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This paper presents power quality issues, and ways to resolve these problems. There are a number of custom power devices which are used to resolve these issues. The Dynamic Voltage Restorer (DVR) is a special device that is used nowadays. To detect the voltage drop system, park transform is utilized and applied to the voltage regulator as a control system function, that detects the voltage amplitude at the sensitive load constantly in DVR (using a three-phase voltage source inverter with voltage loop control (PI)) (Martiningsih & Prakoso, 2018). This paper is about basic working of DVR with simulation results. MATLAB is used in this work, and confirmed the convincingness of the DVR. [ABSTRACT FROM AUTHOR]

Aiming at the solid oxide fuel cell (SOFC) applied to the ship DC microgrid in the face of pulse load disturbance is prone to make the SOFC voltage drop too large leading to the DC grid oscillation problem. In this paper, a stability criterion method for SOFC-Li battery DC system based on hybrid potential function is proposed. Firstly, a mathematical model of shipboard DC microgrid with SOFC-Li battery is established and the accuracy of the model is verified. Then, the stability criterion of the system based on the hybrid potential function under large disturbances is constructed. Subsequently, the effects of system stability under impulse load conditions were analysed under different parameters. Based on the constructed criterion, simulation verification of the stability boundary conditions of the SOFC system operating independently or jointly with a lithium battery system is carried out. The experimental results show that the proposed stability criterion and control strategy are effective in accurately predicting the system stability boundary. The experimental results verify the effectiveness of the proposed method in improving the stability of the system and provide a theoretical basis for further research on the dynamic characteristics of SOFC systems under complex load conditions. [ABSTRACT FROM AUTHOR]

This paper is concerned with a linear theory of thermopiezoelectricity in which the second gradient of the displacement, the second gradient of the electric potential and the second temperature gradient are included in the classic set of independent constitutive variables. The present paper is based on Green–Naghdi thermomechanics. The introduction of the entropy flux tensor leads to constitutive equations that depend on the second temperature gradient. The fundamental boundary-initial-value problems are formulated and the uniqueness of the solution is studied. Two applications of the theory are presented. We study the problem of a concentrated charge density acting in an unbounded region, as well as the effects of a concentrated heat source. [ABSTRACT FROM AUTHOR]

Voltage source converter based high voltage direct current (VSC-HVDC) can participate in voltage regulation by flexible control to help maintain the voltage stability of the power grid. In order to quantitatively evaluate its influence on the voltage interaction between VSC-HVDC and line commutated converter based high voltage direct current (LCC-HVDC), this paper proposes a hybrid multi-infeed interaction factor (HMIIF) calculation method considering the voltage regulation control characteristics of VSC-HVDC. Firstly, for a hybrid multi-infeed high voltage direct current system, an additional equivalent operating admittance matrix is constructed to characterize HVDC equipment characteristics under small disturbance. Secondly, based on the characteristic curve between the reactive power and the voltage of a certain VSC-HVDC project, the additional equivalent operating admittance of VSC-HVDC is derived. The additional equivalent operating admittance matrix calculation method is proposed. Thirdly, the equivalent bus impedance matrix is obtained by modifying the alternating current (AC) system admittance matrix with the additional equivalent operating admittance matrix. On this basis, the HMIIF calculation method based on the equivalent bus impedance ratio is proposed. Finally, the effectiveness of the proposed method is verified in a hybrid dual-infeed high voltage direct current system constructed in Power Systems Computer Aided Design (PSCAD), and the influence of voltage regulation control on HMIIF is analyzed. [ABSTRACT FROM AUTHOR]

Data products relating to auroral arc systems are often sparse and distributed while ionospheric simulations generally require spatially continuous maps as boundary conditions at the topside ionosphere. Fortunately, all‐sky auroral imagery can provide information to fill in the gaps. This paper describes three methods for creating electrostatic plasma convection maps from multi‐spectral imagery combined with plasma flow data tracks from heterogeneous sources. These methods are tailored to discrete arc structures with coherent morphologies. The first method, "reconstruction," builds the electric potential map (from which the flow field is derived) out of numerous arc‐like ridges that are then optimized against the plasma flow data. This method is designed for data from localized swarms of spacecraft distributed in both latitude and longitude. The second method, "replication," uses a 1D across‐arc flow data track and replicates these data along a determined primary and secondary arc boundary while simultaneously scaling and rotating to keep the flow direction parallel to the arc and the flow shear localized at the arc boundaries. The third, "weighted replication," performs a replication on two data tracks and calculates a weighted average between them, where the weighting is based on data track proximity. This paper shows the use of these boundary conditions in driving and assessing 3D auroral ionospheric, multi‐fluid simulations. Plain Language Summary: The aurora, or northern and southern lights, are embedded within a complicated system of interacting electric fields, magnetic fields, and charged particles, the more energetic of which produce the lights themselves by exciting the neutral atmosphere. This brings about a 3D electric current system. These currents enter and exit the atmosphere along the Earth's magnetic field lines, and can only close their circuit between 80 and 150 km. This paper outlines the importance of simulating auroral arc systems in 3D and thus the need for generating continuous horizontal top‐boundary drivers for these simulations. This is difficult as the available data products are limited. This paper provides three methods for creating these boundary conditions using multi‐color, all‐sky auroral imagery in conjunction with approximately across‐arc plasma flow data tracks provided by spacecraft, sounding rockets, and/or radar measurements. Key Points: We provide three methods for developing ionospheric convection flow maps from limited data tracks in conjunction with auroral imageryMethods for generating distributed plasma flow surrounding auroral arcs can benefit from auroral arc information provided by all‐sky imageryModeling realistic auroral current closure needs drivers that vary along‐arc, across‐arc, and in altitude via electron precipitation spectra [ABSTRACT FROM AUTHOR]

The paper presents summary data based on the results of laboratory studies and comprehensive industrial trials of a fundamentally new type of product in electrometallurgy — cores of graphitized electrodes developed at PWI of the NAS of Ukraine for DC and AC arc steel-melting furnaces of up to 50 t capacity. It is shown that during the last decades, the world production of steel has increased continuously, getting very close to 2 bln t per year. Approximately 30 % of this volume is produced in arc furnaces, and by the end of this decade it will reach 40 %. It is shown that the cored electrode arc has much lower specific current and power values in all the sections (cathode, column, anode) than the monolithic electrode arc. It was found that voltage drop in the core cathode spot is 2.3‒3.3 times smaller than in the monolithic electrode. Cored electrodes improve all the technical-economic characteristics of operation of DC and AC steel-melting furnaces. [ABSTRACT FROM AUTHOR]

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Pyroelectric materials, with piezoelectricity and pyroelectricity, have been widely used in infrared thermal detectors. In this paper, a modified first-order plate theory is extended to analyze a pyroelectric sensitive element structure. The displacement, temperature, and electric potential expand along the thickness direction. The governing equation of the pyroelectric plate is built up. The potential distributions with upper and lower electrodes are obtained under different supported boundary conditions. The corresponding numerical results of electric potential are consistent with those obtained by the three-dimensional finite element method. Meanwhile, the theoretical results of electric potential are close to that of experiments. The influence of supported boundary conditions, piezoelectric effect, and plate thickness are analyzed. Numerical results show that the piezoelectric effect reduces the electric potential. The thickness of the pyroelectric plate enhances the electric potential but reduces the response speed of the detector. It is anticipated that the pyroelectric plate theory can provide a theoretical approach for the structural design of pyroelectric sensitive elements. [ABSTRACT FROM AUTHOR]

During the modulation process of the VSI motor drive system, the nonlinear errors caused by the dead-time and conduction voltage drop will increase the phase current harmonic distortion and the torque ripple. To solve this problem, a novel dead-time free modulation scheme is proposed in this paper. In the non-zero crossing region of the phase current, the switching tube, whose body diode can provide a continuation path, is set as off-state, the driving signal is only implemented on another switching tube with the same bridge arm, and the errors caused by the conduction voltage drop and switching delay are compensated to the pulse duration. At the same time, to suppress the zero current clamp effect that exists near the zero crossing point of the phase current, another modulation scheme for the phase current crossing zero in advance is proposed, which avoids the complicated determination and calculation of the current polarity near the zero crossing point of the current. Both of the above modulation schemes eliminate the dead-time, and the switching principle is presented. In addition, to suppress the impact of the current ripple and high-frequency noise on the accuracy of the phase current detection, a second-order resonance digital filter without phase shift is introduced. Finally, compared to two deadtime compensation methods, the effectiveness and superiority of the proposed dead-time free modulation scheme are verified by the experimental results. [ABSTRACT FROM AUTHOR]

This paper provides a variational treatment of the effect of external charges on the free charges in an infinite free-standing graphene sheet within the Thomas–Fermi theory. We establish existence, uniqueness and regularity of the energy minimizers corresponding to the free charge densities that screen the effect of an external electrostatic potential at the neutrality point. For the potential due to one or several off-layer point charges, we also prove positivity and a precise universal asymptotic decay rate for the screening charge density, as well as an exact charge cancellation by the graphene sheet. We also treat a simpler case of the non-zero background charge density and establish similar results in that case. [ABSTRACT FROM AUTHOR]

In this paper, the effect of doping and nanostructuring on the electrostatic potential across the electrochemical interface between a transition metal oxide and a water electrolyte is investigated by means of the Poisson–Boltzmann model. For spherical nanoparticles and nanorods, compact expressions for the limiting potentials at which the space charge layer includes the whole semiconductor are reported. We provide a quantitative analysis of the distribution of the potential drop between the solid and the liquid and show that the relative importance changes with doping. It is usually assumed that high doping improves charge dynamics in the semiconductor but reduces the width of the space charge layer. However, nanostructuring counterbalances the latter negative effect; we show quantitatively that in highly doped nanoparticles the space charge layer can occupy a similar volume fraction as in low-doped microparticles. Moreover, as shown by some recent experiments, under conditions of high doping the electric fields in the Helmholtz layer can be as high as 100 mV/Å, comparable to electric fields inducing freezing in water. This work provides a systematic quantitative framework for understanding the effects of doping and nanostructuring on electrochemical interfaces, and suggests that it is necessary to better characterize the interface at the atomistic level. [ABSTRACT FROM AUTHOR]

A fast-switching low-loss field-stop insulated gate bipolar transistor with a dual control gate (DIGBT) of a semi-insulating polycrytalline silicon (SIPOS) material is proposed in this paper. Because the SIPOS has uniform high resistance, it has an approximate linear electric potential distribution. When DIGBT conducts, the higher electric potential on SIPOS causes the P-type drift region (P-drift) to generate an inversion layer of electrons, adjusting the number of carriers and making the generation of non-equilibrium carriers no longer dependent on the doping concentration in P-drift (Nd) but on the electric potential distribution on SIPOS. Therefore, it can solve the contradiction among the breakdown voltage, forward voltage drop [VCE(sat)], turn-off time (toff), and turn-off loss (Eoff) caused by the Nd. Through Technology Computer Aided Design (TCAD) simulation, the VCE(sat) of DIGBT is 30.6% lower than that of SJFS IGBT. Meanwhile, DIGBT reduces the toff by 62.8% while reducing the Eoff by 83.0% compared to SJFS IGBT. In addition, the static latch-up I–V and the forward biased safe operating area of the DIGBT have been significantly improved. This paper adjusts the number of carriers through the characteristics of SIPOS material, enabling the above-mentioned physical phenomena to be applied in insulated gate bipolar transistor power devices and achieving device performance breakthroughs. [ABSTRACT FROM AUTHOR]

This paper presents a novel, state-of-the-art predictive control architecture that addresses the computational complexity and limitations of conventional predictive control methodologies while enhancing the performance efficacy of predictive control techniques applied to three-level voltage source converters (NPC inverters). This framework's main goal is to decrease the number of filtered voltage lifespan vectors in each sector, which will increase the overall efficiency of the control system and allow for common mode voltage reduction in three-level voltage source converters. Two particular tactics are described in order to accomplish this. First, a statistical approach is presented for the proactive detection of potential voltage vectors, with an emphasis on selecting and including the vectors that are most frequently used. This method lowers the computational load by limiting the search space needed to find the best voltage vectors. Then, using statistical analysis, a plan is presented to split the sectors into two separate parts, so greatly limiting the number of voltage vectors. The goal of this improved predictive control methodology is to reduce computing demands and mitigate common mode voltage. The suggested strategy's resilience is confirmed in a range of operational scenarios using simulations and empirical evaluation. The findings indicate a pronounced enhancement in computational efficiency and a notable diminution in common mode voltage, thereby underscoring the efficacy of the proposed methodology. This increases their ability to incorporate renewable energy sources into the electrical grid. [ABSTRACT FROM AUTHOR]

This paper aims to analyze the inrush load current and develop an inrush current suppressor circuit optimized for a low-voltage DC (LVDC) distribution network. The connection of a substantial input capacitor in the DC load can induce a surge current, leading to significant issues in the LVDC distribution network, such as DC bus voltage drop and potential system damage. To address this issue, this paper presents the design of a voltage control system for a triple-active-bridge (TAB) converter in the LVDC distribution network, evaluating the need for the inrush current suppressor circuit. Control stability during the occurrence of the inrush current is analyzed using the small-signal model of the TAB converter. In addition, this paper proposes an inrush current suppressor circuit, presenting a design methodology to achieve the desired current suppression performance. Experiments are conducted on a laboratory-scale LVDC distribution network utilizing a 4-kW prototype converter to validate the performance of the suggested inrush current suppressor. [ABSTRACT FROM AUTHOR]

The paper deals with the non-destructive experimental testing of the reinforced concrete beams under progressive corrosion. A series of experiments using electrical potential, ultrasound and low-frequency vibrations techniques are reported. Electrical potential and natural frequencies were used to characterise and monitor the corrosion process at its initial state. The P-wave velocity measurements were proved to be effective in quantitative assessment of the level of corrosion as it progresses. The possibility of early detection of damage using a proposed damage index and diagnostic framework is promising for possible applications in the non-invasive diagnostics of reinforced concrete elements. [ABSTRACT FROM AUTHOR]

This paper introduces a new algorithm designed to address the challenge of distribution network reconfiguration, employing the tabu search metaheuristic in conjunction with the voltage drop concept. Distinguishing itself from existing methods, our proposed approach not only utilizes voltage drop for obtaining the initial solution but also introduces a novel technique for generating a candidate solution neighborhood. This method leverages both randomness and voltage drop, ensuring a smooth and steady descent during algorithm execution. The primary goal of our algorithm is to minimize active power losses within distribution networks. To validate its effectiveness, the proposed method underwent testing on three commonly referenced distribution systems: the 33-Bus, 69-Bus, and 94-Bus systems, widely acknowledged in the literature. A pivotal aspect of our work involves the synergy of the tabu search algorithm with a combination of both random and deterministic methods for generating neighbors. This strategic amalgamation plays a crucial role, enabling rapid execution while consistently yielding high-quality solutions. Additionally, the adoption of the electric distance method for generating the initial solution adds significant value, offering a commendable solution with minimal computational effort. Comparative assessments against other algorithms documented in the literature underscore the superior efficiency of our proposed algorithm. [ABSTRACT FROM AUTHOR]

A kind of material, microencapsulated electronic ink, was prepared and supported on ITO glass used as backplane electrode and etched panels of the words "N-P-U" as pixel electrode. In addition, a quasi-dynamic display device was designed for electronic paper. The control signal generated by monostable process of 555 counter was used to drive the relay to work. The actual output of this kind of display was also observed. Through the combination of 555 counter and relay, quasi-dynamic electronic ink display was able to be achieved at the voltage of 15V. Furthermore, the delay time can be controlled within 0-10 seconds by adjusting monostable trigger time of the counter. [ABSTRACT FROM AUTHOR]

An increasing need for fast and reliable models has led to a continuous development of Fourier-based (FB) analytical modeling. This paper presents an overview of the techniques that are currently available in FB modeling for electric machines. By coupling that overview to the most relevant literature related to the subject, an interesting starting point is provided for anyone who wants to use or improve FB models. The following seven aspects of FB models are discussed in detail: 1) the magnetic potential (scalar or vector potential); 2) the coordinate system and the solution of the partial-differential equations for each magnetic potential and for each coordinate system; 3) the way in which time dependence is accounted for; 4) the implementation of the source terms; 5) the possibilities to account for slotted structures; 6) the modeling of eccentricity; and 7) the post-processing computation of physical quantities, such as flux density, electromotive force, torque, losses, and eddy currents in conductive objects. Furthermore, this paper gives the closed form solution of the Laplace, Poisson, and Helmholtz equations in each coordinate system. In addition, this paper tackles other important features of FB models such as computational time reduction and coupling the machine model to an electric circuit. [ABSTRACT FROM AUTHOR]

In this paper, a new hybrid stator fabrication with 2-D steel sheets lamination and 3-D end cap structure for high-speed motor application is provided. With the additional overhead end cap design, the new motor not only features lower iron losses in high frequency and reduces copper losses like traditional soft magnetic composite (SMC) motor but also achieves higher permeability and lower production cost at the same time. In this paper, the motor characteristics, i.e., back electromotive force and efficiency between the traditional lamination, SMC, and the new hybrid design are investigated by 3-D FEA simulation. Moreover, a prototype is fabricated by 3-D printing for the verification of the analytical and simulation results. [ABSTRACT FROM AUTHOR]

Dynamic response of molecular reorientation near the alignment surface of bistable cholesteric liquid crystal devices was observed by means of the total reflection ellipsometry. From the experimental results, the deviation from the original switching voltage to which the image sticking problem has a close relationship was confirmed, and the cause of the image sticking problem was considered from the viewpoint of the surface energy and Helfrich-type modulation. Especially when the surface free energy is low, director near the alignment surface seems to be distorted by disclinations and Helfrich-type modulation. [ABSTRACT FROM AUTHOR]

Abstract: In this article, existing technologies of switchable liquid crystal gratings and their limitations are discussed. A new mode ferroelectric liquid crystal with its unique characteristics is presented, which shows great potential for grating use. Some possible fabrication procedures and results are also presented in this paper. [ABSTRACT FROM AUTHOR]

A novel microfluidic device containing a bi-gap electrode pair is presented in this paper, and it is capable of continuously separating three different populations of particles using dielectrophoresis. A mixture of 5, 10, and 20 μm polystyrene particles is focused by a sheath flow and then separated based on size after flowing over a bi-gap electrode pair. A new solver is developed in OpenFOAM to investigate the effects of various parameters such as the flow rate, gaps, and electrode pair angles to achieve an appropriate configuration of the bi-gap electrode pair for efficient particle separation. Based on the numerical simulation results, three different configurations of bi-gap electrode pairs are fabricated. The paths of three populations of polystyrene particles under various operating conditions are experimentally examined and compared with numerical results. Then, by examining the purity of the separated particles with three different electrode configurations at different flow rates, the performance of the device is experimentally investigated. The results showed that by employing the proposed electrode configuration, at a maximum flow rate of 100 μL h−1 (25 μL h−1 for the sample), particles are separated precisely (with more than 99% purity for all particles at desired outlets) using a 20 Vpp sinusoidal electric potential with a frequency of 100 kHz. This novel microfluidic device is thus a practical device for continuously separating three different populations of particles/cells according to size in a heterogeneous admixture. [ABSTRACT FROM AUTHOR]

Describes the above-named upcoming special issue or section. May include topics to be covered or calls for papers. [ABSTRACT FROM PUBLISHER]

Phase angle measurements from synchrophasors show discontinuities when they roll over from +180 to -180 degrees or vice versa. This paper proposes efficient strategies for unwrapping of the angles in real-time data streams. Examples presented in this paper first show that the phase angle differences across bus voltage phasors can go over 360 degrees in a synchronized power system under stressed conditions. Unwrapped phase angles are shown to be useful in fast reliable islanding detection methodology, and for phase angle arithmetic such as for averaging of phase angles and for phase angle difference calculations. Strategies for handling missing phase angle data in real-time data streams are also discussed. [ABSTRACT FROM PUBLISHER]

When an alternating voltage is applied to a dielectric material, dipoles in the material try to align in the direction of the applied voltages and polarization process starts. For multi-dielectric media especially in which a liquid interface is involved, such as oilpaper insulation, interfacial polarization is predominantly active among all polarization processes. This interfacial polarization is a very slow process and is effective in lower frequency range. This interfacial polarization reflects the inherent condition of the oilpaper insulation. Due to this reason, frequency domain spectroscopy is performed in lower frequency range to assess the condition of oil-paper insulation. So, the time required for frequency response measurement using conventional frequency domain spectroscopy is quite long. Considering the aforesaid facts, a different procedure has been taken here to measure the dielectric response in a significantly lesser time keeping the entire frequency range of conventional frequency domain spectroscopy. Instead of using pure sinusoidal excitation voltages over wide frequency range, dielectric response current has been measured using excitation having time growing frequency sweep (TGFS) signal. For this purpose, test samples that emulate the oil-paper insulation of real-life transformer have been prepared in the laboratory. The moisture contents of the test samples have been kept different to investigate the reliability of the proposed method. A setup has been made in the laboratory to measure dielectric response currents using the both excitations. In order to investigate the applicability of the proposed method, experiment has also been performed on actual transformers. It has been observed that the use of excitation signal having time growing frequency sweep provides almost similar information regarding insulation condition as obtained by the use of conventional sinusoidal excitation voltages. Hence, the proposed method is capable of reduction in time in FDS nearly by an amount of 85%. [ABSTRACT FROM PUBLISHER]

The excitation energy transfer (EET) process for photosynthetic antenna complexes consisting of subunits, each comprised of multiple chromophores, remains challenging to describe. The multichromophoric Förster resonance energy transfer theory is a popular method to describe the EET process in such systems. This paper presents a new time-domain method for calculating energy transfer based on the combination of multichromophoric Förster resonance energy transfer theory and the Numerical Integration of the Schrödinger Equation method. After validating the method on simple model systems, we apply it to the Light-Harvesting antenna 2 (LH2) complex, a light harvesting antenna found in purple bacteria. We use a simple model combining the overdamped Brownian oscillators to describe the dynamic disorder originating from the environmental fluctuations and the transition charge from the electrostatic potential coupling model to determine the interactions between chromophores. We demonstrate that with this model, both the calculated spectra and the EET rates between the two rings within the LH2 complex agree well with experimental results. We further find that the transfer between the strongly coupled rings of neighboring LH2 complexes can also be well described with our method. We conclude that our new method accurately describes the EET rate for biologically relevant multichromophoric systems, which are similar to the LH2 complex. Computationally, the new method is very tractable, especially for slow processes. We foresee that the method can be applied to efficiently calculate transfer in artificial systems as well and may pave the way for calculating multidimensional spectra of extensive multichromophoric systems in the future. [ABSTRACT FROM AUTHOR]

An electrostatic field mill (EFM) is widely used to measure the strength of electrostatic fields, the main drawback of which is the occurrence of large measurement errors (up to 15 % in the range from 0 to 1 kV/m). This paper examines the aspects of using transimpedance amplifiers (TIAs) for the tasks of converting the current received from the EFM sensor into voltage, which will make it possible to reduce the instrumental error and ensure the linearity of the atmospheric electrostatic field strength measurement. In the general case, for the functional circuits of the electrostatic field mill, which include a differential transimpedance amplifier, there is the use of two TIA circuits, which are connected in parallel. Despite the simplicity of implementation, such a configuration contains a number of disadvantages and is not optimal. In the paper, a comparative analysis of a typical circuit of a differential TIA and a circuit of an ungrounded differential transimpedance amplifier with zero voltage drop proposed by the authors is carried out. As a result of the analysis, it was established that the designed authentic circuit of the ungrounded differential transimpedance amplifier with zero voltage drop has better parameters of linearity and interference resistance, in contrast to the generally accepted one. The value of the signal-to-noise ratio for the proposed scheme improved by 42 % on average compared to the typical one. The main difference of the proposed scheme is that the stability of the amplification factor is ensured, the influence of the bias parameters of the operational amplifier is leveled, and the overall noise level is reduced. The use of the designed scheme of an ungrounded differential transimpedance amplifier with zero voltage drop could make it possible to increase the accuracy of the measurement of the electrostatic field strength. [ABSTRACT FROM AUTHOR]

In modern discrete functional semiconductor devices and structural elements of micro- and nanoelectronics, use is made of materials with anisotropy of electrical properties. In particular, such materials are crystalline thermoelectrics, layered graphite structures, and strained silicon. In the practical application of these semiconductors, it becomes necessary to measure their kinetic coefficients. However, the electrodynamics of these media differs from that of isotropic ones, which requires the correction of existing methods for measuring the conductivity and concentration of the majority charge carriers. The paper presents a technique for solving the Neumann problem with inhomogeneous boundary conditions for the electric field potential in a rectangular region in a relatively weak magnetic field in a linear approximation. The boundary value problem considered in the paper is encountered in the analysis of measurements of the Hall effect by probe methods. Using the perturbation theory and the Fourier method, an expression for the Hall field potential is obtained and presented in rectangular coordinates as a series of harmonic functions, which is convenient for further application. Practically important expressions for analyzing the results of Hall measurements by probe methods have been obtained for anisotropic samples with flat boundaries. Analysis of the obtained solution and computer simulation of the electric potential in anisotropic semiconductor wafers with flat boundaries are performed. An experimental verification of the obtained distributions of potentials and practical recommendations on the application of the obtained theoretical expressions are presented. [ABSTRACT FROM AUTHOR]

This paper presents a novel survey of high level synthesis (HLS) based hardware security approaches for reusable intellectual property (IP) cores used in consumer electronics and computing systems. A succinct review of all major HLS based hardware security approaches applied on reusable IP cores, along with their design flow and security analysis, is provided. The paper presents a detailed design flow of hardware integrated circuits (ICs) along with vulnerability points where potential attacks/threats are possible. Trustworthy and untrustworthy regimes in the design flow have also been highlighted in the discussion. Further, a discussion of detective and preventive control-based HLS hardware security approaches used for hardware IP cores has also been presented, including an analysis of prominent structural obfuscation, logic locking (logic encryption), and IP core protection (IPP) techniques. Each approach has been lucidly explained in terms of its threat model, algorithm, and security analysis. Finally, a security comparison of hardware IP obfuscation approaches in terms of strength of obfuscation security metric as well as a security comparison of IPP approaches in terms of probability of coincidence security metric, have also been introduced. [ABSTRACT FROM AUTHOR]

Disconnections due to voltage drops in the grid cannot be permitted if wind turbines (WTs) contribute significantly to electricity production, as this increases the risk of production loss and destabilizes the grid. To mitigate the negative effects of these occurrences, WTs must be able to ride through the low-voltage conditions and inject reactive current to provide dynamic voltage support. This paper investigates the low-voltage ride-through (LVRT) capability enhancement of a Type-3 WT utilizing a dynamic voltage restorer (DVR). During the grid voltage drop, the DVR quickly injects a compensating voltage to keep the stator voltage constant. This paper proposes an active disturbance rejection control (ADRC) scheme to control the rotor-side, grid-side and DVR-side converters in a wind–DVR integrated network. The performance of the Type-3 WT with DVR topology is evaluated under various test conditions using MATLAB®/Simulink®. These simulation results are also compared with the experimental results for the LVRT capability performed on a WT emulator equipped with a crowbar and direct current (DC) chopper. The simulation results demonstrate a favourable transient and steady-state response of the Type-3 wind turbine quantities defined by the LVRT codes, as well as improved reactive power support under balanced fault conditions. Under the most severe voltage drop of 95%, the stator currents, rotor currents and DC bus voltage are 1.25 pu, 1.40 pu and 1.09 UDC, respectively, conforming to the values of the LVRT codes. DVR controlled by the ADRC technique significantly increases the LVRT capabilities of a Type-3 doubly-fed induction generator-based WT under symmetrical voltage dip events. Although setting up ADRC controllers might be challenging, the proposed method has been shown to be extremely effective in reducing all kinds of internal and external disturbances. [ABSTRACT FROM AUTHOR]

This paper explores a transformerless static synchronous series compensator (TL‐SSSC) for mitigating voltage distortion in a power distribution line with renewable generations. A novel deadbeat current control scheme with time delay compensation is proposed which models the a‐b‐c three phase line with TL‐SSSC plus its LC filters and predicts the compensating voltages to be injected by the TL‐SSSC. Without resolving measured voltages and currents into positive and negative sequences, the scheme is computationally efficient and effective in mitigating voltage distortion due to faults occurring at different locations along the distribution line. It also eliminates the problem of inaccurate compensation voltage caused by inverter filter choking voltage drop. The paper also analyses the power controllable ranges for a TL‐SSSC under different unbalanced voltage ratios. The proposed TL‐SSSC and control scheme is validated using Typhoon Hardware‐In –Loop (HIL) device. Experimental results on mitigation unbalanced voltages of a 11kV transmission line confirm the effectiveness and high performance. [ABSTRACT FROM AUTHOR]

This paper describes our findings on the molecular association patterns of seven hexacoordinated Sn(IV)(axial-L)2-(5,10,15,20-tetraiodophenylporphyrin) complexes [where L = F-substituted benzoate anions]. The systematic and progressive variation of the fluorine content on the molecular scaffold resembling a rigid wheel-and-axle duo demonstrates that it is possible to induce I⋯F hetero-halogen interactions among other weak interactions such as C–H⋯O, C–H⋯π, π⋯π etc. Hirshfeld surface analysis further supports the role of hetero-halogen interactions in the model compound 6. DFT-based electrostatic potential surface studies show the presence of a σ-hole on the iodine atom and thus vouch for its electrophilic nature in all the observed I⋯F halogen bonds. A homo-halogen I⋯I contact with much non-linearity is observed in 7, and, conspicuously, no F⋯F is found in any of the structures studied due to the hard nature of the fluorine atom. Quantum theory of atoms in molecules (QTAIM) analysis clearly reveals the presence of bond critical points, thus confirming the existence of homo- and hetero-halogen bonds within the studied dimer. Further support for the attractive nature of homo- and hetero-halogen bond interactions is gathered through noncovalent interaction-reduced density gradient (NCI-RDG) analysis, which shows the attractive nature of such interactions. Overall, the combined experimental and theoretical studies presented here showcase the occurrence of both homo- and hetero-halogen interactions and their role in the self-assembly process and associated photophysical properties of metalloporphyrin complexes. [ABSTRACT FROM AUTHOR]

In this paper, the governing equation of a piezoelectric semiconductor (PSC) is derived after a consideration of flexoelectricity and the strain gradient effect. A one-dimensional first-order beam model is obtained through integration across its section. Based on this model, theoretical analysis is carried out for a cantilever PSC nanowire subjected to a time-harmonic transverse shear force. The effects of flexoelectricity and the strain gradient on bending vibration characteristics are investigated, including the natural frequencies and distributions of physical quantities. The results show that the strain gradient effect on the natural frequency and stiffness of a PSC nanowire is greater than that of flexoelectricity, while with regard to the influence on electric potential and carrier concentration, the reverse is true. Our findings shed light on the design and optimization of PSC devices such as energy harvesters at the nanoscale. [ABSTRACT FROM AUTHOR]

Regarding the advances in technology and anxieties around high and growing prices of fossil fuels, government incentives increase to produce cleaner and sustainable energy through distributed generations. This makes trends in the using microgrids which consist of electric demands and different distributed generations and energy storage systems. The optimum operation of microgrids with considering demand-side management increases efficiency and reliability and maximize the advantages of using distributed generations. In this paper, the optimal operation scheduling and unit commitment of generation units installed in a microgrid are investigated. The microgrid consists of technologies based on natural gas that are microturbine and phosphoric acid fuel cell and technologies based on renewable energy, including wind turbine and photovoltaic unit along with battery energy storage system and plug-in electric vehicle commercial parking lot. The goal of the paper is to solve a multi-objective problem of maximizing revenues of microgrid operator and minimizing emissions. This paper uses an augmented epsilon constraint method for solving the multi-objective problem in a stochastic framework and also implements a fuzzy-based decision-maker for choosing the suitable optimal solution amid Pareto front solutions. This new model implements the three type of the price-based and incentive-based demand response program. It also considers the generation reserve in order to enhance the flexibility of operations. The presented model is tested on a microgrid and the results demonstrate the efficacy of the proposed model economically and environmentally compared to other methods. [ABSTRACT FROM AUTHOR]

According to statistics, solid product formed by the reaction between SF6 gas and metal electrodes at the connecting joint of ultra-high-voltage direct current (UHVDC) wall bushing is likely to adhere to the surface of insulating materials, which may seriously threaten the insulation of the bushing. Thus, studying the effect of the solid products on DC surface flash-over voltage is of great significance for evaluating the internal insulation of UHVDC wall bushing. The electrical parameters of the solid products were measured and compared with those of epoxy-impregnated composite insulating materials. The comparison result shows that there is a significant difference between them, which demonstrate that the solid products may have an impact on the DC flash-over voltage of epoxy-impregnated composite insulating materials. Furthermore, by means of the DC surface flash-over platform, the characteristic of the surface flash-over voltage of the epoxy-impregnated composite insulating materials with the solid products attached directly is analyzed. It is found that the decrease in the surface flash-over voltage is closely related to the type of solid product, gas pressure, distance between electrodes, way of attachment, etc. [ABSTRACT FROM AUTHOR]

This paper presents a scheme for rotor position estimation from standstill to nominal speed. The proposed scheme is particularly suited for surface mounted permanent magnet synchronous motors and for slotless permanent magnet synchronous motors with completely smooth cylindrical rotor, which cannot be operated with state-of-the-art sensorless methods seamlessly from standstill. At standstill and very low speed, the position is estimated by using signal injection. A systematic distortion in the position estimation that is due to asymmetries in the motor parameters is identified and compensated. The rotor polarity is identified by a special process based on the estimation of the back electromotive force (back EMF) induced by a minimal rotor motion. At high speed, the position is estimated by using a linear back EMF observer. Different observer gains are used at different speed ranges, so that the position estimate is reliable even at low speed. The combination of these two approaches enables sensorless motor control in the full speed range including standstill. Experiments demonstrate the accuracy of the proposed estimation scheme and its robustness under different thermal conditions. This paper is accompanied by two videos demonstrating sensorless operation. [ABSTRACT FROM AUTHOR]

Abstract: We have developed flexible top emission organic light-emitting devices by using sputtered Ni films on the parylene coated copy paper substrates. The Ni film grew through the coalescence of the Ni islands nucleated on the cellulose fiber patterns. The parylene, acting as a buffer layer for preventing water absorption, affected the morphological and electrical characteristics of the deposited Ni films. The flexible top emission diode device composed of Ni anode and Ca/Ag semitransparent cathode exhibited a luminance of ∼1 cd/m2 at a driving voltage of 14.5 V. [ABSTRACT FROM AUTHOR]

In this work we describe the Square Wave Anodic Stripping Voltammetry (SWASV) electrochemical technique for the determination of lead (Pb2+) and cadmium (Cd2+) metal ions at concentration of sub-part per billion (ppb) in aqueous solution. Moreover, simple and low-cost procedures for the fabrication of high performance working nano-electrode are reported. The electrode structure consists of a graphene paper (GP) $240~\mu \text{m}$ thick with the function of electrical conductor and substrate, a layer of nafion 0.5- $0.7~\mu \text{m}$ thick onto the graphene paper and bismuth nanoparticles embedded in the nafion thin layer. The bismuth nanoparticles were fabricated by electrodeposition starting from Bi(III) ions, employing a key step of hydrogen ions of nafion $\text{H}^{\mathbf {+}}$ exchange with bismuth ions Bi(III). This procedure is aimed to improve the bismuth nanoparticles concentration. The SWASV applied to the low-cost nanoelectrode allows detecting Pb2+ and Cd2+ at concentration as low as 0.1 ppb. [ABSTRACT FROM AUTHOR]

Provides instructions and guidelines to prospective authors who wish to submit manuscripts. [ABSTRACT FROM AUTHOR]

A novel polymer-stabilized blue phase liquid crystal display (PS-BPLCD) using an optimized BPLC for new wall-electrode cell structure and also new driving method has been developed. Those technologies enable BPLCDs to apply conventional source driver IC in AMLCD applications. This novel PS-BPLCDs successfully achieved high-performance LCDs with over 2 times higher optoelectronic properties and a superior reliability. [ABSTRACT FROM AUTHOR]

Self-aligned coplanar oxide TFTs have been developed for large-sized UHD OLED TV. Metallized active films were employed as source/ drain regions. By applying light shield layer, it was made possible to suppress photo-induced threshold voltage shift and obtain excellent output characteristics. The maximum difference of threshold voltages of a-IGZO TFTs on Gen. 8.5 glass is approximately 0.57V. Also, a-IGZO TFTs reveal good reliability showing threshold voltage shift of 0.07V and 0.03V after 1h of PBTS and 10h of CS, respectively. This work should play an important role in commercializing large-sized UHD OLED TV. [ABSTRACT FROM AUTHOR]

This paper proposes a new full‐order adaptive observer algorithm to overcome the instability of speed sensorless vector control system of induction motor at low speed, especially at extremely low speed. The algorithm consists of the improved feedback matrix algorithm and the improved speed adaptive law algorithm. By establishing an observer state error equation considering the non‐linear voltage error of the inverter and the stator resistance voltage drop, a feedback matrix was designed to reduce the effect of inverter's non‐linear voltage error and stator resistance voltage drop on speed estimation. Meanwhile, this paper improves the traditional adaptive law. The basic idea is to add compensation amount equivalent to the non‐linear voltage error, and the compensation amount is adaptive to the running speed and load to improve the motor speed estimation accuracy at low speed. Extensive experimental tests have been carried out to evaluate the performance of the proposed algorithm using a 2.2 kW induction motor experimental platform. The experimental results show that the algorithm presented in this paper can guarantee the stable operation of the motor under the rated‐load and 180% rated‐load at low, extremely low and 0 speed with good dynamic and static characteristics. [ABSTRACT FROM AUTHOR]