Search Results (2,572)

Constant-current/constant-voltage (CC/CV) charging requires an inductive power transfer (IPT) converter to maintain the desired output characteristic and high efficiency over a wide range of operating-point load conditions. To address this challenge, this paper proposes a multimode reconfigurable IPT topology for high-power wireless charging of automated guided vehicles (AGVs). The topology coordinates reconfiguration between LCC–LCC and LCC–S compensation networks with full-bridge/half-bridge operation on both the inverter and rectifier sides, establishing three operating modes for low-load CC, higher-load CC, and high-load CV charging without a cascaded output DC–DC converter. A hybrid mode-switching strategy is further developed: the Mode 1/2 boundary is selected at the equal-efficiency point to preserve wide-range efficiency, whereas the Mode 2/3 boundary is selected at the equal-power point to reduce the CC-to-CV transition-power discontinuity. Experimental results obtained with resistive load banks over 3–144 Ω show that the hybrid strategy maintains a measured power-stage DC–DC efficiency of 91.72–94.95%. Compared with fixed single-mode operation over the same range, the hybrid strategy increases the minimum measured efficiency from 85.70% to 91.72%, an improvement of 6.02 percentage points. The prototype achieves a maximum output power of 15.26 kW at 94.71% efficiency, demonstrating the feasibility of the proposed reconfigurable approach for high-power, wide-load-range AGV wireless charging. Full article

Shipboard DC power systems increasingly employ battery energy storage systems to buffer load fluctuations, support DC bus stability, and improve power supply continuity. Accordingly, the isolated DC–DC converter interfacing the battery with the shipboard DC bus must achieve both high conversion efficiency and low battery-side current ripple. However, LLC resonant tank parameters simultaneously affect conversion losses, soft-switching characteristics, and ripple transmission, while the frequency-dependent battery impedance cannot be accurately represented by a conventional resistive load model. This paper therefore proposes a multi-objective resonant parameter optimization framework that jointly considers conversion efficiency and battery-side high-frequency current ripple. A unified converter–battery mechanistic model is established using the fundamental harmonic approximation and impedance network analysis, from which a computable battery-side ripple-current metric is derived. Multi-objective particle swarm optimization is then applied to generate a Pareto-optimal solution set and identify efficiency-oriented, ripple-oriented, and compromise designs. Experimental results obtained from a laboratory prototype verify the predicted efficiency and ripple trends, demonstrating that the proposed framework provides practical guidance for LLC resonant parameter selection in shipboard battery energy storage interfaces. Full article

ALK rearrangements define an important molecular subtype of lung adenocarcinoma, and the rearranged ALK serves as a well-established oncogenic driver in this malignancy. The most common type of mutation is the EML4-ALK fusion. Meanwhile, rare fusions are also frequently discovered with regard to ALK. However, clinical efficacy varies substantially across rare ALK fusion variants due to their distinct biological features, and individualized drug selection guided by fusion architecture and tumor characteristics is therefore required. This case presents the entire treatment process of a female patient with advanced lung adenocarcinoma who had an OSBPL9-ALK fusion. The patient was diagnosed in early 2021; by referring to previous reports and model prediction with AlphaFold 2 and Autodock Pymol, the new second-generation ALK inhibitor Ensartinib was chosen. After 24 months, due to disease progression, she switched to the third-generation ALK inhibitor, Lorlatinib, after model prediction. After 15 months, for further disease progression, the anti-angiogenic drug, anlotinib, was added to the treatment plan. Unfortunately, 6 months later, the disease progressed further, and the patient chose supportive treatment for economic reason. Nine months later, the patient died. The presentation of this case will provide a reference guideline for the subsequent treatment of lung adenocarcinoma with the same fusion. Meanwhile, model-based prediction for ALK fusion targeted therapy can provide a predictive reference for drug selection in patients presenting similar ALK rearrangements in the future. Full article

Compared with conventional two-coil wireless power transfer (WPT) systems, three-coil WPT systems with an intermediate relay coil offer superior performance in terms of transmission distance and tuning flexibility, making them suitable for a wider range of applications. To address the CC/CV hybrid charging challenge in practical three-coil wireless power transfer (WPT) systems, based on the dual-frequency compensation network (DFCN), this paper proposes a dual-frequency switchable LCC-S-S and S-S-S compensated three-coil topology along with a systematic parameter tuning methodology. Furthermore, the proposed system exhibits zero-phase angle (ZPA) input impedance characteristics at both resonant frequencies, and the ZPA condition remains invariant under coupling coefficient variations. Unlike conventional approaches requiring additional active components, such as relays or AC switches, the proposed compensation topology realizes simple and efficient CC/CV hybrid charging by only switching between two resonant frequencies. An experimental prototype rated at 400 W is constructed to assess the efficacy of the presented framework. The system has a simple structure, is easy to control, and has stable output. The peak DC-DC efficiency reaches 92.15% and 92.75% in both the CC and CV charging modes, respectively. Full article

Sliding mode control (SMC) is widely recognized for its robustness against modeling uncertainties and external disturbances. However, asymmetric actuator dynamics, excessive switching activity, and the absence of active cooling challenge its application to electric heating systems. This paper proposes a Model-Assisted Dual-Adaptive Parameter Adjustment Sliding-Mode Controller (DAPA-SMC) for PWM-based temperature control of an electric furnace. The proposed controller combines a nominal model-based heating component with an adaptive sliding-mode correction and simultaneously adjusts the switching gain and boundary-layer width using a unified adaptation indicator derived from the sliding variable. Hysteresis-based operating-mode logic, together with an adaptive cooling attenuation mechanism, explicitly addresses the asymmetric heating and passive-cooling characteristics of thermal processes. The controller output is directly interpreted as a PWM duty cycle, enabling straightforward implementation in industrial programmable logic controllers (PLCs). The proposed approach is evaluated through both simulation and experimental validation on a laboratory bell-type electric furnace and compared with a conventional clipped SMC and a model-assisted fixed-parameter SMC. Simulation results demonstrate improved transient performance and substantially reduced duty-cycle variation. Experimental results confirm comparable temperature regulation performance, while the control total variation is reduced to 7.61, compared with 57.72 for the conventional SMC and 66.57 for the MA-SMC, corresponding to reductions of 86.8% and 88.6%, respectively. This smoother commanded duty cycle is accompanied by 587 recorded binary PWM transitions, compared with 365 and 345 for the two reference controllers. Furthermore, reducing the cooling attenuation parameter from $\mu =0.06$ to $\mu =0.02$ decreases the experimental cooling undershoot from 29.33 °C to 21.22 °C for the $500\to 400 °$C transition and from 22.64 °C to 14.09 °C for the $400\to 300 °$C transition, corresponding to reductions of 27.7% and 37.8%, respectively, without materially changing the overall tracking performance. The proposed DAPA-SMC provides a computationally simple control architecture that can be implemented directly on an industrial PLC and offers a practical approach to PWM-based temperature control of thermal processes with asymmetric heating and passive-cooling dynamics. Full article

This paper proposes a type of converter suitable for switched reluctance generators (SRGs) with a new construction. The new topology of the converter does not require capacitors on the DC bus side and performs AC-AC conversion directly by controlling the generator through phase-to-phase voltage. It can reduce the capacitor charging structure, lower maintenance costs, reduce the impact of speed variations on interphase voltage, and enhance excitation. The paper will discuss in detail the working principle and characteristics of the proposed converter, and finally, it will verify the effectiveness of the proposed method based on the simulation results. Simulation results demonstrate the feasibility of the proposed topology for the generator application: the three-phase excitation currents reach a peak value of approximately 120 A, and the phase-to-phase voltage is maintained within the range of approximately 100 V under the simulated operating condition, with stable waveforms and no evident distortion, confirming that the proposed new converter can reliably drive the SRG. Full article

The ±500 kV valve halls of wind farm offshore platforms are integrated through a high-voltage direct current (HVDC) transmission system and constructed in deep-sea conditions, making the design of net air clearance distances particularly critical. This paper investigates key factors influencing air clearance distances associated with the impulse overvoltage characteristics of the main equipment in the valve hall. Based on the preliminary design of a ±500 kV offshore converter valve hall, critical air gaps were determined. The full-scale samples were employed to conduct standard switching impulse overvoltage tests. In this way, the overvoltage discharge characteristics of air gaps in the offshore converter valve hall were obtained. Finally, based on the air gap configuration method and the obtained discharge characteristic data, a recommended net air clearance distance range is proposed for the ±500 kV valve hall of the offshore platform, providing a vital reference for the compact design of offshore wind farm valve halls. Full article

This paper studies a nonlinear system of switched fractional differential equations with generalized Caputo fractional derivatives with respect to another function. The main characteristics of these fractional derivatives are twofold: the lower limit of the fractional derivative equals the switching time, and the applied function in the fractional derivative changes in each interval between two consecutive switching times. Several comparison results and some results for the fractional derivative of convex Lyapunov functions are obtained. Also, strict stability of the zero solution is defined and sufficient conditions for strict stability of the system are obtained. The auxiliary results allow us to avoid the application of fractional derivatives of convex Lyapunov functions in our sufficient conditions. The conditions depend significantly on the type of switching rule and the switching points. Full article

To address receiver-side weight constraints, resonance detuning, and output-current variations caused by coil misalignment in unmanned aerial vehicle (UAV) wireless charging, this paper proposes an inductive power transfer system employing an inductor-series/none (L-S/N) compensation topology and primary-side-sensing-based constant-current control. The topology eliminates the secondary compensation network, while its tuning conditions and constant-current characteristics are derived using a T-network immittance-inverter model. The mutual inductance is identified from two primary-current magnitude measurements without secondary-side sensing or wireless communication. A switched capacitor controlled by pulse-width modulation (PWM) is then used to restore resonance, and inverter phase-shift control compensates for the output-gain variation caused by changes in mutual inductance. In addition, a three-layer stacked magnetic coupler is designed to improve mutual-inductance stability under horizontal misalignment. Experimental results demonstrate stable operation at different misalignment positions, achieving a DC-to-DC efficiency of 84.3% at an output power of approximately 98 W. Full article

Financial markets exhibit complex nonlinear dynamics driven by interactions between firm-specific characteristics and macroeconomic conditions, requiring robust mathematical models capable of capturing structural changes and temporal heterogeneity. This study proposes an explainable machine learning framework that combines regime-switching analysis and predictive modeling to investigate the long-term resilience of firms listed in the BIST 100 Index. Structural breaks in monthly return and volatility series are first detected using the Pruned Exact Linear Time (PELT) algorithm, enabling the classification of firm trajectories into resilient and fragile market regimes. A Regime Persistence Score is then introduced to quantify the proportion of time each firm remains in the resilient state. This score serves as the response variable in a Random Forest model that evaluates the influence of firm-specific financial indicators and macroeconomic variables, including exchange rates, producer price inflation, and commercial loan interest rates. In addition, a forward-looking classification model estimates the probability that firms will transition into a fragile regime within the subsequent six months. The proposed framework achieves an AUC of 0.706 and demonstrates stable predictive performance under alternative regime definitions, penalty parameters, cost functions, and cross-validation strategies. Explainability analysis derived from Shapley Additive Explanations (SHAP) data shows book-to-market ratio and sensitivities to inflation and interest rate changes as the most important components of enduring resilience. The proposed methodology provides an interpretable mathematical framework for regime detection, nonlinear time-series modeling, and decision support in sustainable financial systems, offering practical value for risk assessment and resilience-oriented portfolio management. Full article

Background/Objectives: Confidence is typically studied in simple perceptual decisions, although everyday decisions also require cognitive control and monitoring of action. Across two experiments, we examined whether response conflict, stimulus complexity, and sequence affect task performance and retrospective metacognitive judgments concerning different aspects of performance: confidence in response correctness and confidence that a covert partial error occurred. Methods: Participants performed a modified Stroop task in which they responded to word colour and, in compound trials, also reported the position of an accompanying line. In Experiment 1 (N = 66), participants rated confidence in the correctness of their responses. In Experiment 2 (N = 47), electromyography was used to identify covert partial errors, and participants rated confidence that a partial error had occurred. Results: Conflict reduced response accuracy, prolonged response times, and was associated with a small reduction in confidence in correct responses. In Experiment 1, the effect of sequence on confidence depended on stimulus complexity: confidence was higher in simple-repeated than in simple-switched trials, whereas the opposite pattern was observed for compound trials. In Experiment 2, partial errors occurred more frequently under conflict but less frequently in compound trials. Greater incorrect-burst surface and longer correction time were associated with higher partial-error confidence, and both relationships were weaker in compound trials. The association with incorrect-burst surface remained reliable after adjustment for response time. Exploratory analyses also showed lower metacognitive sensitivity under conflict and complexity and lower metacognitive efficiency in compound trials. Conclusions: Cognitive-control demands were associated with retrospective metacognitive judgments concerning both completed response outcomes and partial-error events occurring during response generation. Conflict was associated with a small reduction in confidence in correct responses, whereas partial-error confidence was associated with measurable characteristics of the partial-error event. The weaker relationship between EMG-derived response-process characteristics and confidence during compound processing suggests that current task demands affect how strongly internal response-related information is related to metacognitive judgments. Full article

To mitigate capital investment costs, the multi-to-one configuration, wherein multiple alkaline electrolyzers share a single balance of plant (BoP) system, is widely adopted in projects. However, compared with the one-to-one configuration, the strong coupling inherent in the shared BoP imposes complex mutual constraints on the on-off switching and load allocation of multiple electrolyzers, thereby compromising the operational flexibility of the hydrogen plant. To leverage the complementary strengths of multi-to-one and one-to-one configurations regarding investment costs and operational flexibility, this paper proposes a mixed configuration method for multi-to-one electrolyzers in solar power-to-hydrogen systems. First, the hydrogen production characteristics, on-off switching, and power allocation of multiple alkaline electrolyzers are modeled. Furthermore, the coupling constraints specific to multi-to-one clusters are characterized based on practical engineering experience. Subsequently, a mixed configuration model targeting the minimization of the levelized cost of hydrogen (LCOH) is proposed. This problem is formulated as a mixed-integer fractional programming (MIFP) model with second-order cone constraints. Meanwhile, the information gap decision theory (IGDT) is applied to address photovoltaic power output uncertainty, and a bounded Dinkelbach algorithm is employed to reduce computational complexity. Case studies based on a real-world project in northern China demonstrate that the proposed mixed configuration model reduces the LCOH by 0.6%, 0.7%, and 1.3%, respectively, compared to uniform four-to-one, two-to-one, and one-to-one configurations. Additionally, the robustness analysis based on the IGDT demonstrates that the mixed configuration achieves the largest tolerable PV uncertainty radius under the prescribed LCOH limits. Full article

To improve the dc-bus voltage utilization while reducing the commutation burden of an insulated gate bipolar transistor (IGBT)-based open-end winding permanent magnet synchronous motor (OEW-PMSM) drive, this paper proposes an improved alternate sub-hexagonal center PWM (ASHCPWM) strategy. The drive employs two three-phase IGBT inverters sharing a common dc bus. Since the turn-off energy of an IGBT is strongly affected by its switching frequency, ASHCPWM alternately clamps one inverter and reduces the number of switching transitions. The resulting common-mode voltage mismatch, together with the dead-time voltage error required to prevent shoot-through in the IGBT bridge legs, nevertheless produces significant zero-sequence current and additional semiconductor current stress. A mathematical model of the zero-sequence voltage is therefore established, and a common-mode voltage compensation method is combined with an improved Kalman-filter-based harmonic extraction and closed-loop suppression strategy. The switching performance of the modulation is evaluated by counting the switching transitions of the twelve IGBTs and by comparing the zero-sequence current and phase-current spectra. Experiments on a 10 kHz prototype demonstrate that the proposed method substantially reduces zero-sequence harmonics while retaining the reduced-switching characteristic of the original ASHCPWM. Full article

Owing to its favorable physical and chemical characteristics, zinc oxide (ZnO) has become one of the most extensively investigated metal oxide semiconductors. Pulsed laser irradiation in liquids provides a post-synthesis route for modifying ZnO nanostructures. However, correlating laser parameters with the systematic evolution of particle morphology, size distribution, and surface chemistry remains challenging. In this work, a facile and additive-free pulsed laser irradiation approach was employed to engineer the morphology and surface chemical composition of ZnO nanoparticles. As-prepared hydrothermally synthesized ZnO nanorods dispersed in deionized water were irradiated with a Q-switched Nd:YAG laser for 30 and 90 min and compared against the untreated powder. TEM and SEM analyses revealed a progressive morphological transformation in which the strongly agglomerated, faceted nanorods partially reshape into a mixed rod and particle morphology after 30 min and evolve into well-dispersed, nearly spherical nanoparticles with diameters of approximately 12–48 nm after 90 min. XRD confirmed that the hexagonal wurtzite structure is retained throughout the treatment with no secondary or impurity phases, while the mean crystallite size increases from 15.14 nm for the powder to 18.80 nm after 90 min of irradiation as a result of photothermal fusion. XPS demonstrated that zinc preserves its +2 oxidation state during laser processing, whereas the surface O/Zn ratio and the relative fractions of lattice oxygen and hydroxyl species evolve systematically with irradiation time, revealing a concurrent modification of the surface chemistry. These results establish the laser post-irradiation duration as a simple and effective control parameter for tailoring both the morphology and surface chemical state of ZnO nanostructures. Full article

We study nonlinear stochastic dynamical systems that evolve in a Markov environment with separated fast and slow transition scales. These systems are also subject to impulsive perturbations under a Poisson approximation scheme. The environment is represented on a product state space, and phase aggregation is used to average the rapidly switching component while retaining the slower Markov regime explicitly. Under the stated ergodicity, regularity, integrability, tightness, state-preservation, and uniqueness assumptions, we derive an effective reduced process and establish weak convergence of both the impulsive component and the coupled nonlinear system in the Skorokhod space. The limiting jump dynamics are characterized by averaged local characteristics associated with the retained slow Markov regime. To assess the reduced model numerically, we use a nonlinear competitive Lotka–Volterra-type system and compare the deterministic dynamics, the full Markov-switching stochastic model, and the reduced approximation under several fixed parameter configurations and jump-intensity settings. The results provide a mathematical basis for the reduced modeling of nonlinear stochastic dynamical systems with separated Markov time scales and impulsive perturbations. Full article