Permanent magnet propulsion motors are pivotal for the development of more-electric aircraft due to their high power density. This paper focuses on the thermal analysis of an outer-rotor air-cooled hybrid axial transverse flux permanent magnet motor (HATF-PMM), a topology for which temperature evaluation is particularly complex and challenging. In this paper, the thermal resistance network model (TRNM) is utilized to calculate temperature rise characteristics of HATF-PMM in complex aviation environment, which is verified by finite-element model (FEM). Considering the calculating time and accuracy, the TRNM is used to evaluate the temperature safety of the HATF-PMM under complex working conditions and flight altitude. According to the evaluation results, the suitable application of HATF-PMM is summarized. In the end, the analysis results of TRNM and FEM are validated by the prototype experiment, which proves that the proposed TRNM of HATF-PMM has advantages of the rapidity and convenience in temperature analysis and safety evaluation.

For hybrid-electric unmanned aerial vehicles (UAVs), the stable power supply from the onboard permanent magnet synchronous generator (PMSG) is critical. Overheating in the confined compartment can directly lead to power interruption and system failure. Therefore, proactively improving the thermal management is not only a key technical prerequisite for ensuring flight reliability and mission success, but also enhances the machine's efficiency and the overall power density of the system. Targeting the stringent spatial constraints in UAV applications, novel self-air-cooling heat dissipation topologies are investigated and highlighted on the rotor sidewall for compact outer-rotor generators. A systematic optimization framework, centered on a multi-objective genetic algorithm, is developed to Pareto-optimize the fin geometries, balancing thermal performance against aerodynamic penalty. The proposed topologies are innovatively deployed on the rotor sidewall, uniquely combining the structural space of an outer-rotor machine with self-air-cooling to generate directed airflow of varying patterns that directly enhance the cooling efficiency of the stator. The parameters of the designed self-air-cooled heat dissipation topologies are optimized via a multi-objective genetic algorithm. A temperature rise test under windless conditions shows that the proposed self-air-cooled structure reduces the stator temperature of the generator by 37.1 °C at 5000 r/min, confirming the effectiveness and engineering feasibility for practical applications.

While bio-inspired design has significantly advanced the performance of composite laminates and T-joints, its application to stiffened structures remains underdeveloped. To address this gap, this study proposes a novel bio-inspired double-blade composite stiffened structure (Bio-DCSS), emulating the "dense outer and sparse inner" architecture of avian wing bones to mitigate stress concentration at web-flange junctions. A high-fidelity progressive damage model (PDM), integrating a strain-based 3D-Hashin failure criterion, continuum damage mechanics (CDM), and a cohesive zone model (CZM), was developed and validated against experimental data. The results demonstrate that, with a mere 2.09% mass penalty, the Bio-DCSS achieves remarkable improvements over its conventional counterpart: 39.74% in buckling load, 11.50% in ultimate load, 2.94% in pre-buckling stiffness, and 12.45% in post-buckling stiffness. Parametric studies further reveal that the load-bearing capacity is highly sensitive to the position of the Polyvinyl Chloride (PVC) foam. This work provides not only a high-performance bio-inspired solution but also a validated modeling methodology and design insights for the lightweight design of next-generation aerospace structures.

Magnetic screws (MSs) are commonly utilized as crucial components in rotary-linear motion systems, which can be used in vehicle transmission systems with long-term reliability and low-noise. Typically, helical permanent magnets (PMs) are adopted for rotary-linear motion conversion. However, the helical PM topology increases the MS complexity and the cost. Therefore, a field-modulated magnetic screw (FMMS) without helical PMs is investigated with competitive thrust and torque performance in this paper. The operating principle of the relationships between geometric parameters i.e. the starts lines and the lead of the translators, the rotor pole pair number, and the stator pole pitch is derived for the first time. Moreover, it exhibits a complex three-dimensional (3-D) magnetic field, requiring a simplified analytical model for rapid analysis, which is highlighted in this paper. On this basis, the topology of a unit MS is proposed to simplify 3-D finite element analysis (FEA). Meanwhile, a 2-D equivalent model of the unit screw is utilized based on a combination of magnetic reluctance networks and 2-D FEM. By using the 2-D equivalent model, the optimal geometric parameters for FMMS are obtained with the accuracy of the 2-D equivalent model verified through the comparative study with 3-D FEM. Finally, the prototype is built and tested to verify the analytical and 3-D FEM results.

Harmonic current regulation in multi-phase motor drives remains challenging under dynamic operating conditions due to non-sinusoidal back electromotive force (EMF) and inverter nonlinearities, which introduce dominant low-order harmonics. Multi-synchronous reference frame (MSRF) based methods are widely adopted for multi-frequency current regulation; however, conventional implementations typically rely on low-pass filters (LPFs) for harmonic decoupling, introducing detection delay and phase distortion that limit transient performance. This paper proposes an LPF-free MSRF-based harmonic current control method for dual three-phase permanent magnet synchronous motor (DTP-PMSM) drives. By introducing harmonic transformation matrix coefficients (HTMCs), the proposed method retains the independent regulation of multiple harmonic components within the MSRF framework, while eliminating the filtering step in the harmonic decoupling path, without the need for harmonic plane reconstruction or additional coordinate transformations. To support adaptive changes, a Goertzel-based harmonic amplitude extraction scheme is employed to periodically update the HTMC. Experimental results demonstrate that the proposed method significantly enhances dynamic performance, achieving a 19.3% reduction in speed transition stabilization time compared to other methods. The proposed LPF-free formulation provides a practical solution for MSRF-based harmonic current control in industrial motor drive applications where fast dynamic response is required.

Sliding mode control (SMC) is widely used in permanent magnet linear synchronous motor (PMLSM) servo systems. However, improving the antidisturbance performance of SMC requires increasing the control gain, and excessive gain may induce severe sliding mode chattering. To resolve this trade-off, this manuscript proposes an adaptive high-order supercritical sliding mode control (AHOSSMC) method for PMLSM servo systems. By integrating high-order sliding mode control (HOSMC) with an adaptive gain strategy based on control barrier function (CBF), the conflict between disturbance rejection and chattering suppression is effectively mitigated, and the friction force in the PMLSM servo system is better compensated. Both the high-order sliding mode algorithm and the adaptive law are improved to enhance the performance of the AHOSSMC. Moreover, the switching behavior of the adaptive law is explicitly addressed to ensure continuous variation of the adaptive gain. Finally, comprehensive experimental validation is conducted to demonstrate the superior position tracking performance of the proposed AHOSSMC.

As electronic devices advance towards higher performance and miniaturization, the demand for flexible thermal interface materials has significantly increased. Liquid metal (LM) is considered an ideal conductive filler of polymer materials due to its superior thermal properties and fluidity. However, LM's electrical conductivity makes achieving insulation in LM-polymer composites with high LM content challenging. This study introduces a novel method for preparing uniform dispersion, high thermal conductivity yet non-conductive LM composite films. This method involves pre-coating LM microspheres using sodium alginate microcapsule before incorporating them into a polyurethane matrix. This approach effectively overcomes the inherent challenges associated with the uniform distribution of LM in polymers, such as leakage and uneven dispersion, thereby significantly enhancing the stability and filler loading of LM. Even when stretched, the LM microcapsules will not be broken. Through this technique, we successfully increased the LM loading to 80 wt%, while preserving the mechanical integrity and electrical insulation properties of the composite. The thermal conductivity of the composite increased from 0.17 W/mK to 1.59 W/mK, significantly surpassing that of unmodified polyurethane. The electrical resistivity was measured as 1.1 G Omega m under normal conditions and remains high even under 300 % elongation. Furthermore, the surface properties of the composite have been investigated, revealing that its hydrophobicity decreased as the microcapsule content increased. This study adeptly achieves a synergistic balance between high filler loading and the enhancement of thermal, electrical, and mechanical properties, making it ideal for the demanding specifications of high-performance electronics and advanced energy systems.

Under extreme weather events represented by severe convective weather (SCW), the adaptability of power system and service restoration have become paramount. To this end, this paper presents a novel planning method of stationary-mobile integrated battery energy storage system (SMI-BESS) capable of spatial flexibility. This designed system can flexibly switch between stationary and mobile modes to cope with normal operation and extreme weather events. Considering the multitude of threats posed of SCW, such as extreme wind speed, lightning strikes, and hail, a comprehensive fragility model of the distribution network is established to quantify adverse impacts of the extreme event. Uncertainties in renewable energy generation and distribution network failures are characterized using two types of ambiguity sets. A two-stage adaptive distributionally robust optimization (2S-ADRO) model is developed to plan the SMI-BESS in detail, meeting the requirements of mobile energy storage. Finally, case studies are conducted using weather and grid data from some regions in China to validate the effectiveness of the proposed structure and method.

Dual three-phase permanent magnet synchronous motors (DTP-PMSMs) are susceptible to both nonperiodic and periodic harmonic disturbances due to factors such as nonsinusoidal back electromotive force (EMF), inverter nonlinearity, and winding asymmetry, which degrade system performance. To address the insufficient suppression of periodic harmonics in traditional active disturbance rejection control (ADRC), this article proposes an adaptive linear neuron-augmented ADRC (ALNA-ADRC) strategy. By embedding an adaptive linear neuron (ALN) into the ADRC framework, the proposed method precisely suppresses periodic harmonics, such as the 5th and 7th harmonics, in the harmonic plane while maintaining ADRC's robustness against nonperiodic disturbances. Furthermore, by decoupling the observer bandwidth from the control law gain, the parameter tuning process of ADRC is simplified. Experimental results demonstrate that the proposed method significantly reduces the total harmonic distortion (THD) of the current, achieving a minimum THD of 6.55% under steady-state conditions. In addition, it exhibits superior harmonic suppression capability and stability under complex operating conditions, including parameter mismatch, variable speed, and sudden load changes.

The phenomenon of market power abuse in carbon trading, leading to deviations in carbon quota prices from normal competitive levels, poses a significant challenge to the economic dispatch of carbon capture power plants. In response, this paper introduces a comprehensive market power assessment methodology tailored to the carbon market environment in China, encompassing pre-market, mid-market, and post-market phases. Furthermore, it proposes market power restraint measures based on the incentive compatibility principle. Comparative analysis is conducted to validate that the implementation of market power restraint can prevent the masking of true cost information, thereby enhancing the low-carbon operational efficiency of carbon capture power plants.

Traditional rotary motors may encounter some problems when applied to large-diameter equipment due to the drawbacks of traditional transmission. The arc permanent magnet torque motor (APMTM) using stator splicing technology can improve the accuracy, efficiency and reliability of the equipment when applied to direct drive systems. It can be significant for overcoming the shortcomings of traditional rotating motors and promoting production. APMTM has the problem of large torque ripple caused by end effect. A method is proposed to suppress end effect from the perspective of adjusting the stator center angle and the stator adjacent angles, which can be used to suppress the torque ripple of APMTM. The mathematical derivation method and finite element method are used to analyze and calculate the end force of the motor. The proposed method of APMTM end effect suppression suitable for any number of unit motors is obtained. It can significantly suppress torque ripple caused by end effect in APMTM. This method provides experience for the structure design of the APMTM for the suppression of torque ripple.

This paper calculates the losses of the wet-type asymmetric dual-three-phase PMSM used in aviation electric fuel pumps, and analyzes the heat generation of the motor. First, accurately calculate the losses of each part of the motor, including iron losses, eddy current losses, copper losses, viscous losses and other factors. The losses under the three working conditions are compared and analyzed, and the results show that the viscous loss is greatly affected by the speed. Then, the temperature rise of the motor under different working conditions is calculated based on the calculated losses. The results show that the temperature rise of the motor is within a reasonable range and meet industrial requirements.

Direct air capture (DAC) offers a potential solution for capturing carbon dioxide directly from the atmosphere, making it a promising technology in the field of negative carbon solutions. However, its current stage is characterized by high costs and a lack of maturity, placing it in the early phases of commercial application. To address these challenges, this paper introduces a novel cost-sharing mechanism specifically designed for DAC equipment within the context of carbon emission management in power systems. The aim is to facilitate both DAC capacity configuration and cost allocation. We begin by dissecting the operational principles of DAC and reviewing ongoing demonstration projects. We then pioneeringly devises a unified operational model (UOM) for DAC, which integrates electricity and carbon considerations seamlessly. Following this, we introduce an enhanced version of the carbon emission flow (CEF) theory, customized for DAC deployment. This sets the stage for the design of a DAC-specific carbon capture cost-sharing mechanism. Building on these foundations, we develop a meticulous DAC capacity planning model. This is accompanied by a cost allocation methodology based on the Shapley value framework. The ultimate goal is equitable cost allocation among stakeholders and optimized DAC capacity planning. Case studies validate the efficacy of both the proposed model and the cost allocation methodology. The insights from this study contribute to advancing theoretical frameworks for carbon capture technologies and have practical implications for engineering designs in real-world implementation.

In the development of more-electric aircraft, the motors with high torque density and specific power are required within the weight restriction. In this article, a novel hybrid axial transverse flux permanent magnet motor (HATF-PMM) is proposed with compound permanent magnet (PM) rotor, which exhibits great torque capacity to satisfy the requirement in more-electric aircraft. The method of electromagnetic characteristic superposition is highlighted in this article for the first time to decouple the magnetic field and reduce dimensionality. Considering the calculating time and accuracy, an analytical model based on the subdomain method is utilized to calculate the magnetic field of the proposed HATF-PMM and further obtain the electromagnetic characteristics, which is verified by finite-element analysis (FEA). Then, the HATF-PMM is optimized with the objective of high specific power by using the analytical model. In the end, the analysis results and performance of the proposed HATF-PMM are validated by the prototype experiment, which proves that the HATF-PMM has great potential in the application of more-electric aircraft.

This paper proposes a trajectory-optimization problem for spacecraft close proximity to a noncooperative target, aiming at the generation of a six-degree-of-freedom (DOF) trajectory with the fuel-optimal objective value and considering multiple constraints on the control magnitude, line-of-sight, and glide-slope. The line-of-sight and glide-slope constraints are coupled between translational and rotational motions. The dual quaternion is an effective method for establishing the translationally and rotationally coupled model, because it can represent the translation and rotation in an integrated manner. Therefore, in this study, the trajectory-optimization problem of spacecraft close proximity coupled with position and attitude is established using dual quaternions. Next, the close-proximity trajectory-optimization problem is converted into a nonlinear programming problem, which can be solved efficiently using well-developed algorithms such as convex optimization. However, the zero-order hold used in the discrete method of convex optimization is an equidistant dispersion, which cannot guarantee the satisfaction of constraints between discrete points. Therefore the pseudospectral convex method is proposed using nonequidistant collocation points to mitigate the problem of constraint violation between discrete points and improve the accuracy and computational efficiency of the algorithm. The proposed algorithm can be applied to tasks such as rendezvous and docking with noncooperative targets and close proximity. Finally, the effectiveness of the proposed method was validated via numerical simulation, and the results were compared with those of the existing approach, GPOPS. The results indicate that the proposed algorithm is superior to GPOPS in computational efficiency and objective values.

To suppress the vibration of dumbbell-shaped spacecraft by combining distributed cooperative control (DCC) and component synthesis vibration suppression (CSVS). The dumbbell-shaped spacecraft is divided into control sub-modules, and the dynamic model for distributed control is established according to Newton–Euler method and Lagrange’s equations of second kind; The distributed controller is designed by combining graph theory and consistency theory, and the stability of the closed-loop system is analyzed based on Lyapunov theory; CSVS + DCC method is proposed to suppress the vibration of dumbbell spacecraft. Finally, numerical simulation is used to verify the superiority and effectiveness. The large angle attitude maneuver of dumbbell spacecraft can be completed by CSVS + DCC method. Compared with bang-bang control, the stabilization time is shortened by 25.76

Permanent magnet synchronous motors (PMSMs) are widely used in the aerospace field due to the high power density, high torque density, and high efficiency. Due to the excellent flux-focusing performance, PMs in Halbach array can significantly increase the peak fundamental air-gap flux density of PMSMs and hence, a better torque capacity. In this article, 8-pole 9-slot motors with various PM configurations are compared in terms of optimization methods, magnetic flux density, open-circuit electromotive force, and on-load torque by finite element analysis (FEA). The results show that the machine in Halbach array with 45 ° magnetization has significant flux-focusing capability, which can effectively improve the torque density. Moreover, the machine in Halbach array with 45 ° magnetization exhibits the smallest PM eddy current loss and hence, a higher efficiency.

The potential applications of two-dimensional (2D) molybdenum disulfide (MoS2) in ultrathin digital logic circuits have stimulated intensive research. When 2D MoS2 connects to external circuits to form field-effect transistors based on complementary metal-oxide-semiconductor technology, transport of both electrons (n type) and holes (p type) is necessary. However, the p-type ohmic contact to MoS2 remains challenging. In the current work, based on first-principles calculations, we propose metal surface oxidation, serving as a general route for the regulation of the Schottky barrier from n to p type and the suppression of Fermi-level pinning simultaneously at metal-MoS2 interfaces. By introducing an ultrathin insulating layer, the oxidized metal surface layer has the following four advantages: (1) Surface oxidation greatly increases the work function of the metal surface, which is crucial for the realization of a p-type contact. (2) Surface oxidation passivates the metal surface and hence suppresses the metal-induced gap states in MoS2. (3) Due to the out of plane pz-orbital coupling between oxygen and sulfur, significant quasibonding-induced gap states appear above the valence-band maximum of MoS2, which is beneficial to the reduction of p-type Schottky barrier height. (4) Surface oxidation is easily achieved for common transitional precious metal substrates, which ensures that it is a viable way to achieve p-type ohmic contacts in metal-MoS2 heterojunctions. Hence, this study suggests that metal surface oxidation is a general route to p-type ohmic contacts for MoS2 and other 2D semiconductors with out of plane orbitals in the valence band.

Space debris is growing dramatically, which poses a serious threat to space exploration activities. Especially the large non-cooperative target, such as malfunctioning satellites. This paper proposes a capture mechanism for the launch adapter ring that is usually available on satellites as the capture object, which used for in-orbit capture of malfunctioning satellites. Firstly, introduce the design conditions, the overall design plan, carry out the mechanical mechanism design, sensor system configuration, electrical system design, and explain the capture process. Secondly, analyze the capture tolerance. Thirdly, by establishing the kinematics model of the captured finger, use D-H parameter method for kinematic analysis, and analyze the dynamic in the capturing process. In addition, the control strategy is proposed, and the clamping force model, friction identification model, and servo control strategy are established. Then, the prototype is manufactured, and the clamping force, stiffness, capture loads, and capture tolerance are tested. Finally, the air-floating platform is used to verify the capture test of the launch adapter ring in a microgravity environment. The experimental results show that the developed capture mechanism meets the design conditions and has the ability to capture launch adapter ring of satellites in orbit.

Sm-modification has recently attracted widespread attention as an optimized method for enhancing the elec-tromechanical properties of Pb-based perovskite ferroelectrics. The present study extends the application of Sm-modification to the Pb(Ni1/3Nb2/3)O3-PbZrO3-PbTiO3 (PNN-PZT) ceramics, aiming to improve their electro-mechanical properties. The impact of Sm-doping on the phase structure, microstructure, domain morphology, dielectric and piezoelectric properties was comprehensively investigated. The results demonstrate that the Sm-doping enhances the dielectric and piezoelectric properties while retaining competitive ferroelectric-paraelectric phase transition temperature (Tm). Notably, for the 2 mol% Sm-doped samples, a significant piezoelectric coefficient d33 of 1130 pC/N and a high Tm of 130 degrees C were achieved, accompanied by an improved dielectric constant (epsilon r) and electromechanical coupling factor (kp). The comprehensive properties of Sm-doped PNN-PZT ceramics exceed the general trend observed in current Pb-based ferroelectric ceramics. This research confirms the effectiveness of the Sm-modification method in PNN-PZT systems, establishing it as a promising candidate for high-performance electromechanical applications.