized for EV propulsion, and among them, the Permanent Magnet Synchronous Motor (PMSM) drive stands out as the optimal choice. The PMSM drive demonstrates superior performance and numerous advantages, including a robust structure, high efficiency, compact size, reduced maintenance costs, and minimal torque ripple. These characteristics make it a more suitable option for EV propulsion compared to other motors. This study investigates the performance of the PMSM drive in comparison to other competitive electric motor drives used in EV propulsion systems, namely the Brushless DC Motor (BLDCM), the Induction Motor (IM), and the Switched Reluctance Motor (SRM). The evaluation focuses on key criteria for electric motors—output power and torque densities, essential for effective application in EV propulsion systems. The paper introduces novel mathematical and analytical relationships between two prominent PM motor families: the PMSM and the BLDCM. Both motors are highly competitive in terms of power and torque output. The mathematical analysis and graphical plot simulation results demonstrate that the PMSM drive offers the highest power and torque densities among the three motor drives. Specifically, the PMSM drive exhibits 29.90% greater power and torque densities than the BLDCM drive, 88.68% greater than the SRM drive, and an impressive 200% greater than the IM drive, all under the same operating parameters such as power factor, size, rating, and efficiency. These findings highlight the significant advantages of the PMSM drive, positioning it as a superior choice for electric vehicle propulsion systems.

Organic Solar Cells: An Analysis of AC and DC Electrical Properties

In this paper, AC and DC electrical properties of organic solar cells based on P3HT:PCBM active layer have been investigated. The performance of such solar cell has demonstrated the efficiency of 2.31% corresponding with short-circuit current density of 6.08 mA ⋅ cm[Formula: see text], open circuit voltage of 0.64 V and fill factor of 60%. The equivalent circuit and the properties of the supposed interfaces between the layers in the P3HT:PCBM-based solar cell have been estimated. AC properties have demonstrated series capacitance increasing with increasing frequencies, which means series capacitance saves charges and parallel capacitance has decreased with increasing of frequency work as discharge part of charges stored in series capacitance. Also, equivalent series and parallel resistances have demonstrated a decrease from 7 [Formula: see text] and 120 k[Formula: see text] at low frequency to 1 [Formula: see text] and 43 k[Formula: see text] at high frequencies, respectively.

Facile synthesis of microwave-etched Ti3C2 MXene/activated carbon hybrid for lithium-ion battery anode

In this study, we synthesized MXene hybrid electrodes using a novel strategy to generate a synergistic effect between the respective components. Initially, a few-layered Ti3C2 MXene was prepared via microwave-assisted in-situ etching. The AC to Ti3C2 MXene ratio is varied to be 10:0, 9:1, 8:2, and 7:3 in order to maximize electrochemical efficiency. As an anode material for LIBs, the hybrid AC_Ti3C2 (8:2) electrode exhibits the highest initial specific capacity of 1194.2 mAh/g discharged at a current density of 0.2 A/g and maintains over 841.8 mAh/g after 80 consecutive cycles (with a Coulombic efficiency of ∼100 %). An increase in the discharge capacity of the hybrid electrode from 750.5 to 881.9 mAh/g when the current density changed from 1 to 0.2 A/g suggests the excellent rate capability of the AC_Ti3C2 (8:2) hybrid electrode. Furthermore, electrochemical impedance spectroscopic analysis of AC_Ti3C2 (8:2) shows a low charge transfer resistance (Rct) of 8.52 Ω, indicating good conductivity of the hybrid electrode. The work presented here confirms that the AC can be used as an interlayer spacer in synthesizing Ti3C2 MXene hybrids and have excellent application prospects for the next-generation LIBs.

Comparative Efficiency and Sensitivity Analysis of AC and DC Power Distribution Paradigms for Residential Localities

The new millennium has witnessed a pervasive shift of trend from AC to DC in the residential load sector. The shift is predominantly due to independent residential solar PV systems at rooftops and escalating electronic loads with better energy saving potential integrated with diminishing prices as well as commercial availability of DC-based appliances. Comprehensive sensitivity analysis considering the real load profile is missing in the present body of knowledge. In order to fill that gap, this paper is an attempt to include a comprehensive sensitivity analysis of the DC distribution system and its simulation-based comparison with its AC counterpart, considering the real load profile. The paper uses the Monte Carlo technique and probabilistic approach to add diversity in residential loads consumption to obtain an instantaneous load profile. Various possible scenarios such as variation of standard deviation from 5% to 20% of mean load value, PV capacity variation from 1000 W to 9000 W, and variation in power electronic converter (PEC) efficiencies are incorporated to make the system realistic as much as possible maintaining a fair comparison between both systems. The paper concludes with the baseline efficiency advantage of 2% to 3% during the day for the case of the DC distribution system as compared to the AC distribution system.

Analysis of a new SEPIC AC–DC PFC converter for light emitting diode applications

Active power factor correction (PFC) converters are used to increase the power factor and improve the total harmonic distortion as a result of reducing the harmonics in the current. In this paper, a new bridgeless single-ended primary inductor converter (SEPIC) topology used in light emitting diode (LED) load is proposed to obtain near-unity power factor. By eliminating the input bridge in the bridge PFC converter, the total harmonics distortion is improved and a lower cost is obtained. The reactive power control is used to generate the reference current signal in the proposed converter to control the LED current. To demonstrate the applicability of the proposed topology and to compare its performance with the bridge SEPIC topology, PSIM circuit simulation was used, and an experimental prototype was performed. In the experimental study, 25 Vrms input voltage was applied, and 10 V DC voltage was obtained at the output. Using the proposed converter, the total harmonic distortion value was reduced from 5.722% to 1.837%, and the power factor was increased to 0.999. The experimental and simulation results showed that the total harmonic distortion value of the input current improved and that the proposed SEPIC PFC converter for low-power circuits, particularly in LED applications, is a very good option.

Power flow analysis of hybrid AC/DC microgrid based on power electronic transformer

Power flow analysis is the basis for planning, design and optimized operation of Hybrid AC/DC microgrids. Aiming at the impact of the introduction of power electronic transformers on the power flow distribution of the Hybrid AC/DC microgrid, this paper will carry out the power flow analysis of the Hybrid AC/DC microgrid based on the power electronic transformer. First, the topology of the Hybrid AC/DC microgrid based on power electronic transformer is proposed, and the configuration of the source, load, and storage of the microgrid is given. Next, an equivalent model for power flow analysis of Hybrid AC/DC microgrid is established in Simulink. Finally, the power flow analysis of AC and DC hybrid microgrid with and without power electronic transformers is carried out respectively. The simulation results show that the power electronic transformer can make the Hybrid AC/DC microgrid fully consume new energy, and effectively realize the optimized and coordinated operation of source, grid, load, and storage.

Harmonic analysis of AC drive double PWM back to back network side

Aiming at the problem of harmonic pollution in the control system of large-scale steel rolling equipment in metallurgical plant, the mechanism of harmonic generation in AC-AC frequency conversion and AC-DC-AC variable-frequency speed regulation system is analyzed, and a double PWM back-to-back AC speed regulation system is proposed. This system can not only realize the regeneration energy of frequency converter, but also reduce the harmonic wave, and greatly improve the power factor of the system. Finally, through MATLAB simulation, the harmonic of AC-AC frequency conversion and AC-DC-AC variable-frequency speed regulation system is analyzed, and compared with PWM back-to-back AC speed regulation system, the superiority, effectiveness and feasibility of PWM back-to-back AC speed regulation system design for large-scale AC drive device control are proved.

Multi Step Transient Hybrid Simulation Framework Design and Practical Engineering Application for AC / DC Power Grid

Based on the large power grid simulation and the existing security prevention and control mode, this paper further integrates the multi-step transient hybrid simulation architecture computing technology to research the high-performance analysis and situational awareness simulation technology of interconnected AC / DC large power grid security and stability characteristics. So as to realize the “panoramic situational awareness, wide area coordinated control, flexible and efficient service” of large power grid, and improve the super large scale power grid Comprehensive security defense and intelligent monitoring level of panoramic, multi-dimensional and three-dimensional.

Comparative Analysis of AC and DC Distribution System with Respect to Harmonic Distortion Considering Daily Load Profile

Electrical energy is the most efficient and the cleanest form of energy at the moment that is being transmitted and distributed amongst end-users. From its earlier days, the AC system was preferred as an economical solution for transmission and distribution. However, the development in the power electronics technology and the evolution of highly efficient power electronic converters have established the resurgence of DC power system. Furthermore, the trend is shifting towards DC loads as various energy efficient appliances, such as DC inverter air conditioners, operate on DC nowadays. This further advocates the shift towards the DC power system. This research works is an effort to perform the comparative analysis of AC Distribution System (ACDS) and DC Distribution System (DCDS), with regards to power quality and harmonic distortion in particular. The comparison is performed considering load profile and load variation on daily basis. Simulations are performed in MATLAB. It has been concluded at the end that ACDS is better than DCDS in terms of power quality as total harmonic distortion of the DCDS under the same loading and same load variation during the whole day was significantly higher than that of ACDS.

A Magneto Dielectric AC Measuring Transducer for Refinery Automation Systems

The aim of this research is theoretical analysis and mathematical modeling of AC measuring transducers based on magnetodielectric cores for automation systems of oil refineries. An analytical study of the magnetization curve is carried out, an equivalent circuit is constructed, and a mathematical transducer model on its basis is obtained. A numerical study of the proposed transducer is carried out.

Ageing state identification and analysis of AC 500 kV XLPE submarine cable based on high‐voltage frequency dielectric response

Carrying out the insulation condition measurement and analysis is important for the safe operation of the submarine cable. In this study, the high-voltage frequency dielectric response is used to identify the ageing state of the AC 500 kV cross-linked polyethylene (XLPE) submarine cable. The complex capacitance and tanδ in the low-frequency area for the new, thermal ageing, electro-thermal ageing cable all increase with the testing voltage increased from 200 to 2000 V. It is founded that the dielectric response at high voltage is more likely to detect the ageing differences. Based on the carbonyl index and the dielectric loss of the XLPE specimens at different position of the insulation layer, the non-uniform ageing phenomenon of the cable insulation is presented for the thermal ageing and electro-thermal ageing cable. The loss quantity parameter and its changing behaviour with testing voltage based on the frequency dielectric response could be used to identify the ageing state. The comparison of the modified Cole–Cole model parameter under 200 and 2000 V also indicates that the higher voltage dielectric response is helpful to identify the ageing differences.

Magnetic relaxation process determination in the Co/Au nanoparticle system

Nonequilibrium magnetic dynamics has been investigated in the Co/Au bimetallic nanoparticle system. The system exhibits typical superparamagnetic behavior at higher temperatures and unequivocal hallmarks of magnetic relaxation process at $T\ensuremath{\sim}7\phantom{\rule{0.28em}{0ex}}\mathrm{K}$. Since different scenarios of magnetic transition can be hypothesized here, detailed analysis of magnetization ac and dc experimental data has been performed. Specific methods have been employed in order to reveal the nature of the examined process. The observation of critical dynamics [power-law divergence of the relaxation time at ${T}_{g}$; dynamic scaling of ${\ensuremath{\chi}}^{\ensuremath{'}\ensuremath{'}}(T,f)$ data] and aging effects in the presence of strong interparticle interactions provide evidence that the system undergoes a transition to a super-spin-glass state rather than to a super-spin-blocked state.