Search Results (481)

Machine-learning surrogates can accelerate transistor design, but optimized predictions require physical consistency and explicit treatment of surrogate uncertainty. Here, we develop an uncertainty-aware machine-learning framework for compact-model-based design of WSe₂ p-channel field-effect transistors using an experimentally calibrated S2DS model. A 5000-device dataset spanning channel length, equivalent oxide thickness, hole mobility, contact resistance, impurity density, trap density, and gate-voltage offset was used to train a censor-aware neural-network surrogate for full p-branch transfer-curve prediction at two drain biases. On an independent 750-device test set, the surrogate achieved a mean pointwise $R^{2 }$ of 0.9891 and an exact-coordinate RMSE of 0.0799 decade. The framework further combined inverse-identifiability analysis, Sobol sensitivity analysis, and multiobjective optimization of saturation on-state current, saturation-bias maximum transconductance, normalized drain-bias threshold shift, and threshold-voltage placement. Screening of 262,144 candidate designs yielded 48 Pareto-optimal solutions, of which nine satisfied the uncertainty-screening criteria and six retained all four performance claims after direct S2DS reevaluation. These results demonstrate a physically grounded and uncertainty-aware approach for efficient WSe₂ transistor design within an experimentally calibrated compact-model domain. Full article

To address severe transmission signal attenuation caused by inter-phase electromagnetic coupling in three-phase cross-bonded cables, which significantly limits the identification of insulation defects and fault types, this paper proposes a broadband impedance spectroscopy differential-frequency decoupling and defect diagnosis method based on three-phase high-frequency, high-voltage coordinated excitation. First, a decoupled transmission line model for three-phase cross-bonded cables is established to systematically analyze how the degree of insulation damage and fault equivalent impedance affect the frequency domain response at the test terminal. Three core diagnostic parameters, namely the fundamental resonant peak amplitude variation ratio, the resonant period change rate, and the initial phase offset, are extracted to construct a multi-dimensional collaborative diagnosis model for accurate defect and fault identification. Second, a high-voltage topology based on proportional optical isolation driving is designed to overcome the gain and bandwidth trade-off of conventional power amplifiers, effectively mitigating excessive high-frequency signal attenuation and low signal-to-noise ratios in long-distance transmission lines. Using this topology, a three-phase differential-frequency coordinated excitation test platform is developed to ensure the accurate, synchronous injection of isolated three-phase differential-frequency sinusoidal waveforms into the cable sending end. Combined with broadband impedance spectra acquired by the test system, the proposed diagnostic model enables the reliable identification of defect and fault types in three-phase cross-bonded cables, offering practical significance for the safe and stable operation of power transmission systems. Full article

With the increasing penetration of distributed generation, electric vehicles and single-phase loads in the low-voltage distribution network, flexible interconnected systems face more prominent three-phase unbalance and direct-current (DC)-side voltage regulation problems. Unbalanced loads not only lead to asymmetry of alternating current (AC)-side voltage and current but also introduce low-frequency ripples into the common DC bus through the power-coupling relationship and further cause the neutral-point potential shift of the split capacitors. To address these problems, this paper takes a double-ended flexible interconnection system with an integrated three-level Buck–Boost energy storage interface as the research object and proposes a DC-side total-voltage-neutral-point cooperative control strategy. Firstly, the coupling relationship between AC-side power fluctuation and DC-side voltage state under unbalanced conditions is established to analyze the formation mechanism of DC bus low-frequency ripple and neutral-point potential offset; secondly, based on the neutral-point access characteristic of three-level Buck–Boost, the DC-side modulation quantity is decomposed into a common-mode duty cycle and a differential-mode duty cycle. Among them, the common-mode duty cycle is used to regulate the total power exchange on the energy storage side to achieve DC bus total voltage maintenance and low-frequency ripple suppression; the differential-mode duty cycle is used to regulate the difference between the duty cycles of the upper and lower half-bridges to achieve capacitor charging and discharging distribution regulation and neutral-point potential balance. Finally, a simulation model is built to verify the proposed control strategy. The simulation results show that the proposed method is able to stabilize the DC bus voltage around 800 V under power step disturbance and suppress the midpoint voltage deviation from a low-frequency oscillation of about 10 V to within about ±1 V. This verifies the effectiveness of the control strategy under unbalanced load and power disturbance conditions. Full article

The efficacy of low-carbon power systems is reduced by the high energy demand of conventional CO₂ capture processes, the loss of recoverable thermal energy, and power-quality disturbances associated with variable renewable generation. This study suggests an integrated framework that integrates membrane-assisted CO₂ capture, thermoelectric waste-heat recovery, photovoltaic generation, battery energy storage, and a grid-connected converter to address these issues. During the capture of CO₂, the waste heat is converted into electrical energy using a thermoelectric generator and integrated with the photovoltaic and battery outputs through a common DC link. A conventional phase-locked loop is not necessary for reference-signal extraction, DC-offset rejection, harmonic compensation, and power management, as an Enhanced Notch Filter-Based Second-Order Generalized Integrator (ENF-SOGI) controller is employed. The effectiveness of the proposed system is demonstrated by simulation and experimental studies conducted under variable irradiance, nonlinear loading, distorted-load, and distorted-grid-voltage conditions. The membrane unit achieves a CO₂ capture efficiency of approximately 92%, with a specific energy consumption of 1.2 GJ/tCO₂. The controller reduces the source-current total harmonic distortion from 24.3% to approximately 1.2–1.3%, limits its experimental variation to ±5 V, and maintains the DC-link voltage at approximately 600 V. Consequently, the proposed architecture is designed to facilitate low-carbon grid operation by integrating a unified energy-management system that includes high-efficiency CO₂ separation, the productive recovery of waste heat from the capture process, increased renewable energy utilization, and IEEE-compliant source-current quality. Full article

Accurate state-of-charge (SOC) estimation is essential for range prediction, power allocation, and operational safety in electric vehicles. Low-temperature operation introduces coupled effects of capacity degradation and polarization dynamics, which challenge conventional fixed-capacity models and single-timescale estimation methods. This paper proposes a hierarchical multi-timescale SOC estimation framework that combines data-driven capacity prediction, online parameter identification, and nonlinear state estimation. At the upper layer, a temperature-aware temporal self-attention long short-term memory network (TS-LSTM) estimates the available battery capacity. At the lower layer, forgetting-factor recursive least squares (FFRLS) and a gain-scheduled unscented Kalman filter (UKF) jointly track impedance variations and recursively estimate SOC. The framework is validated on public lithium-ion battery datasets at 4, 24, and 43 °C under pulse and sparse high-current conditions. Under the challenging 4 °C scenario with a 10% initial SOC bias, the method achieves an SOC root mean square error (RMSE) of 1.35%. Additional perturbation tests yield SOC RMSEs of 1.35–2.40% under −5% to +10% initial-SOC offsets, 1 mV voltage noise, a +2 °C temperature bias, and a +20% impedance-prior error. Furthermore, the computational overhead remains substantially lower than the data sampling interval, indicating promising potential for online estimation in battery management systems. Full article

A low-profile inverted ridged-waveguide slot array antenna with asymmetric feed is proposed for two-dimensional (2D) wide-angle scanning spaceborne synthetic aperture radar (SAR) applications. The inverted ridge and asymmetric feed structure enables broad-wall radiating slots without lateral offset, achieving an ultra-low profile of 0.28λ₀, significantly lower than typical ridged-waveguide slot arrays for 2D wide-angle scanning applications, while supporting a compact inter-element decoupling configuration. H-shaped slots are further introduced to enhance the structural robustness of large-scale lightweight phased arrays without radiation performance degradation. The fabricated antenna element attains a wide relative bandwidth of 23.16% in the X-band. In array operation, the active voltage standing wave ratio (VSWR) remains below 2.0, and the phased array achieves 2D beam scanning coverage of ±55° in elevation and ±15° in azimuth. Full article

Adder neural networks remove multiplication from convolution, yet their direct L1-distance datapath still requires subtraction, absolute-value generation, and wide accumulation. We address this cost by mapping the online L1 operation to minimum selection and time-domain accumulation. The proposed accelerator processes a $3\times 3\times 16$ window for 16 output channels with 6-bit weights and activations. Each 6-bit minimum is divided into two 3-bit slices. A dual-mode digital-to-time converter (DM-DTC) encodes the most-significant slice in high-linearity (HL) mode and the least-significant slice in low-power (LP) mode. Readout is performed by a shared-clock time-to-digital converter (SC-TDC), in which one Gray-code time reference serves all paths while local latches preserve independent channel results. The training model reproduces code-dependent DTC nonlinearity, process–voltage–temperature variation, jitter, channel offset, TDC quantization, saturation, and scale mismatch. The architecture thereby combines significance-aware time encoding, channel-scalable readout, and hardware-aware adaptation. Post-layout simulations in 55 nm show that the 0.359 mm², 13.7 Kb design operates at 0.7–1.2 V and 5–30 MHz, consumes 0.025–0.324 mW, and achieves 43.2–94.3 TOPS/W. The normalized figure of merit is 6.01–13.09 POPS/W·bit². On CIFAR-10/ResNet-20, hardware errors reduce the baseline accuracy from 92.71% to 86.26%; error-aware training achieves 91.53%. Full article

This study presents a full polymer piezoelectric flextensional energy harvester (FPPFEH) comprising a single-layer poly(vinylidene fluoride) (PVDF) film bonded to a 3D-printed polylactic acid (PLA) flextensional frame. For an arm inclination angle of $\theta =10°$, the free-body model gives a theoretical geometric force-amplification factor of $M_{\mathrm{F}}=\cot \theta \approx 5.67$; this value represents an ideal upper bound and was not independently validated by local force or strain measurements. During assembly, the film was tensioned only to remove visible slack and maintain a flat configuration. No intentional pretension was applied, and any residual tension was not measured. Off-resonance force-controlled tests showed that the generated voltage was approximately proportional to the dynamic input force and nearly independent of frequency after accounting for attenuation caused by the finite measurement-input impedance. The ideal quasi-static model overpredicted the absolute voltage by a nearly constant factor across the tested force range. This offset is consistent with a lumped reduction associated with frame compliance and the in-plane anisotropy of the PVDF film, neither of which was independently measured. At $30\mathrm{Hz}$ and $12.32{\mathrm{N}}_{\mathrm{rms}}$, the rectified output charged a $6600\mathsf{\mu }\mathrm{F}$ supercapacitor to $2.10\mathrm{V}$ in $14\min$, corresponding to $14.55\mathrm{mJ}$ of stored energy. Under base-acceleration excitation from $0.05$ g to 1 g, the voltage peak occurred between $112.88$ and $116.49\mathrm{Hz}$, close to the electrical anti-resonance near $114\mathrm{Hz}$, and reached $12.11{\mathrm{V}}_{\mathrm{peak}}$ at 1 g. Near resonance, the highest measured power among the tested resistive loads occurred between 150 and $200\mathrm{k}\Omega$; however, the exact optimal resistance could not be resolved from the four tested loads. These results demonstrate off-resonance force-driven energy storage and resonance-mode vibration energy harvesting within the tested conditions. Full article

Ensuring the safety and reliability of photovoltaic (PV) installations requires accurate electrical arc fault detection. This work presents a computational arc fault detection framework that combines fixed-length windowing, Fast Fourier Transform (FFT)-based features, and supervised machine learning classifiers. Data were acquired using an Arc Fault Circuit Interrupter (AFCI) test bench developed based on IEC 63027. Current and voltage signals were partitioned into 200-sample windows, DC-offset corrected, and Hann-windowed signals. Each window generated 204 statistical and spectral attributes used to train and evaluate Random Forest (RF), K-Nearest Neighbors (KNN), Multilayer Perceptron (MLP), and Convolutional Neural Network (CNN) models. Hyperparameters were tuned by grid search with TimeSeriesSplit cross-validation, comparing min–max normalization and Z–Score standardization. On a 15% hold-out test set, CNN with Z–Score achieved F1 = 0.9982 and recall = 0.9975, followed by MLP (F1 = 0.9957) and RF (F1 = 0.9821). Amortized per-window inference latencies were ≈0.0035 ms for RF, ≈0.0016 ms for MLP with Z–Score, and ≈0.032 ms for CNN. These classifier-stage timings indicate computational compatibility with edge-oriented implementation but do not constitute an end-to-end IEC 63027 AFCI compliance assessment. The framework targets integration into PV inverters at Mackenzie Presbyterian University’s solar plant. Full article

This paper proposes a single-stage common-ground series-capacitor-compensated buck–boost inverter (CG-SCC-BBI) for wide-input DC–AC applications. Featuring a common-ground neutral and a series-blocking film capacitor, the topology inherently suppresses high-frequency common-mode leakage-current excitation and blocks the structural DC offset. To counteract frequency-dependent voltage attenuation caused by the output network, a fundamental-frequency equivalent model is derived to pre-scale the modulation reference and fully restore output voltage amplitude. The four-switch power stage operates with single-active-leg PWM, confining high-frequency switching to a single half-bridge at any instant to significantly reduce the switching-loss budget. Furthermore, by eliminating the conventional line-frequency output filter choke and utilizing film capacitors exclusively, the topology completely avoids electrolytic capacitors, thereby enhancing long-term operational reliability and lifespan. The proposed inverter supports seamless transition between boost and buck operating modes across the entire input-voltage range. Its operating principles are validated through time-domain simulations, and these were experimentally verified on a 300 W SiC MOSFET standalone laboratory prototype. Experimental results confirm correct operation from 95 V to 400 V DC input, achieving maximum measured efficiencies of 96.79% at the rated 300 W under low-input operation and 97.66% at the rated 300 W under high-input operation, while maintaining an output-current total harmonic distortion (THD) below 2.5%. Full article

Converter-dominated power systems increasingly require flexible resources that can support frequency while preserving a physically interpretable energy trajectory. Thermal-energy-storage (TES)-based virtual energy storage systems (VESSs) can shift electrical demand within thermal-energy and comfort constraints, and have therefore attracted extensive interest. However, existing studies commonly coordinate requested or normalized power without fully connecting it to actuator execution and the electrical-to-thermal energy path. Command-level sharing cannot be directly equated with executed physical power, and controller storage cannot be combined with joule-valued hardware energy without dimensional separation. Therefore, this paper proposes a physically coupled and energy-traceable virtual asynchronous machine (VAM) control method for TES-based VESSs. First, a loss-resolved averaged model establishes the point-of-common-coupling (PCC)–converter–DC-link–actuator–TES physical chain and separates the hardware Hamiltonian from the dimensionless control Lyapunov function. Second, a neighbor-coupled marginal controller is embedded in a command–projection–execution chain so that frequency regulation and weighted sharing are evaluated using the executed service. Third, a constraint-handling mechanism combines directional headroom gating, actuator saturation and ramp limits, thermal comfort bounds, and request-inactive state reset to maintain executable trajectories under the declared constraints. Simulations under a sustained $120\mathrm{kW}$ disturbance show that primary-only control retains a $-0.08883\mathrm{Hz}$ steady-state offset, whereas the proposed nominal case restores frequency. In the constrained case, the 30 s terminal trend remains above the prescribed limit, while both terminal windows of the 60 s run satisfy the restoration criterion; the final-window mean error and dimensionless eligible-unit sharing spread are $-6.317\times {10}^{-5}\mathrm{Hz}$ and $6.564\times {10}^{-5}$, respectively. The model-internal electrical–thermal balance achieves a dimensionless relative RMS residual of $6.2361\times {10}^{-8}$. Because the PCC voltage/current pair is reconstructed from the same power source, this residual quantifies model-internal consistency rather than independent measured closure. These results demonstrate constrained frequency restoration, executed-power coordination, and energy traceability within the averaged-model scope. Full article

Electrohydrodynamic emission from a sessile droplet depends on a coupled balance among electric traction, capillarity, gravity, charge transport and liquid motion. The present work addresses only the electrostatic-loading part of that problem. Verification-backed axisymmetric and three-dimensional Laplace solvers are used to map how parallel-plate, on-axis-pin, off-axis-pin and bipolar double-pin electrodes redistribute the normal electric field over a prescribed conducting water-droplet interface. The primary response is the dimensionless electric capillary number, Ca_E = ε₀E_n²R_v/γ. To compare geometries on a common voltage scale, V₁ is defined as the applied voltage at which the peak prescribed-interface loading reaches Ca_E = 1. V₁ is a normalisation voltage and not a jetting or stability threshold. The axisymmetric solver reproduces the exact conducting-hemisphere solution to within 0.07% at the finest grid. The three-dimensional finite-difference results are mesh-assessed, and their normalised surface-field topology is cross-checked against an independently implemented Galerkin finite-element model. At 4 kV, the finite parallel-plate cell produces an apex enhancement of 3.24 relative to V/H. Replacing the plate with an on-axis 1 mm pin reduces the apex field by 39.5%, which corresponds to a 63% reduction in Ca_E, and increases V₁ from approximately 5.0 to 8.2 kV. Lateral pin displacement moves the surface-field maximum away from the apex and produces a broad nominal plateau near d = 5–7 mm, although the sub-grid steering distance remains sensitive to mesh and extraction settings. The bipolar double-pin configuration produces two symmetric surface-field maxima together with a near-null at the apex. This topology, but not its absolute magnitude, is reproduced by the finite-element cross-check. A Gaussian-process model interpolates the one-dimensional offset family accurately under leave-one-offset-out validation (R² = 0.999). Four Bayesian-optimisation trials locate the broad steering plateau but show no visible evaluation-count advantage over random sampling in this one-dimensional test. A three-mesh study gives a reported field-magnitude mesh-sensitivity estimate of approximately 6.2% at the finest grid (rising to about 9.5% at the h = 0.20 mm production mesh) for the representative three-dimensional case, and an indicative combined-uncertainty band of approximately 10% is shown for V₁ in the exploratory trade-off plot. Illustrative Young–Laplace profiles at contact angles of 70° to 110° preserve the comparative pin-versus-plate field reduction, whereas V₁ varies by up to approximately 50%. A simplified Peek-law screening estimate places corona inception (the pin being cathodic) in the approximate range of 4.8–10 kV, which is comparable to the on-axis-pin V₁, so gas discharge may intervene before large electrocapillary loading is reached in ambient air. The results establish electrode geometry as a controllable electrostatic-loading parameter while explicitly deferring coupled stability analysis and experimental validation. By resolving this loading on a single exact-solution-verified basis, the study quantifies electrode geometry as a control parameter that idealised enhancement factors and the nominal gap field cannot capture and provides a verified fixed-interface reference state for subsequent coupled electrohydrodynamic modelling. Full article

The escalating penetration of distributed photovoltaic (PV) systems has intensified grid-connected voltage violations, posing severe challenges to the stability of distribution networks. This paper first investigates the mechanisms of voltage violations at 35 kV substations and 380 V consumer-side terminals under high-penetration scenarios. It is demonstrated that PV integration elevates line voltage, with the voltage profile at any given node being governed by the equivalent net load—defined as the offset between total demand and PV generation—downstream of that node. Subsequently, the impacts of critical operating conditions, including PV penetration levels, line impedance, and dynamic meteorological variations, are quantitatively analyzed. Simulation results characterize voltage fluctuation patterns under diverse variables, such as varying PV outputs, line parameters, and interconnection points, thereby validating the theoretical derivation. Finally, an integrated management strategy, coupling coordinated reactor compensation with voltage-source inverter (VSI) control, is proposed. Simulation results across multi-dimensional complex scenarios verify the effectiveness of the proposed strategy in suppressing voltage violations and enhancing grid resilience. Full article

The problem of fault diagnosis in electrical motors has an important impact on the supervision of dynamic systems, and model-based methods are efficient tools for this purpose. In this regard, this work presents a novel method for detecting inter-turn short circuits (ITSCs) in the stator windings of permanent magnet synchronous motors (PMSMs). The approach is based on algebraic identification to process the motor voltage signals, estimating the offsets, amplitudes, and phases of the fundamental and third-harmonic components. Fault detection is performed in two steps: first, a voltage imbalance index is evaluated to determine the presence of abnormal operating conditions. Subsequently, characteristic patterns in the estimated parameters are analyzed to identify both the fault type and the affected phase(s). The experimental results show that single-phase ITSC faults produce a reduction in the offset of the faulted phase together with an increase in its third-harmonic amplitude, whereas phase-to-phase ITSC faults lead to an increase in the offsets of the affected phases and nearly identical third-harmonic amplitudes between them. In both cases, only minor variations are observed in the estimated phase angles. The effectiveness of the proposed methodology is supported through theoretical analysis and validated experimentally using voltage measurements acquired from a PMSM test bench. The results demonstrate that the proposed technique can accurately identify fault conditions through voltage imbalance and harmonic-pattern analysis, providing a practical and computationally efficient methodology for PMSM stator winding fault diagnosis. Full article

Organic solar cells (OSCs) are a potential photovoltaic technology because they can be manufactured in scalable systems, are lightweight, and have mechanical flexibility. Power conversion efficiencies close to 20% have been achieved in recent years due to the quick development of donor–acceptor material systems. Better control over nanoscale shape and the creation of non-fullerene acceptors are major factors driving this advancement. Nevertheless, there are still complicated connections between morphology, interfacial energetics, and molecular structure. It is yet unclear how these elements interact to affect charge creation and transport. In this review, donor–acceptor interactions in organic solar cells are examined from a fundamental chemical and physical perspective. From conventional fullerene derivatives to contemporary non-fullerene acceptors, we first look at the development of acceptor materials. We demonstrate how molecular engineering has enhanced device efficiency, energy level adjustment, and light absorption. We then examine the energetic alignment at donor–acceptor interfaces, paying particular attention to charge-transfer state creation, border orbital offsets, and the factors influencing voltage losses. We also investigate how intermolecular interactions, including hydrogen bonding, π-π stacking, and noncovalent interactions involving heteroatoms, control electrical coupling and nanoscale shape in bulk heterojunction active layers. We also go over device engineering techniques including processor control, interface engineering, and bulk heterojunction architecture optimization. These tactics demonstrate how improved solar performance might result from molecular design. Lastly, we highlight new possibilities for next-generation OSCs, such as scalable production techniques, adaptive molecular design, and morphological stabilization. This work provides a strong framework for comprehending donor–acceptor interactions and for directing the careful design of high-performance organic photovoltaic systems by combining knowledge from molecular chemistry, morphological control, and device engineering. Full article