Search Results (117)

Power electronic converters play an important role in proton exchange membrane (PEM) electrolyzers, where current ripple has been associated with electrode potential fluctuations, electrocatalyst degradation, and long-term system durability. This paper presents a unified analytical framework for multicell interleaved Buck DC-DC converters with parallel switching arms intended for low-ripple operation in electrochemical energy conversion systems. Existing steady-state analytical models are generally topology-specific and require new derivations for different converter configurations, limiting scalability and design flexibility. The proposed formulation considers a converter composed of k interleaved cells and M parallel switching arms per cell, resulting in a generalized converter architecture where the total number of switching devices is n = kM. Closed-form expressions are derived for the DC voltage gain, inductor current ripple, electrolyzer voltage ripple, and capacitor RMS current. The analysis shows that ripple cancellation and ripple-frequency multiplication are governed by the operating-region distribution and the total number of switching devices. In addition, normalized closed-form expressions are developed to establish scalable ripple-oriented design charts applicable to arbitrary converter configurations. By enabling the identification of operating conditions that minimize current ripple, the proposed methodology provides practical guidelines for the design of power converters supplying PEM electrolyzers and other catalyst-based electrochemical energy conversion systems. Consequently, the proposed model contributes to the development of power electronic interfaces that mitigate electrical stress on electrocatalysts, supporting improved durability and reliability of electrochemical energy conversion systems. Full article

Gene regulatory networks (GRNs) describe regulatory interactions between transcription factors and their target genes and are essential for understanding cellular processes and disease mechanisms. Recent advances in single-cell RNA sequencing (scRNA-seq) have enabled data-driven GRN inference at single-cell resolution. However, the high sparsity and noise inherent in scRNA-seq data pose substantial challenges for accurately recovering regulatory relationships. Existing graph neural network (GNN)-based approaches often rely on localized message passing, which can lead to over-smoothing and limited modeling of long-range regulatory dependencies. To address these limitations, a structure-aware interleaved-attention graph learning framework, termed IAGRN, is proposed for GRN inference from scRNA-seq data. Specifically, it interleaves topology-constrained local attention with distance-aware global attention, enabling effective integration of structural priors and long-range regulatory signals. Graph Laplacian positional encoding is further incorporated to preserve topological information and enhance node representations. Evaluations on seven public benchmark datasets demonstrate that IAGRN consistently improves GRN reconstruction under highly sparse conditions and achieves competitive performance compared with existing approaches. Full article

Proton exchange membrane fuel cell (PEMFC) systems typically generate low-voltage and high-current DC power, requiring a step-up converter interface for electric vehicle (EV) and DC microgrid applications. In addition, excessive current ripple and rapid transient loading conditions may increase electrical and thermal stress within the fuel cell stack. Consequently, both converter topology and control strategy play important roles in maintaining stable system operation and favorable PEMFC operating conditions. This paper presents a differential flatness-based nonlinear control strategy for a PEMFC-fed multiphase interleaved boost converter. The proposed control structure combines inner-loop inductor current regulation with outer-loop DC bus energy regulation. This configuration achieves stable voltage control, balanced phase-current sharing, and reduced fuel cell current ripple during transient operating conditions. A two-phase interleaved boost converter prototype was experimentally implemented using a 2.5 kW PEMFC platform and a dSPACE DS1202 MicroLabBox real-time controller. Experimental tests under steady-state and dynamic loading conditions were conducted to evaluate DC bus voltage regulation, transient response, current-sharing capability, and robustness against load disturbances. The experimental results demonstrated that the proposed nonlinear controller achieved faster transient voltage recovery and smaller DC bus voltage deviation compared with a conventional PI-based control approach. In addition, the interleaved converter structure reduced input current ripple at the PEMFC output terminals during dynamic operation. Overall, the results indicate that the proposed control strategy is suitable for PEMFC-powered EV and DC microgrid applications requiring stable DC bus regulation and fast dynamic power control. Experimental results demonstrate that the proposed controller reduces the DC bus voltage recovery time from approximately 150 ms to 50 ms, corresponding to a 66.7% improvement over a conventionally tuned PI controller. In addition, the maximum DC bus voltage deviation is reduced from approximately 1.0 V to 0.5 V while maintaining balanced phase-current sharing with less than 3% mismatch throughout the tested operating conditions. Full article

This study evaluates a fixed Kronecker-sequence interleaver under controlled synthetic three-dimensional correlated-fault models. Spatial-cluster, column-correlated, and bit-plane-dependent probability fields are used as coding-level abstractions and are not calibrated device measurements. The K-IPA mapping is compared with random, structured 3D block, modular-stride, and length-adapted quadratic-permutation-polynomial (QPP-style) mappings using BCH(63,45) and RS(63,45) backends. At p = 0.015 and ρ = 0.85, K-IPA BCH has lower FER than random, 3D block, and QPP-style BCH, but its difference from stride BCH is small, and the paired confidence interval includes zero. Within the RS backend, the paired comparisons among K-IPA, stride, and QPP-style mappings do not resolve a difference at this operating point. Because the BCH and RS tensor partitions contain different numbers and types of decoder units, their FER values are not used to rank the two code families. The topology study further shows that no fixed mapping is uniformly best. A separate address-remapping implementation check verifies the fixed lookup table only; device-calibrated fault validation and complete codec hardware evaluation are outside the evidence provided here. Full article

The intensive development of electric vehicle (EV) technology, renewable energy systems, and stationary energy storage solutions has amplified the demand for advanced Battery Management Systems (BMS). The imbalance in cells within lithium-ion battery packs, due to manufacturing tolerances, varying aging, and thermal gradients, reduces available capacity, cycle life, and can cause thermal runaway. Active charge equalization with DC–DC converters has become a recent research focus among various balancing techniques because it has a better capability of redistributing energy. This paper gives a detailed study of converter-based cell-balancing topologies with a specific focus on the bidirectional flyback converter and the interleaved two-phase variant. Non-isolated topologies (buck–boost, Cuk converter topology, interleaved buck–boost) and isolated topologies (flyback, push–pull, dual-active bridge, LLC resonant) are compared concerning functional efficiency, component reduction, galvanic isolation, scalability, and bidirectional capability. The concept of soft-switching, including zero-voltage switching (ZVS) and zero-current switching (ZCS), and their circuit realizations are discussed. Advanced control models and artificial intelligence (AI) for the estimation of state-of-charge (SoC) and real-time optimization are mentioned. Thermal issues, scalability, reliability, and wide-bandgap semiconductor devices (SiC/GaN) are discussed. Full article

This paper presents an energy-recovering active snubber in which the energy captured by the snubber capacitor is transferred back to the converter’s input using an auxiliary inverting switching stage. The snubber operates independently of the main power stage and can therefore be applied to a wide range of isolated converter topologies without modifying their primary control or structure. The proposed snubber achieves an energy-recovery efficiency of approximately 80%, thereby reducing snubber-related losses by the same proportion. As a representative implementation, the concept was experimentally validated in a 550 W dual-phase interleaved DC–DC flyback converter, where it improves the overall converter efficiency by 1.6 percentage points and reduces total losses by 18% compared with a dissipative snubber solution. The proposed snubber supports a wide input-voltage range and is well suited for multiphase converters, as most of its components can be shared between phases. Full article

Future More-Electric and All-Electric Aircraft (MEA/AEA) require electric power systems (EPS) with higher installed power, improved reliability, and reduced complexity, motivating a fundamental reshape of the architecture and key system-level design choices. This paper applies a structured design process to future DC-based EPS and derives justified decisions from a comprehensive assessment of state-of-the-art research. Among three possible topologies, the bipolar three-wire DC grid is selected as the preferred architecture due to its superior corona suppression, insulation behavior, electromagnetic compatibility, safety, and reliability. A voltage-level study shows that increasing the low-voltage bus from 28 V to 48 V yields the most significant wiring-weight reduction (∼20%), while increasing the high-voltage level from 800 V to 1200 V offers only marginal benefits and introduces additional insulation and partial-discharge challenges. For power conversion, both isolated and non-isolated DC/DC converters are required: non-isolated multiphase interleaved converters are suited for smaller subnetworks, whereas isolated dual active bridge converters are foreseen for inter-grid power exchange. Midpoint grounding via a resistor is identified as a robust baseline concept that ensures fault detectability and operational continuity while providing controlled fault currents and limited voltage deviations, with the final resistance value to be refined based on the finalized grid configuration. The study focuses on architecture-level assessment and does not include dynamic simulations or experimental validation, which are identified as areas for future work. Full article

The manipulation of vector beams (VBs) with longitudinally variant polarization states is an important research topic and has potential applications in classical and quantum fields. In this study, we propose a half-wave plate dielectric metasurface composed of two interleaved sub-metasurfaces to generate longitudinally separated dual-channel vectorial structured light fields. The propagation and Pancharatnam–Berry phases are employed to construct hyperbolic, helical, and opposite gradient phases for focusing wavefronts, generating circularly polarized (CP) vortices, and deflecting CP vortices with the same chirality in opposite directions. Consequently, dual-channel higher-order or hybrid-order Poincaré (HOP or HyOP) beams are generated along the optical axis under elliptically polarized illumination, and their polarization states evolve along an arbitrary pair of antipodal meridians on the HOP or HyOP sphere by varying the ellipticity of the incident light, the propagation-phase topological charge, and the rotation order of the meta-atom. The consistency between the theoretical and simulated results demonstrates the feasibility and practicability of the proposed method. This study is significant for compact, integrated, and multifunctional optical devices, and provides an innovative strategy to extend optical field manipulation from two-dimensional to three-dimensional space. Full article

Electric vehicle (EV) chargers play an important role in the popularity of electric vehicles. In order to improve the efficiency of EV chargers, this paper replaces the discrete inductors in an interleaved Boost PFC topology with a coupled inductor. Theoretical analysis of the Boost PFC topology was presented, and the coupled inductor was designed, with simulation verification. Experimental testing of the designed coupled inductor was done on a 7 kW EV charger platform. The experimental results show that the designed coupled inductor can improve the efficiency of an EV charger. Full article

This paper proposes a single-stage three-phase AC-DC converter based on an LLC resonant topology utilizing a front-end matrix switch. Unlike traditional two-stage solutions, the proposed topology synthesizes a fluctuating equivalent DC voltage from the three-phase input, achieving direct power conversion with high efficiency. To maintain a stable DC output voltage against the time-varying input, a trajectory-based Pulse Frequency Modulation (PFM) control strategy is developed. By employing State-Plane Analysis (SPA), the operational trajectory is divided into four calculation segments, allowing precise derivation of the switching frequency and duty cycles for both boost and buck modes within a single line cycle. Furthermore, to improve power density and reduce parasitic parameters, a high-frequency planar inductor with interleaved windings and a planar transformer are designed for 500 kHz operation. A pipeline control architecture based on a single DSP is implemented to handle the complex real-time computations. A 500 W prototype is built and tested under 100 V input and 130 V output conditions. Experimental results demonstrate that the converter achieves a peak efficiency of 97%, a power factor of 0.99, and a grid current Total Harmonic Distortion (THD) of 3.95%, validating the effectiveness of the proposed topology and control scheme. Full article

In this paper, a coupled-inductor-based interleaved Buck converter is presented. By employing a negatively coupled inductor, the proposed topology reduces magnetic component number and improves dynamic response. Operating in boundary conduction mode (BCM), the proposed converter can achieve zero-voltage switching (ZVS) under a wide voltage and load range. The control strategy is fully digital, allowing the switching frequency to be adaptively adjusted without the need for a zero-crossing detection (ZCD) circuit. Furthermore, an optimal coupling coefficient design is proposed, which minimizes the frequency adjustment range. In addition, the design process for a coupled inductor with an interleaved winding structure is introduced in detail. Finally, a 300 W experimental prototype is built, the experimental results of which demonstrate its effectiveness and feasibility. Full article

Reliable Internet connectivity is essential for latency-sensitive services such as video conferencing, media streaming, and online gaming. Round-trip time (RTT) is a key indicator of network performance and is central to setting retransmission timeout (RTO); inaccurate RTT estimates may trigger unnecessary retransmissions or slow loss recovery. This paper proposes an Enhanced Regularized Extreme Learning Machine (RELM) for RTT estimation that improves generalization and efficiency by interleaving a bidirectional log-step heuristic to select the regularization constant C. Unlike manual tuning or fixed-range grid search, the proposed heuristic explores C on a logarithmic scale in both directions ($\times 10$ and /10) within a single loop and terminates using a tolerance–patience criterion, reducing redundant evaluations without requiring predefined bounds. A custom RTT dataset is generated using Mininet with a dumbbell topology under controlled delay injections (1–1000 ms), yielding 1000 supervised samples derived from 100,000 raw RTT measurements. Experiments follow a strict train/validation/test split (6:1:3) with training-only standardization/normalization and validation-only hyperparameter selection. On the controlled Mininet dataset, the best configuration (ReLU, 150 hidden neurons, $C={10}^2$) achieves $R^2=0.9999$, $MAPE=0.0018$, $MAE=966.04$, and $RMSE=1589.64$ on the test set, while maintaining millisecond-level runtime. Under the same evaluation pipeline, the proposed method demonstrates competitive performance compared to common regression baselines (SVR, GAM, Decision Tree, KNN, Random Forest, GBDT, and ELM), while maintaining lower computational overhead within the controlled simulation setting. To assess practical robustness, an additional evaluation on a public real-world WiFi RSS–RTT dataset shows near-meter accuracy in LOS and mixed LOS/NLOS scenarios, while performance degrades markedly under dominant NLOS conditions, reflecting physical-channel limitations rather than model instability. These results demonstrate the feasibility of the Enhanced RELM and motivate further validation on operational networks with packet loss, jitter, and path variability. Full article

A fast modelling framework is presented for loss estimation in current-source microinverters. The power stage is modelled with ideal switches and simplified magnetics to keep simulations lightweight, while dedicated estimators reconstruct core, conduction, and switching losses from simulated waveforms using Steinmetz-based and analytical models. The method is demonstrated on an interleaved active-clamp flyback with H-bridge unfolder but remains topology-agnostic and applicable to other current source (CS) DC/DC variants. Control includes maximum power point tracking (MPPT) with voltage-reference tracking, a PID loop, simplified grid synchronization, and peak-current regulation. Dynamic tests under irradiance and grid-voltage variations confirm stable operation and correct MPPT behaviour. A steady-state loss breakdown at 0.75 p.u. irradiance predicts ~97% overall efficiency, consistent with reported microinverter performance. The framework enables rapid design exploration and efficiency prediction without full device-level modelling, balancing accuracy and computational speed. Full article

Against the backdrop of rapid advances in computing, industry, and electric vehicles, DC–DC buck converters—as core point-of-load regulators—are critical for power supplies in applications with stringent voltage-stability requirements. This paper proposes a two-phase interleaved Buck converter based on positively coupled inductor with a high coupling coefficient. The innovation lies in the positively coupled inductor and two-phase interleaved architecture, where two MOSFETs and two diodes form a similar symmetrical full-bridge interleaved structures together achieve a higher conversion ratio and provide $ZCS$ operation for all power devices, thereby effectively reducing switching losses. Relative to traditional topologies, the proposed converter delivers a higher conversion ratio without extreme duty-cycle operation while improving reliability. After detailing the operating mechanism, we derive the input–output voltage relation, outline controller synthesis guidelines, and specify the soft-switching conditions. From the viewpoint of symmetry, the proposed interleaved converter exploits the electrical and magnetic symmetry between phases to achieve current balancing, extended duty-cycle range and soft-switching. Validation is provided by both a $PSIM$ simulation model and a $270W$ hardware prototype using an $STM32F103ZET6$, which achieves 93.3% peak efficiency at a conversion ratio of 0.45, demonstrating the practicality and effectiveness of the approach. Full article

This paper presents a high-efficiency bidirectional multidevice interleaved SEPIC–ZETA DC–DC converter for electric mobility applications. The proposed converter offers key advantages, including reduced current and voltage ripple at both the input and output ports, achieved through a port ripple frequency six times higher than the switching frequency. Additionally, the required magnetic and capacitor volume is significantly reduced due to an inductor ripple frequency twice the switching frequency, leading to minimized power losses, reduced stress on power components, and enhanced efficiency. The use of a multidevice structure facilitates more efficient inductor volume optimization and provides improved fault redundancy. The converter is particularly suited for electric vehicle energy management systems, enabling efficient energy management among the various subsystems. It operates in open-loop mode, and this manuscript details the steady-state operating principle under continuous conduction mode. Design guidelines for parameter selection, comprehensive mathematical derivations, and a comparative analysis with existing DC-DC converters are presented. To validate the proposed topology, a 5 kW laboratory prototype was developed and tested across a wide range of load conditions. The experimental results confirm the converter’s high performance, achieving a peak efficiency of 98.6% at rated power. Full article