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One of the most important parts of semiconductor etch tools is the electrostatic chuck (ESC), which ensures secure wafer holding during fabrication and uniform temperature distribution from center to perimeter of the wafer during plasma etching. In this study, we investigated the thermal and electrical analysis of the ESC to ensure the temperature uniformity of the wafer via analytical multi-physics simulation including backside gas (BSG) flow between the wafer and ESC surface while the high voltage direct current (HVDC) power was applied in the ESC. We devised a bipolar-Coulomb type ESC and compared experimental data with theoretical and computational results. The chucking pressure along the HVDC magnitudes from 500 to 1000 V was investigated through 1D electric circuit and 2D simulation using ANSYS Maxwell. And we investigated the temperature change of the wafer when the BSG pressure changes from 0 to 15 Torr through 1D thermal circuit and 3D simulation using ANSYS Fluent. The 1D equivalent electric circuit showed the same trend with an error rate of 6.94% with 2D simulation and 58.75% with an experiment on average. The 1D equivalent thermal circuit also showed the same trend with an error rate of 0.44% with 3D simulation and 1.52% with an experiment on average. [ABSTRACT FROM AUTHOR]

The traditional active neutral-point-clamped (APC) dc–ac converter maintains great common-mode voltage with high-frequency (CMV-HF) reduction capability, so it has limited voltage gain. This article presents a new five-level APC (FL-APC) dc–ac converter capable of voltage step-up in a single-stage inversion. In the suggested design, a common ground not only reduces the CMV-HF but also improves dc-link voltage usage. While comparing with traditional two-stage FL-APC dc–ac converter, the proposed design has lower voltage stresses and greater uniformity. While improving overall efficiency, the suggested clamped dc–ac converter saves three power switches and a capacitor. Modeling and actual tests have proven the suggested APC inverter’s overall operation, efficacy, and achievability. The proposed circuit is finally tested with fault clearance capability. [ABSTRACT FROM AUTHOR]

The dual-active-bridge (DAB) is a typical topology of dc–dc converter for bus connection, voltage conversion, power transmission, and electrical isolation in dc power grids. The open-circuit switching fault (OCSF) may threaten the safe operation of DAB and should be eliminated in time. However, the researches on parasitic parameters mainly focus on traditional dc–dc converters, and there are still few discussions on parasitic parameters in the high-frequency dc–dc converter such as DAB. The power components are usually considered without parasitic parameters in OCSF analysis and tolerant control, leading to deviations in modality analysis and practical control for DAB. To solve this issue, the modality analysis considering parasitic parameters during OCSF in DAB is investigated, and the sneak circuits and electrical characteristics with parasitic parameters are discussed in this article. Besides, to realize fault tolerance for DAB during OCSF considering parasitic parameters, a new fault tolerance control strategy including modeling, topology transformation principle, and practical control architecture are also proposed. Compared with conventional fault tolerance strategy, the proposed strategy will be more efficient, rapid and feasible for DAB during OCSF process. The experimental results in DAB prototype verify correctness and effectiveness of analysis and proposed strategy. [ABSTRACT FROM AUTHOR]

Significant effort has been dedicated to developing integrated onboard charging circuits for electric vehicles, aiming to improve cost, range anxiety, and charging convenience. The dual-inverter drivetrain topology has attracted particular attention as a platform for developing such solutions, being previously leveraged for the implementation of dc and single-phase ac onboard charging. This work proposes an integrated three-phase onboard charger based on the dual-inverter drivetrain. The proposed converter is implemented with minimal change to the dual inverter and no additional power electronics by introducing a split-phase electric machine. A mathematical model is developed, decomposing the system into four decoupled subsystems, individually responsible for charging, driving, grid common-mode current, and zero-sequence current generation, respectively. In light of this model, a novel space-vector pulsewidth modulation technique is introduced to ensure charging current control while generating no flux-producing, nor zero-sequence currents, and having superior common-mode performance. Simulation-based and experimental verification is conducted on a 7.2-kW scaled-down prototype to prove the charging concept, as well as the common-mode current elimination. [ABSTRACT FROM AUTHOR]

Contribution: Two general rules for calculating, in the time domain, step discontinuities of voltages and currents in electric circuits, combining physical principles and basic mathematical treatment. The two general rules, resulting from a formal method of analysis, provide a straightforward way to update the states of a circuit, immediately after the occurrence of switching or impulsive excitation. Among its advantages, they can be used to simplify the numerical simulation of elaborate circuit topologies by avoiding approximate models of impulsive sources or switches. Background: In most engineering undergraduate textbooks, the effects of switching and impulsive sources on higher order electric circuits are usually studied for the particular case of linear time-invariant (LTI) circuits in the Laplace transform domain. This approach, however, can be time consuming and demands little reasoning on the physical principles of circuit operation. Moreover, it is not adequate for linear time-variant or nonlinear circuits. Intended Outcomes: Step discontinuities in electric circuits, caused by switching or impulsive sources, are identified and calculated through the method, allowing complete responses to be obtained afterward. Not only can the method be extended to linear time-variant and nonlinear circuits but it also has interesting consequences in numerical simulation of circuits. Application Design: An application exercise and a set of conceptual questions on the subject were proposed to electrical engineering students. Findings: The analysis of the educational experiment indicates that applying the method presented herein improves the students’ ability to obtain initial conditions of circuits, being a more straightforward and effective approach than using Laplace transform techniques. [ABSTRACT FROM AUTHOR]

Contribution: This article describes the implementation, assessment, and evaluation of conceptual-based writing exercises in an introductory course on electric circuit analysis. Background: Students’ struggles in gateway courses such as circuit analysis are often traced to inadequate metacognitive skills on the part of the student as well their misconceptions regarding fundamental phenomena related to the course. Writing is known to be a powerful tool for insight into a student’s thought process and to foster metacognitive activity. Research Questions: What effect does the use of short writing exercises have on students’ understanding of fundamental concepts related to the behavior of electric circuits operating at dc? What effect does the use of the conceptually based writing exercises have on students’ ability to justify their responses when answering conceptual questions related to basic electric circuit concepts? Methodology: In the first semester of the study, a single writing exercise was given and in the second semester, a total of five such exercises were administered. In each semester, students were separated into “at-risk” and “not at-risk” groups based on their responses to the first writing exercise. A $2 \times 2 \times $ (2) mixed analysis of variance (ANOVA) was conducted, with at-risk/not at-risk and semester/semester between-subjects factors and pre-test/post-test on a multiple-choice conceptual-based exam a within-subjects factor. Findings: Results suggest that only the at-risk group may have benefited in terms of deepened conceptual understanding and the ability to justify their responses from the use of multiple conceptual-based writing exercises. [ABSTRACT FROM AUTHOR]

In this letter, a novel variation of Generative Adversarial Network (GAN) is proposed and used to predict device and circuit characteristics based on design parameters. Unlike regular GAN which takes white noise as inputs, this modified GAN uses device or circuit parameters as inputs. Unlike regular Physics-informed GAN (PI-GAN) which incorporates differential equations in the training process, this modified GAN learns physics through the inputs and has one extra step of supervised learning. FinFET is used as a device example and Technology Computer-Aided-Design (TCAD) is used to generate its current-voltage (${I}_{D}{V}_{G}$ , ${I}_{D}{V}_{D}{)}$ and capacitance-voltage (${C}_{G}{V}_{G}$) curves as the training data by varying the gate length ($\text{L}_{\text {G}}{)}$ , fin top width ($\text{W}_{\text {TOP}}{)}$ , and gate metal workfunction (WF). A CMOS inverter with source contact defects is used as a circuit example and a SPICE simulator is used to generate its Voltage Transfer Characteristics (VTC) by varying the source contact resistances. We show that 1) the GAN model is able to generate both the device and circuit electrical characteristics based on the input parameters, 2) it can predict the characteristics of the device and circuit out of the training range (in a testing volume 3.7x to 4.6x larger than the training volume), and 3) it is further verified on experimentally measured data in the inverter case that it does not overfit and has learned the underlying physics. [ABSTRACT FROM AUTHOR]

This paper proposes a systematic method for the identification of the load circuit parameters (say the $\boldsymbol{R}$ , $\boldsymbol{L}$ , and $\boldsymbol{C}$ elements) based only on the information of the instantaneous voltage and current measured at the point of common coupling (pcc). Geometric Algebra (GA) and concepts of differential geometry are used to produce a rigorous mathematical framework. The identification is formulated as a multidimensional geometrical problem that is solved conveniently by means of GA. Once the passive elements of the load have been identified, the active and reactive powers can be computed from first electromagnetic principles (Maxwell Equations). The theory is general and is verified with linear and nonlinear circuits. The paper shows single-phase circuits but the theory can be extended to three-phase circuits. The method is easy to program and has shown to be very robust for all tested cases. Because of its generality, the method presented will find applications beyond electric circuits. [ABSTRACT FROM AUTHOR]

Nonlinear system design is often a multiobjective optimization problem involving the search for a design that satisfies a number of predefined constraints. The design space is typically very large since it includes all possible system architectures with different combinations of components composing each architecture. In this article, we address nonlinear system design space exploration through a two-step approach encapsulated in a framework called fast design space exploration of nonlinear systems (ASSENT). In the first step, we use a genetic algorithm to search for system architectures that allow discrete choices for component values or else only component values for a fixed architecture. This step yields a coarse design since the system may or may not meet the target specifications. In contrast to prior works on design space exploration that rely on forward design, we use an inverse design in step 2 to search over a continuous space and fine-tune the component values with the goal of improving the value of the objective function. We use a neural network (NN) to model the system response. The NN is converted into a mixed-integer linear program for active learning to sample component values efficiently. We illustrate the efficacy of ASSENT on problems ranging from nonlinear system design to the design of electrical circuits. Experimental results show that ASSENT achieves the same or better value of the objective function compared to various other optimization techniques for nonlinear system design by up to 53%. We improve sample efficiency by 6– $12\times $ compared to reinforcement learning-based synthesis of electrical circuits. [ABSTRACT FROM AUTHOR]

In many technical applications at low frequency, wave propagation effects can be neglected, and Darwin models promise to accurately describe the electromagnetic fields because they include resistive, inductive, and capacitive terms. In a former work, we developed an efficient, frequency stable method to solve the full Maxwell model, i.e., without neglecting any effect. This method employs the electro-quasistatic gauge, which allows to cleanly separate the calculation of capacitive effects in a first step, from the calculation of inductive effects in a consecutive second step. The Darwin model in frequency domain and electro-quasistatic gauge can easily be derived from this method by neglecting just one term, namely the induced displacement current. Here, we compare this Darwin model with the full Maxwell model, e.g., for the example of an $RLC$ -series circuit. We found that this Darwin model cannot describe the interaction between $L$ and $C$ in the $RLC$ -circuit. [ABSTRACT FROM AUTHOR]

This article introduces a complementary criterion for flashover (FOV) of polluted insulators based on the concept of equivalent impedance variation with discharge length and leakage current. An analytical electrothermal model enabling the calculation of critical FOV voltage and critical current of polluted insulators is developed using this complementary criterion and the equivalent impedance criterion. It is shown that the critical parameters depend on the thermal characteristic of the discharge and the components of the equivalent electrical circuit. The comparison of the computed FOV voltage and critical current is in good accordance with the experimental ones for a laboratory insulation flat sample model with different applied voltage waveforms. The application of the developed model to actual insulators destined for 11-kV systems, by including equivalent salt density deposit (ESDD) and the form factor, shows that FOV voltage values match very well with the experimental data in clean fog test conditions. [ABSTRACT FROM AUTHOR]

High-power railgun circuit design and construction is costly and time-consuming. Verifying the behavior and performance of the circuit using a circuit simulator before hardware implementation is faster and more cost-effective. In this brief, a rail type electromagnetic launcher is modeled as a controlled voltage source to the pulse forming circuit and a real-time simulation is performed on that circuit. To validate the developed real-time model of the railgun circuit, the current pulse generated is given as an input to the finite element model developed in LS-Dyna. Obtained results of finite element (FE) simulation and real-time (RT) simulator are compared from a mechanical viewpoint. An iterative procedure is utilized to exactly model the railgun in real-time simulation along with finite element simulation. In the iterative process, the result of the inductance gradient obtained in the finite element simulation is plugged back into the real-time simulator. The current obtained in the real-time simulator is given as an input to finite element simulation. Among the models, the linear fit model of inductance gradient has performed better. A tolerance condition of least approximate error in the muzzle velocity is selected for termination of iterations. [ABSTRACT FROM AUTHOR]

This article analyzed and compared the complex permeance model (CPM) and nonlinear analytical model (NAM) for surface-mounted permanent magnet (SPM) motor using a voltage source inverter (VSI). For linear CPM, the slotting effect is represented using the improved complex permeance function that describes the real slot shape rather than infinitely deep slot. NAM is extended from CPM and it replaces the magnetic potential drop of stator iron by the equivalent virtual current in the slot-opening and tooth-tip to account for the nonlinearity effect. The nonlinear inductance of SPM motor including the main phase inductance, slot leakage inductance, tooth-tip leakage inductance, and end winding leakage inductance is calculated using the frozen permeability method, which is the key to solve the electric circuit with VSI. The instantaneous back electromotive force (EMF) is calculated from the nonlinear back EMF coefficient and the back EMF neglecting iron nonlinearity. The electromagnetic torque obtained from motor model is used in the mechanical model and then the rotational speed and rotor position are obtained for the electric circuit model. Hence, the iterative solving process for the motor system is established to calculate the transient performance of SPM motor using VSI. Compared with CPM, NAM can greatly improve the calculation accuracy, which is also validated by both finite-element model and experiment. Besides, the proposed NAM is computationally efficient, which is useful for both motor design and motor control. [ABSTRACT FROM AUTHOR]

This article proposes a new approach using the T-A formulation coupled to lumped parameters in the electrical circuit, considering the skin-depth approach. The finite-element method models the superconducting layer, the electrical circuit models the stabilizer and substrate layers as lumped parameters, and a coupling engine links both of them. The ac losses have been calculated by both T-A 1-D and T-A 2-D formulations: the first one uses the approach proposed in this article, and the second, two current vector potential components. For the three formulations, we have studied the average power dissipation as a function of frequency and current, and the peak current as a function of the frequency. We have compared the T-A 1-D and T-A 2-D formulations to H formulation results previously studied. Comparing the results of the average power dissipation, we have found the maximum error to be around 10.5% in T-A 1-D and 35% found in T-A 2-D. The efficiency of the proposed technique was evaluated as 16 times less costly when compared to the T-A 2-D formulation. [ABSTRACT FROM AUTHOR]

In this article, we present the characterization and an experimentally validated electromechanical model of a dual-transduction receiver for electrodynamic wireless power transfer (EWPT) system. This dual-transduction EWPT receiver contains two unimorph-type, series-connected piezoelectric transducers and an electrodynamic transducer within a compact footprint and low-profile design. The receiver makes simultaneous use of both piezoelectric and electrodynamic transducers to generate electrical power while operating at its torsion mode mechanical resonance at ∼744 Hz. The electromechanical system behavior and output performance under low-frequency, magnetic near-fields are analyzed by establishing an equivalent lumped-element equivalent electrical circuit model. A prototype device is fabricated, assembled, characterized, and the experimental results are compared with the model predictions under various excitation and loading conditions. A maximum of 49 μW average power is generated by the prototype under 120 μTrms, which corresponds to 0.54 mW·cm–3 power density and 37 mW·cm–3·mT–2 normalized power density. This chip-sized (0.09 cm3) design offers an innovative and volume-efficient architecture for application in wirelessly charging wearable and implantable medical devices. [ABSTRACT FROM AUTHOR]

Spikes and rhythms organize control and communication in the animal world, in contrast to the bits and clocks of digital technology. As continuous-time signals that can be counted, spikes have a mixed nature. This article reviews ongoing efforts to develop a control theory of spiking systems. The central thesis is that the mixed nature of spiking results from a mixed feedback principle, and a control theory of mixed feedback can be grounded in the operator theoretic concept of maximal monotonicity. As a nonlinear generalization of passivity, maximal monotonicity acknowledges at once the physics of electrical circuits, the algorithmic tractability of convex optimization, and the feedback control theory of incremental passivity. We discuss the relevance of a theory of spiking control systems in the emerging age of event-based technology. [ABSTRACT FROM AUTHOR]

The correct assessment of battery states is essential to maximize battery pack performances while ensuring reliable and safe operation. This article introduces EIS2MOD, a novel modeling framework for li-ion cells based on distribution of relaxation time. A physically-based electric circuit model is developed starting from electrochemical impedance spectroscopy and open-circuit voltage measurements. Distribution of relaxation time (DRT) is applied to deconvolve the electrochemical phenomena from the EIS. The presented methodology is based on: DRT calculation from EIS; DRT analysis for ECM configuration; and model parameters extraction and fitting. The proposed framework is applied to large format li-ion pouch cells, which are tested over the whole state of charge (SoC) range and a wide temperature range (−10 °C to 35 °C). Different current profiles have been tested to validate the model, showing its high accuracy in reproducing the battery cell behavior (e.g., RMSE on the battery terminals voltage lower than 1.50% for driving cycle simulations at variable temperature and SoC). An additional advantage of EIS2MOD is its light computational load thus offering an attractive framework for battery management system implementation. [ABSTRACT FROM AUTHOR]

This article introduces a push–pull series connected (PPSC) ac–dc converter intended for high-voltage direct current applications. The proposed topology requires fewer submodules compared to a standard modular multilevel converter (MMC) to withstand the same dc voltage. Each converter phase unit is connected to its corresponding phase on the ac side via a center-tapped single-phase transformer which also provides the galvanic isolation needed in most applications. The required arm inductance can be merged into the transformer leakage inductance avoiding the need for additional inductors. In this article, both the design and operation of the converter are discussed in detail. Furthermore, a comparison of the PPSC and MMC in terms of energy storage requirements and efficiency is presented. The converter concept and the control strategy proposed is validated by computer simulations using the piecewise linear electrical circuit simulation (PLECS) simulation package as well as through experiments on a small-scale, 300-V, 2-kW laboratory prototype. [ABSTRACT FROM AUTHOR]

The issue of sliding-mode control (SMC) design is studied for a class of nonlinear semi-Markovian switching systems (S-MSSs) via T–S fuzzy approach. Compared with previous literature, novel integral sliding-mode surfaces (ISMSs) are developed to depend on the designed controller gains and projection matrices. The aim of this work is to design an appropriate fuzzy SMC law under complex stochastic semi-Markovian switching process. For this purpose, the novel ISMSs are developed under the T–S fuzzy modeling framework. Then, based on the weak infinitesimal operator theory, sufficient conditions are given for stochastic stability criteria relying on the sojourn-time. Furthermore, an appropriate fuzzy SMC law is proposed to drive the state signals onto the predefined fuzzy manifold. Finally, an electric circuit model illustrates the effectiveness of the theoretical findings. [ABSTRACT FROM AUTHOR]

The letter provides a geometrical interpretation of frequency in electric circuits. According to this interpretation, the frequency is defined as a multivector with symmetric and antisymmetric components. The conventional definition of frequency is shown to be a special case of the proposed theoretical framework. Several examples serve to show the features, generality as well as practical aspects of the proposed approach. [ABSTRACT FROM AUTHOR]

Wireless power transfer (WPT) is a safe and convenient technology for battery charging thanks to the elimination of electrical contact. Despite the great advantages, the electromagnetic interference (EMI) noise generated by a WPT system coulddegrade the performance of nearby electrical circuits. In particular, common-mode (CM) EMI noise generated by the WPT system will conduct along the cable and radiate in high frequencies, thus becoming one of the concerns. In this article, the noise source and current path of the conducted CM EMI noisefrom a Qi-compliant WPT system for mobile applications are analyzed. The transfer function relating the CM EMI noise to the noise source voltage is derived analytically in the frequency domain. The noise source voltage is measured in the time domain and then converted to the frequency domain via fast Fourier transform. The conducted CM EMI spectrum is predicted by multiplying the spectrum of noise source voltage by the transfer function. The prediction matches well with measurement. The analysis and modeling explain the mechanism of the CM EMI noise and provide guidelines to reduce the CM EMI noise. [ABSTRACT FROM AUTHOR]

Frequency response analysis (FRA) is a popular tool to detect transformer winding deformation faults. It has been recently used to diagnose the winding inter-turn short circuit fault of the electric machine. The application of FRA is based on the fact that the winding can be equivalent to an electrical circuit consisting of resistance, inductance, and capacitance. Therefore, to obtain an accurate broadband equivalent circuit model of synchronous machine and perform the fault analysis and diagnosis, this paper introduces the gray box model technique based on the state space and genetic algorithm. The electrical circuit of a form-wound coil of a 4 kW machine with known electrical parameters is used to verify the proposed method primarily. Besides, the equivalent circuit modeling is carried out and experimentally verified on an actual 5 kW synchronous machine. Finally, the fault simulation analyses of winding inter-turn short circuits are performed based on the proposed equivalent electrical circuit. The verification result shows that the circuit parameters identified by the proposed method are accurate. Moreover, the fault simulation results indicate that the inter-turn short circuit faults can cause apparent variations in the frequency response curves. It is feasible to detect the winding fault of the synchronous machine by the FRA method. [ABSTRACT FROM AUTHOR]

This article addresses the investigation of sliding-mode control (SMC) for slow-sampling singularly perturbed systems (SPSs) with Markov jump parameters. As a new attempt, the SMC strategy is considered in the study of discrete-time Markov jump SPSs. Subsequently, in order to design a sliding-mode controller to ensure the stability of the proposed system, a novel integral sliding surface is constructed, and an SMC law is synthesized to ensure the reachability of the sliding surface. Through the utilization of Lyapunov stability and SMC theory, sufficient conditions are derived to ensure the state trajectories of the system are driven to a predefined sliding surface and the closed-loop sliding mode dynamics are stochastically stable. Finally, the applicability of the proposed SMC strategy is verified by a numerical example and a practical electric circuit model. [ABSTRACT FROM AUTHOR]

This article introduces an adaptive self-tuned controller IC for resonant wireless power transfer (RWPT) transmitters. The controller IC comprises an on-the-fly very-high-frequency tracking hardware with high resolution and an independent high-resolution digital pulsewidth modulator (PWM)-based (HR-DPWM) current programmed control. These facilitate precise frequency generation as well as adaptive tuning of the reactive components in the matching network, which translate into tight current/power regulation capabilities while retaining optimized power transfer conditions on the transmitting side. The controller IC enables to effectively disengage the power-delivery capabilities from the variations of the resonators, electrical circuits, and wireless medium. The controller core is based on a fully synthesizable digital architecture that has been realized through HDL tools, and several key building blocks have been developed and described in detail: a delay-line-based phase detector, high-resolution digital frequency synthesizer, and HR-DPWM. To fully exploit the benefits of digital electronics, reduce power consumption, and save area, the digital core of the controller has been designed completely through asynchronous architecture, eliminating the need of high-speed clock and its related hardware. The mixed-signal controller IC has been designed, implemented, and fabricated in 0.18-μm 5-V CMOS process, resulting in effective silicon area of 0.6 mm2. To demonstrate the mixed-signal controller IC in closed-loop operation of a wireless power system, an experimental 20-W resonant capacitive-based WTP system has been designed and validated. The effectiveness of the controller is well demonstrated and evaluated at the MHz range up to 200 mm misalignment, meeting the strict requirements of resonant-based WPT systems. [ABSTRACT FROM AUTHOR]

A power supply able to generate a pulsed large current (∼26 kA) with a flattop period > 10 ms for a heavily inductive load was designed based on the sequentially fired pulse forming network (SFPFN) scheme with high-energy-transfer efficiency. To overcome the high voltage stress on switching devices due to the SFPFN scheme, a novel electrical circuit topology was developed. In particular, the current changing rate (di/dt) on switching devices is limited by new designs of crowbar branch and pulse-forming unit (PFU). The assembled power supply is shown to provide an output current of a flattop of 26 kA and 12 ms on a load of 40 μH and 4.24 mΩ with the predicted improvement in energy transfer efficiency. [ABSTRACT FROM AUTHOR]

Simple low-temperature pulsed power dissociation method for high resistive liquid is proposed in this article. Active high voltage rebound tailing pulse (RTP) diodes are adopted to conventional high voltage pulse power sources. In order to explain this method, the study was performed using deionized water (DIW) (high resistive $>17~\text{M}\Omega \cdot $ cm) electrolysis with two immersed electrodes. The forward pulses, the full-width at half-maximum (FWHM) of 400 ns and forward voltage (7 kV) with rising-up ratio (dV/dt) of 1011 V/s, were applied to the electrodes. When a 5 kV RTP diode was simply adopted to this electrical circuit and DIW load in series, the high forward voltage pulse and continuous high reverse current were applied to this circuit. Then, H2 was generated at the anode electrode and OH radical (OH) in the water vessel. Those phenomena were apparently dependent on the anode electrode area. At the beginning of the forwarded high voltage application, the circuit behaved as capacitance load with generated ions and built up charges at the interface between DIW and the electrode. Continuous rebounded high reverse voltage and highly built-up reverse recovery charges induce avalanche breakdown of RTP diode. The rebounded electrical current was found to be collected in the circuit, accompanied by the generation of hydrogen and OH, as well as the tailing current flowing at the interface as a resistive load. In consequence, we point out that rebounded electrons injected from the surrounding water to the anode electrode interface induced the water electrolysis characteristically, according to RTP-diode inserted in the circuit. [ABSTRACT FROM AUTHOR]

Transient voltage distribution due to steep-fronted surges must be taken into account during the machine's design as it can lead to main and turn insulation failure. In medium voltage machines, the end-windings region has a considerable percentage of the coil length and plays an important role during transient studies. This article has the purpose of verifying the influence of end-windings on the transient voltage distribution by using a three-phase simulation model in which transient magnetic fields and electric circuit elements are coupled. The transient simulation and the calculation of the electrical parameters used in the model are done employing the Finite Elements Method (FEM). To verify the influence on the results, simulations for different surge rise times are performed, considering and neglecting the end-windings model. As main results, the intercoil and interturn voltages are analyzed for all turns from the three phases of one winding group. The model is validated by measurement results. It is shown that the end-windings, indeed, affect the transient voltage distribution for both, interturn and intercoil voltages, regarding the rate of rising (slope), instant, and the amplitude of the peak voltages. Moreover, all three phases are affected by the end-windings, especially for the turn-to-turn voltages. [ABSTRACT FROM AUTHOR]

System efficient electrostatic discharge (ESD) design is an effective method for simulating the ESD behaviors of a system. Based on this simulation method, this article mainly investigates the transient behaviors of a system-level ESD protection circuit with and without a 2.5 V power supply. During power-on state, latch-up levels of a feedback power clamp protected by off-chip elements are predicted and mainly analyzed under machine model stress. During power-off state, the physical failure of a hybrid-triggered power clamp under surge stress is investigated. In addition to the utilization of transmission line pulsing (TLP) I-V curves, transient TLP waveforms are also used for building the component models in the system-level ESD protection circuit. Moreover, the relevant measurements for the power-on state and power-off state are included in this article for verifying the simulation results. For ESD designers, this article provides a complete modeling and analysis process of co-design protection circuit to investigate the electrical behaviors. [ABSTRACT FROM AUTHOR]

This paper describes a chamber and recipe-independent fault detection and classification (FDC) indicator using the example of aluminum sputtering tools. We developed this indicator to detect abnormal discharge in an aluminum sputtering chamber when using a legacy FDC system. Abnormal discharge has several modes in the sputtering chamber, with abnormal discharge to a wafer commonly causing pattern defects. The indicator has been improved to detect only this problem, and to minimize the impact of false alarms that cause a loss of equipment productivity. The indicator can be readily extended to new chambers and the control limits are easily set for all recipes. This is because the equation for the indicator is very simple, and both the equation and the control limits are common to all sputtering chambers and recipes. It can therefore significantly reduce the setup work required of engineers, which is one of the biggest challenges in high-mix semiconductor manufacturing. The indicator is easily applied to newly installed tools at start of production and restrains the number of scrap wafers at minimum level. We also describe the mechanism of trace data changes in abnormal discharge modes using equivalent electrical circuits. [ABSTRACT FROM AUTHOR]

Defective pixels always exist in an uncooled infrared focal plane array (IR FPA), and have a significant impact on image quality. To fundamentally reduce defective pixels and improve IR FPA’s reliability, failure analysis (FA) is critically needed. In this work, a self-test (ST) method is proposed to detect the structural failures of uncooled IR FPA. Based on the lumped thermal parameters of a pixel, a structural failures model is presented, and an electrical circuit is designed. The insufficient released, normal released, over released and contaminated IR FPAs are measured. The measured results show that their lumped thermal parameters have a clear differentiation, which not only experimentally verifies the validity of this method, but also shows that it is an effective method for nondestructive analysis of structural failures. [ABSTRACT FROM AUTHOR]

This article investigates the insulation design for printed, planar, coreless, and high-frequency transformers with high isolation-voltage. By using finite element analysis on 2-D axial-symmetry, the transformer circuit parameters and electric field distribution are modeled and estimated. Several transformers are designed for an operating frequency of 6.78 MHz. The high frequency, coreless design allows for using thicker insulation material while ensuring a high transformer efficiency. The inclusion of the coupling capacitance in the design optimization results in several design solutions with the same figure of merit, but with different footprint and isolation voltages. Moreover, high electric fields are identified around the sharp edges of the printed circuit board (PCB) windings. Finally, the electrical and isolation performance is verified experimentally. The measured electrical properties are close to the simulated values, validating the chosen model. Breakdown tests demonstrate the feasibility of isolation voltage levels up to several tens of kilovolts. The majority of breakdowns occurs at the outer edge of the PCB winding that was identified as a high-field area. Additionally, a concept for grading the electric field of PCB windings is also proposed. Based on the results, the design aspects are discussed in detail for planar, high-frequency isolation transformers with medium-voltage isolation level. [ABSTRACT FROM AUTHOR]

Researchers relying on electrochemical impedance spectroscopy need to decide which equivalent electrical circuit to use to analyze their measurements. Here, we present an identification algorithm based on gene expression programming to support this decision. It is accompanied by some measures to enhance the interpretability of the resulting circuits, such as the removal of redundant components to avoid overly complex circuits. We also provide the option to depart from an initial population of widely applied circuits, allowing for quick identification of known circuits that are capable of modeling the measurement data. As the number of measurements per experiment is typically rather limited in real-life experiments, we examine the number needed to find an adequate circuit topology for two example circuits. Next, the algorithm is tested on impedance simulations for a variety of circuits. Noise robustness is evaluated by subjecting the impedance measurements to increasing amounts of Gaussian noise, demonstrating that the algorithm still works well even for noise levels that are significantly higher than what is typically encountered in practice. Finally, we validate the algorithm by identifying the appropriate circuit for impedance measurements from a biological application. [ABSTRACT FROM AUTHOR]

Real-time identification of electrical equivalent circuit models (ECMs) is a critical requirement in many practical systems, such as batteries and electric motors. Significant work has been done in the past developing different types of algorithms for system identification using reduced-order ECMs. However, little work was done in analyzing the theoretical performance bounds of these system identification approaches. Given that both voltage and current are measured with error, proper understanding of theoretical bounds will help in designing a system that is economical in cost and robust in performance. In this article, we analyze the performance of a linear recursive least squares (RLS) approach to ECM identification and show that the LS approach is both unbiased and efficient when the signal-to-noise ratio is high enough. However, we show that when the signal-to-noise ratio is low–resembling the case in many practical applications–the LS estimator becomes significantly biased. Consequently, we develop a parameter estimation approach based on the total LS method and show it to be asymptotically unbiased and efficient at practically low signal-to-noise ratio regions. Further, we develop a recursive implementation of the total least square algorithm and find it to be slow to converge; for this, we employ a Kalman filter to improve the convergence speed of the total LS method. The resulting total Kalman filter (TKF) is shown to be both unbiased and efficient in ECM identification. The performance of this filter is analyzed using real-world current profiles under fluctuating signal-to-noise ratios. Finally, the applicability of the algorithms and analysis in this article in identifying higher-order electrical ECMs is explained. [ABSTRACT FROM AUTHOR]

This article introduces a thermally-compensated magnetic hysteresis model, capable of accurately determining core losses of ferrite materials while accounting for core temperature variations. The employed model is based on permeance-capacitance analogy and it captures the frequency-independent hysteresis effect with the help of the Preisach model. For validation purposes, a 100 kW, 10 kHz realized medium frequency transformer prototype is selected and modeled as a part of a full-bridge LLC resonant converter in a time-domain simulation environment. Conducted simulations show the ability of the thermally-compensated magnetic hysteresis model to impact the generated core losses for core temperatures of up to 120° C. Finally, a temperature-feedback loop within the transformer is successfully closed inside of a system-level simulation, allowing for a more precise determination of the core and winding steady-state temperatures. [ABSTRACT FROM AUTHOR]

The electrical quality assurance (ELQA) of the superconducting circuits of CERN's Large Hadron Collider (LHC) during its second Long Shutdown (LS2) requires the execution of vast measurement campaigns. Each of 1658 electrical circuits as well as the instrumentation of each of the 1746 individual cryo-assemblies housing magnets, bus-bars and other components of the superconducting circuits, has to undergo a series of tests. At the beginning of the shutdown the tests are performed before and after the warm-up from cryogenic temperatures. The same tests are repeated at the end of the shutdown, this time before and after the cool-down. As part of the dipole bypass diode insulation consolidation project and due to the replacement of a few non-conform magnets, additional electrical tests and measurements had to be performed throughout the shutdown period. With each measurement, electrical parameters like resistance, complex impedance, and the quality of the insulation are verified and stored for future reference. Due to the many thousands of measurements to be performed, multiple automated mobile test benches had to be developed for the different test types along with dedicated database and analysis software applications for the documentation and follow-up of the test results and the non-conformities observed. [ABSTRACT FROM AUTHOR]

The most detailed, first-principle simulation model of a quench in a high-temperature superconducting metal-insulation multi-module/multi-double-pancake coil, wound with a REBCO coated superconductor/tape and normal-metal tape (co-wind), was developed. It enables one to simulate a normal zone propagation, or non-propagation, in the subtle multi-turn structure of the coil's pancakes due to the inductive coupling and transverse electric contact between all the REBCO turns and co-wind turns along with the external circuit and active and passive quench protection systems. In doing so, the multi-module coil's structure is represented as a “rectilinear equivalent” electric circuit, a branched multi-decker multi-rectangle planar grid, which facilitates the mathematical formulation, using the standard electric circuit differential equations and the Kirchhoff's rules. The transient non-linear comprehensive heat conduction equations are employed to model the thermal part of the phenomenon at the same level of detail. All this turns the model into an effective design tool for metal-insulated, -stabilized and/or -reinforced multi-module coils. A parametric study of quench in a 6-module no-insulation (NI) test coil, using a stainless-steel thin co-wind, was conducted to identify the possibilities of the model. The profound effect of the transverse contact resistivity on an NI-coil quench behavior is confirmed and detailed. [ABSTRACT FROM AUTHOR]

High temperature superconductors (HTS) are discussed as energy-efficient solutions for industrial high-current applications beyond 10 kA e.g., bus bar systems in industrial electrolysis plants. In this contribution, the experimental test of a 3.6-meter-long 35 kA DC demonstrator, made from twelve high-current HTS CrossConductor (HTS CroCo) strands in an liquid nitrogen bath at T = 77 K is presented. In this work, a common connector concept of the twelve HTS CroCo strands is proposed. Compared to earlier results without common connector, lead resistances were effectively reduced and current distribution among the individual strands was significantly facilitated. This is confirmed by the observation of increased critical cable current of 37.6 kA compared to 33 kA in previous work without low-resistive common connector. Additionally, the current range, in which all twelve strands reached their critical electric field, was found to be reduced from >7 kA to 2 kA. Results are discussed and assessed with the help of an electric circuit model, from which the solder resistances at the connections could be obtained by fitting. Particular focus was given to the investigation of current redistribution in the demonstrator. Therefore, a heater was installed on one HTS CroCo strand, and activated to raise the temperature on this strand and quench a single strand locally. It is observed that current is redistributed through the common connectors to the other strands. [ABSTRACT FROM AUTHOR]

This paper analyses the current distribution in no-insulation (NI) coils in a layer-wound configuration. The investigation aims at comparing the electrical characteristic of two coils wound from the same BSCCO tape, with or without electrical insulation between turns. Both coils are characterized by a very similar geometry, with the same number of turns and layers. Both coils, cooled in liquid nitrogen bath, are charged until the tape critical current is exceeded. To interpret the measurements and analyze the current distribution within the winding, a lumped-parameter equivalent electrical circuit is developed and solved numerically in a time-varying regime. The model results are compared with the signals acquired through voltage taps soldered at the same locations in both coils. Finally, the model is applied to investigate the impact of the transverse contact resistance and to estimate the most stressed locations of the coil during charging, in terms of power produced by Joule effect. [ABSTRACT FROM AUTHOR]

This article presents a novel hardware-efficient battery balancing circuit for electric vehicle batteries that uses the low-voltage battery as a convenient source and sink for balancing. Compared to existing techniques, the proposed topology strikes a balance between the current industry standard of passive balancing and high component-count, high-cost solutions. For a battery pack consisting of n cells in series within m modules, the proposed design uses (n +1) bilateral switches for cell selection, and m low-voltage isolated dc/dc converters for cell balancing. Balancing can occur quickly during driving as the circuit can transfer energy between nonadjacent cells concurrently throughout the pack. This article presents the design, control, simulation results, and experimental results of the proposed architecture. Furthermore, system-level vehicle modeling shows an increase in driving range of 1.8%–20.1% for different balancing parameters on repeated Urban Dynamometer Driving Schedule and Highway Fuel Economy Driving Schedule cycles for an end-of-life pack, compared to passive balancing, which does not charge cells while driving. [ABSTRACT FROM AUTHOR]

The compact size and high wavelength-selectivity of microring resonators (MRs) enable photonic networks-on-chip (PNoCs) to utilize dense-wavelength-division-multiplexing (DWDM) in their photonic waveguides, and as a result, attain high bandwidth on-chip data transfers. Unfortunately, a hardware Trojan (HT) in a PNoC can manipulate the electrical driving circuit of its MRs to cause the MRs to snoop data from the neighboring wavelength channels in a shared photonic waveguide, which introduces a serious security threat. This article presents a framework that utilizes process variation-based authentication signatures along with architecture-level enhancements to protect against data-snooping HT during unicast as well as multicast transfers in PNoCs. The evaluation results indicate that our framework can improve hardware security across various PNoC architectures with minimal overheads of up to 14.2% in average latency and of up to 14.6% in energy-delay-product (EDP). [ABSTRACT FROM AUTHOR]

A second-order analytic extension of eigenvalue (AEE) method is presented and investigated for efficiently computing the Z- parameters of passive RF circuits over a wide frequency band with full-wave accuracy. The Z - parameters of an RF circuit are first extracted based on a full-wave simulation on sampling frequencies and then decomposed into eigenmodes, whose eigenvalues are analytically extended to all other frequencies within the frequency band of interest based on functional equations constructed from second-order series and parallel RLC circuits. An eigenvector-eigenvalue identity is adopted to compute the frequency-dependent eigenvectors from the eigenvalues of the submatrices, which are used in the expansion of the Z - parameters. A comparison with full-wave solutions is given for the second-order AEE where four frequencies are employed to accurately approximate the Z - parameters and predict the frequency response over the entire band of interest that goes to much higher frequencies than the first-order AEE. With this, the previously developed first-order AEE for a quasi-static analysis is successfully extended to much higher frequencies. Numerical examples are provided to validate the accuracy and demonstrate the capability of the second-order AEE. It is found that the second-order AEE is very accurate for modeling RF circuits with electrical sizes up to one wavelength that possibly contains resonances, as compared to the first-order AEE, which is applicable only to RF circuits with electrical sizes smaller than one-tenth to one-fifth of a wavelength that contains no resonance. [ABSTRACT FROM AUTHOR]

Partial shading is an important subject for the research community to improve the issues in the field of solar array utilization. Shading decreases the life of photovoltaic array, its output power yield, and also generates several peaks in its P–V characteristic curves. Physical relocation of panels can be used as a practical solution to prevent such problems by altering the location of panels but not its electrical circuit. In this article, a reconfiguration technique for all conventional configurations like, series-parallel, bridge-link, honey comb, and total cross tied connections are proposed to reduce current difference between the rows and to improve the irradiance equalization by dispersing the shade. This article proposes a mathematical Tom-Tom puzzle pattern for $5\times 5$ array to enhance the output parameters. The performance of all configurations is evaluated with artificially generated shading to resemble moving clouds which are incremented progressively in row-wise and diagonal manner. From the extensive analysis of results, it has been found that the proposed reconfigurations show better performance than its respective static configurations. The proposed configuration is also tested in terms of income generated and a comparison with the existing state-of-art methods to show the supremacy of the proposed approach. [ABSTRACT FROM AUTHOR]

In this study, a 3-D dispensing method for nonconductive and conductive adhesives is introduced that allows for direct electrical functionalization of the printed part during the printing process. The experimental work’s focus lies on the analysis of the embedding of conductive tracks within nonconductive housings. Two different construction strategies have been analyzed for printing tracks in both xy- and z-directions. For all variants, initial feasibility tests were performed that successfully validated the general applicability of these techniques. As dissimilar materials are involved in the process, a micrograph analysis was used to investigate possible negative effects within the transitional areas. Although prototypical parts can be built easily with additive manufacturing methods, the lack of knowledge about the long-term robustness is often the limiting factor to end-use applications. Accelerated life tests in the form of thermal shock and humidity testing were performed to investigate this issue. The tests demonstrate good long-term behavior for two of four adhesives. The obtained results show that the proposed method and process variants are capable of producing electronically functional parts, provided a careful material selection has been performed. Furthermore, several design rules concerning the transitional area could be derived. [ABSTRACT FROM AUTHOR]

Nowadays, finite element method is the most accurate approach to study an electrical machine. However, its use in an optimization process remains often unsuitable because it can still require prohibitive calculation times. An analytical approach would then be more adapted but it should be as accurate as possible. In the case of an analytical model of a squirrel cage induction machine, currents induced in the rotor bars constitute quantities that are difficult to obtain. The equivalent electrical circuit to use should be well adapted and each of its elements has to be accurately estimated. In this article, an equivalent circuit based on bar lumped parameters is proposed and their identification is detailed. The proposed approach is validated through the comparisons of simulation results with the ones obtained by classical FEA in the case of two examples of squirrel cage induction machines with distributed and concentrated armature windings. [ABSTRACT FROM AUTHOR]

Practical superconducting quantum interference devices (SQUIDs) have been developed into multiloop hybrid electric circuits with Josephson junctions and normal elements such as resistor, inductor and capacitor. To find a common circuit analysis and simulation method for different types of SQUID hybrid circuits consist of both superconducting and normal components, we introduce a mesh-current method, which can derive both the general system model and uniform circuit equations directly from the equivalent circuit. The mesh-current method is demonstrated in the simulation of a SQUID additional positive feedback circuit. The numerical simulation results are presented and verified with the measurements. Compared with the conventional nodal analysis method, the mesh-current method is excellent in dealing with the relations including external flux, self and mutual inductances in multiloop hybrid circuit analysis; its final circuit equations directly exhibit the physical theorems; its general system model reveals the quantum interference mechanism inside SQUID circuits, and is applicable for further dynamics studies. [ABSTRACT FROM AUTHOR]