Search Results (88)

Wireless power transfer (WPT) technology, leveraging the unique advantage of contactless power supply, has been recognized as a core power supply solution for mobile devices such as automated guided vehicles (AGVs) and electric vehicles (EVs). However, its transmission performance is highly susceptible to lateral offset, longitudinal misalignment, and angular deflection of the coils, resulting in a sharp decline in efficiency and unstable output. This has become a key bottleneck restricting the engineering application of the technology. This paper presents a comprehensive review focusing on the misalignment tolerance technologies for WPT systems. First, taking the LCC-S/LCC topology as an example, the influence of coil misalignment on the system output performance is analyzed, and various misalignment tolerance methods are enumerated. Subsequently, the basic principles and main research achievements of four categories of misalignment tolerance technologies, namely coupling structure optimization, compensation topology optimization, control strategies, and alignment guidance technology, are systematically summarized, with their limitations identified. Finally, the future research directions of misalignment tolerance technologies are discussed. Full article

This paper presents the design and calculation of wireless power transfer (WPT) integrated with the Hamiltonian Control Law. The proposed controller demonstrates greater effectiveness in terms of system stability and precise energy control, as compared to the commonly used PI controller in industrial applications. The proposed prototype has been built for assessment in both simulation and implementation, with a rated output power of 500 W and 48 V. The load-independent compensating topology, such as the LCC-S resonant tank, is used to transmit power wirelessly through an air core. Finally, in the last stage, the Hamiltonian Control Law with state observer is applied on the dc-to-dc buck mode converter to control the battery current and overall system. Apparently, the charging current can be precisely regulated to a specific value. Full article

Wireless power transfer is gaining attention in medium-to-short-range applications such as 1–3 kW-class UAVs and AGVs due to its safety, reliability, and adaptability to complex environments. The LCC-S topology is widely adopted due to its favorable output characteristics and device voltage-stress distribution. However, under fixed coil parameters and operating frequencies, conventional LCC-S achieves high efficiency only near the optimal equivalent load. When the actual load deviates from this value—especially in heavy-load regions—resonant cavity current increases sharply, voltage gain drops significantly, and overall efficiency deteriorates. To overcome this structural limitation without increasing control complexity or adding active regulation stages, this paper proposes a transformer-assisted LCC-S wireless charging topology based on “equivalent load reconstruction.” First, a unified equivalent circuit is constructed to derive analytical expressions for voltage gain, input impedance, and efficiency under arbitrary coupling coefficients and loads for both the traditional LCC-S and the proposed topology, revealing the mechanism behind efficiency degradation under heavy loads. Building upon this foundation, a high-frequency transformer is introduced, with an efficiency-oriented collaborative design method for its turns ratio and excitation inductance. Furthermore, by integrating simplified copper and iron-loss models, the losses in the resonant cavity and the transformer are decomposed and evaluated. Results demonstrate that when transformer parameters are appropriately selected, the newly introduced transformer losses are significantly smaller than the resonant cavity losses reduced through load reconstruction. The constructed 1 kW, 85 kHz prototype demonstrates that within the 0.5–2.5 Ω load range, the proposed topology achieves efficiency exceeding 88%. Under typical heavy-load conditions, its peak efficiency surpasses that of the conventional LCC-S by approximately 20%. The theoretical analysis, simulation, and experimental results are highly consistent, verifying that the transformer-assisted LCC-S topology and its efficiency-oriented design method can effectively expand the high-efficiency operating range across a wide load spectrum without altering the control strategy. This provides a concise and feasible structural optimization solution for wireless charging systems. Full article

To address the issue that the output voltage and power of medium- and low-power wireless power transfer (WPT) systems cannot remain constant under coil misalignment, this paper proposes a single-switch WPT system with misalignment-tolerant characteristics. Based on a single-switch topology, the system combines the LCC-S and S-S compensation networks through an input-series and output-series connection, forming a simplified hybrid-compensated single-switch WPT topology. By exploiting the complementary output characteristics of the two compensation networks, a stable output voltage is achieved under varying mutual inductance conditions. To further enhance misalignment adaptability, a grid-type flat spiral (GFSP) coil is designed for the magnetic coupler. This coil configuration avoids magnetic flux cancelation during lateral displacement, while maintaining a consistent mutual inductance variation trend between the dual windings, thereby exhibiting strong tolerance to misalignment along the X-axis. The proposed system is validated through MATLAB/Simulink simulations and experiments on a 50 W prototype. The results demonstrate that the system maintains resonance and achieves zero-voltage switching (ZVS) of the power device under ±60 mm X-axis misalignment, with output voltage fluctuation below 4% and efficiency fluctuation below 3%, verifying the proposed system’s effectiveness in misalignment tolerance. Full article

To enhance the battery endurance of unmanned aerial vehicles (UAVs), this article addresses key issues in traditional wireless power transfer (WPT) systems. These issues occur during constant current/constant voltage (CC/CV) switching, such as poor stability, high payload, power loss, and charging instability. Accordingly, a WPT system based on topology switching is proposed. First, a lightweight compensation topology based on LCC-Series compensated topology (LCC-S) is designed. A tuning capacitor is incorporated, and two switches regulate the switching of the compensation capacitor to realize CC/CV mode transition. Meanwhile, the impedance matrix model is built to find optimal compensation component values, maximizing energy transfer. To reduce sensitivity to misalignment, a “+” shaped compensation coil is added to the basic 2 × 2 square coil array. It improves magnetic field uniformity and suppresses flux leakage. Experimental results show that the system achieves stable load-independent output. Within horizontal offset [−150, 150] mm and diagonal offset [−150√2, 150√2] mm, it keeps output power over 150 W and efficiency over 70%, with strong anti-misalignment ability. This system effectively solves key challenges such as endurance bottlenecks, complex CC/CV switching, and weak anti-misalignment. It offers a reliable technical solution for efficient charging of autonomous UAVs. Full article

Public CVE feeds add tens of thousands of entries each year, overwhelming patch-management capacity. We model the CWE–CVE–CPE triad and, for each CWE, build count-weighted product co-exposure graphs by projecting CVE–CPE links. Because native graphs are highly fragmented, we estimate graph-distance box-counting dimensions component-wise on the fragmented graphs using greedy box covering on unweighted shortest paths, then assess significance on the largest component of reconnected graphs. Significance is evaluated against degree-preserving nulls, reporting null percentiles, a z-score–based p-value, and complementary KS checks. We further characterise meso-scale organisation via normalized rich-club coefficients and k-core structure. Additionally, we quantify percolation sensitivity on the reconnected graphs by contrasting targeted removals with random failures for budgets of 1%, 5%, 10%, and 20%. This quantification involves tracking changes in largest-component size, average shortest-path length on the LCC, and global efficiency, and an amplification factor at 10%. Our corpus covers the MITRE CWE Top 25; we report high-level summaries for all 25 and perform the deepest null-model and sensitivity analyses on a subset of 12 CWEs selected on the basis of CVE volume. This links self-similar topology on native fragments with rich-club/core organisation and disruption sensitivity on reconnections, yielding actionable, vendor/software-type-aware mitigation cues. Structural indices are used descriptively to surface topological hotspots within CWE-conditioned product networks and are interpreted alongside, not in place of, EPSS/KEV/CVSS severity metrics. Full article

Identifying and ranking influential nodes is central to tasks such as targeted immunization, misinformation containment, and resilient design. Structural entropy (SE) offers a principled, community-aware scoring rule, yet the one-shot (static) use of SE may become suboptimal after each intervention, as the residual topology and its modular structure change. We introduce iterative structural entropy (ISE), a simple yet powerful modification that recomputes SE on the residual graph before every removal, thus turning node targeting into a sequential, feedback-driven policy. We evaluate SE and ISE on seven benchmark networks using (i) cumulative structural entropy (CSE), (ii) cumulative sum of largest connected component sizes (LCCs), and (iii) dynamic panels that track average shortest-path length and diameter within the residual LCC together with a near-threshold percolation proxy (expected outbreak size). Across datasets, ISE consistently fragments earlier and more decisively than SE; on the Netscience network, ISE reduces the cumulative LCC size by $43\%$ (RLCCs $=0.567$). In parallel, ISE achieves perfect discriminability (monotonicity $M=1.0$) among positively scored nodes on all benchmarks, while SE and degree-based baselines display method-dependent ties. These results support ISE as a practical, adaptive alternative to static SE when sequential decisions matter, delivering sharper rankings and faster structural degradation under identical measurement protocols. Full article

To address the limitations of conventional magnetically coupled resonant wireless power transfer (MCR-WPT) systems in multi-frequency multi-load applications—specifically inadequate load power independence and high complexity inconstant-voltage/constant-current (CV/CC) control—this paper proposes a variable-structure dual-frequency dual-load wireless power transfer system by first establishing its mathematical model and implementing hybrid-frequency modulation for multi-frequency output, then developing an improved T/LCC hybrid resonant topology by deriving parameter design conditions for compensation network reconfiguration under CV/CC requirements, subsequently employing an orthogonal planar solenoid coupling mechanism and frequency-division demodulation to achieve load-independent power regulation across wide load ranges for enhanced stability, and finally constructing a 120 W dual-frequency dual-load prototype to validate the system’s CV/CC characteristics, where simulations and experimental results demonstrate stronger consistency with theoretical predictions. Full article

Wireless power transfer (WPT) technology offers a convenient, efficient, and environmentally robust power supply solution for rack-and-pinion modules. For WPT systems in such modules where the transmitter coil is a long rail, increasing the transmitter coil turns to enhance mutual inductance leads to issues like high cost, low efficiency, and installation difficulties. This paper introduces a relay resonator to strengthen system coupling and proposes a three-coil design scheme employing a single-turn long rail as the transmitter coil. The proposed all-detuned LCC-S-S topology exhibits constant output voltage (CV) and zero phase angle (ZPA) input characteristics while accounting for all cross-mutual inductances and coil resistances. The frequency detuning level of the relay resonator critically governs the system’s power transfer efficiency and directly determines the operational mode of the rectifier—either continuous conduction mode (CCM) or discontinuous conduction mode (DCM). To maximize system efficiency, the optimal detuning frequency of the relay coil is selected under CCM operation. Through optimized design of the three-coil parameters, the final prototype achieves an output power of 106.743 W and an efficiency of 90.865% when integrated with a 1200 mm single-turn long-rail transmitter coil. Full article

Wireless power transfer (WPT) systems for autonomous underwater vehicles (AUVs) are gaining traction in marine exploration due to their operational convenience, safety, and flexibility. Nevertheless, disturbances from ocean currents and marine organisms frequently induce rotational, axial, and air-gap misalignments, significantly degrading the output power stability. To mitigate this issue, this paper proposes a novel reconfigurable WPT system utilizing coaxial antipodal dual DD (CAD-DD) coils, which strategically switches between a detuned S-LCC topology and a detuned S-S topology at a fixed operating frequency. By characterizing the output power versus the coupling coefficient (P-k) profiles under both reconfiguration modes, a parameter design methodology is developed to ensure stable power delivery across wide coupling variations. Experimental validation using a 1.2 kW AUV charging prototype demonstrates remarkable tolerance to misalignment: ±30° rotation, ±120 mm axial displacement, and 20–50 mm air-gap variation. Within this range, the output power fluctuation is confined to within 5%, while the system efficiency exceeds 85% consistently, peaking at 91.56%. Full article

As the scale of shipboard power systems expands, their vulnerability becomes increasingly prominent. Identifying vulnerable points in ship power grids is essential for enhancing system stability, optimizing overall performance, and ensuring safe navigation. To address this issue, this paper proposes an algorithm based on fuzzy local dimension and topology (FLDT). The algorithm distinguishes contributions from nodes at different radii and within the same radius to a central node using fuzzy sets, and then derives the final importance value of each node by combining the local dimension and topology. Experimental results on nine datasets demonstrate that the FLDT algorithm outperforms degree centrality (DC), closeness centrality (CC), local dimension (LD), fuzzy local dimension (FLD), local link similarity (LLS), and mixed degree decomposition (MDD) algorithms in three metrics: network efficiency (NE), largest connected component (LCC), and monotonicity. Furthermore, in a ship power grid experiment, when 40% of the most important nodes were removed, FLDT caused a network efficiency drop of 99.78% and reduced the LCC to 2.17%, significantly outperforming traditional methods. Additional experiments under topological perturbations—including edge addition, removal, and rewiring—also show that FLDT maintains superior performance, highlighting its robustness to structural changes. This indicates that the FLDT algorithm is more effective in identifying and evaluating vulnerable points and distinguishing nodes with varying levels of importance. Full article

Wireless power transfer systems require not only strong coupling capabilities but also stable output under various misalignment conditions. This paper proposes a hybrid magnetic coupler for autonomous underwater vehicles (AUVs), featuring two identical arc-shaped rectangular transmitting coils and a combination of an arc-shaped rectangular receiving coil and two anti-series connected solenoid coils. The arc-shaped rectangular receiving coil captures the magnetic flux generated by the transmitting coil, which is directed toward the center, while the solenoid coils capture the axial magnetic flux generated by the transmitting coil. The parameters of the proposed magnetic coupler have been optimized to enhance the coupling coefficient and improve the system’s tolerance to misalignments. To verify the feasibility of the proposed magnetic coupler, a 300 W prototype with LCC-S compensation topology is built. Within a 360° rotational misalignment range, the system’s output power maintains around 300 W, with a stable power transmission efficiency of over 92.14%. When axial misalignment of 40 mm occurs, the minimum output power is 282.8 W, and the minimum power transmission efficiency is 91.6%. Full article

To improve the ability of line-commutated converters (LCCs) to resist commutation failure (CF) when a fault occurs on the AC side, a novel sub-module-based LCC topology actively resistant to CF is proposed in this paper. The control strategy and the parameters of the proposed sub-module are elaborately designed. The proposed LCC topology can actively resist CF by providing an auxiliary commutation voltage to the AC side, and the sub-module is conducive to the rapid recovery of the thyristor’s forward blocking ability. Additionally, the initial capacitor voltage of the sub-module is designed optimally based on the commutation mechanism. The proposed LCC system can effectively improve the ability to resist CF by increasing the commutation margin of the LCC system. Furthermore, the capacitors are charged and discharged during fault time, so the capacitor voltages do not drop too low and, thus, are better at resisting CF. Matlab/Simulink simulation results verify that the proposed LCC quickens the commutation process, promotes commutation performance, and enhances the immunity of LCCs to CF. Full article

To address the challenge of a conventional line-commutated converter (LCC), unable to operate properly in connection with a very weak AC system, the technology of the capacitor-commutated converter (CCC) was widely utilized in 1990s. The topology of the CCC is constructed as a conventional LCC modified with a series capacitor between the converter transformer and the thyristor valves in each phase. Additional phase voltage can be generated on the capacitor to assist the process of the commutation. However, the CCC technology may experience continuous commutation failure due to the uncontrolled charging of the series capacitor. Based on the submodule-cascaded static synchronous compensator (STATCOM), this paper proposes a novel topology called the submodule-cascaded STATCOM-based CCC (SCCC). The SCCC technology enables the function of reactive power compensation and active filtering. It can also improve the transient characteristics of the AC faults via dynamic reactive power injection during the transient process, which helps to reduce the risk of continuous commutation failure in the CCC. Full article

This study presents the development, simulation, and hardware implementation of a 48 V, 1 kW mid-range wireless power transfer (WPT) platform for autonomous guided vehicle (AGV) charging in industrial applications. The system uses an LCC-S compensation topology, selected for its ability to maintain a constant output voltage and deliver high efficiency even under load variations at a typical coil distance of 15 cm. It can also operate at different distances by adjusting the compensator circuit. A proportional–integral (PI) controller is implemented for current regulation, offering a practical, low-cost solution well suited to industrial embedded systems. Compared to advanced control strategies, the PI controller provides sufficient accuracy with minimal computational demand, enabling reliable operation in real-world environments. Current adjustment can be dynamically carried out in response to real-time changes and continuously monitored based on the AGV battery’s state of charge (SOC). Simulation and experimental results validate the system’s performance, achieving over 80% efficiency and demonstrating its feasibility for scalable, robust AGV charging in Industry 4.0 Manufacturing Settings. Full article