蜂巢状有源配电网中多端口能量枢纽控制策略

作为一种适应高比例分布式新能源接入的新型配电网架构,蜂巢状有源配电网利用多端口能量枢纽(multi-port energy hub,MEH)可实现多微电网/配网单元间功率的互联互济,如MEH中包含储能设备,可以进一步提升新能源利用率和电网可靠性。文中提出一种含储能的MEH及其分层协调控制策略。上层控制根据储能系统的荷电状态和配电网运行状态协调控制储能变流器与各并网端口变流器之间的功率分配,使得MEH在平抑新能源波动、配网故障恢复等运行模式下均能够对内部储能系统进行能量管理。下层控制通过将储能变流器有功功率的微分值反馈至储能系统控制环路进行补偿,提高储能变流器输入/输出有功功率响应速度。文中设计了MEH控制系统关键参数,利用MATLAB/Simulink对MEH在配电系统中的应用进行仿真。不同工况下的仿真对比验证了所提分层协调控制策略的有效性,证明该策略能够延长储能系统工作时间,提高储能系统有功功率变化率,减小直流母线的电压波动。     

基于I-DPWM的三电平中点钳位光伏逆变器漏电流抑制方法

对于三电平中点钳位光伏逆变器,基于断续脉宽调制(discontinuous pulse width modulation, DPWM)并通过选择特定矢量进行钳位控制的方法,存在矢量分解计算时间长、注入共模电压分量和漏电流过大等不足。对此,提出了一种基于I-DPWM的三电平中点钳位光伏逆变器漏电流抑制方法。通过计算各类DPWM等效调制波来解析注入的低频共模电压分量。针对低频共模电压分量最小的DPWM1,在低频共模电压不连续点注入新的零序分量,通过减小低频共模电压来抑制漏电流幅值。同时,采用载波实现DPWM,免去了复杂的矢量运算。最后,在Matlab/Simulink平台建立了20 kW三电平中点钳位光伏逆变器的仿真模型,同时结合所设计的125 W实验样机验证了所提方法的有效性。     

Minimizing Energy Barrier in Intermediate Connection Layer for Monolithic Tandem WPeLEDs with Wide Color Gamut

Perovskite light-emitting diodes (PeLEDs) show promising prospects in the wide color gamut display owing to their ultra-narrow full width at half maximum (FWHM). However, up to now, all perovskite white LEDs integrated by standard red, green, and blue perovskite emitters, namely, monolithic white PeLEDs (WPeLEDs), have been rarely reported, owing to facing some issues, e.g., solvent incompatibility in solution technique, ion exchange, and energy transfer between different emission centers. Herein, centered on these issues, an optimal intermediate connection layer (ICL) of Po-T2T/LiF/Ag/HAT-CN/MoO₃ is adopted to successfully develop monolithic tandem multicolor PeLEDs and WPeLEDs for the first time. The multicolor PeLEDs can achieve the best external quantum efficiency of 1.8% and the highest luminance of 4844 cd m⁻². Besides, the red/green/blue (R/G/B) monolithic tandem WPeLED shows a standard white International Commission on Illumination coordinate of (0.33, 0.33) and achieves an extremely wide color gamut reaching  National Television Standards Committee of 130%. This study is the first to realize the standard R/G/B co-electroluminescence in a monolithic perovskite device and offers a feasible strategy for developing wide-color gamut perovskite displays.     

Electrical and Thermal Transport Properties of Ge1–xPbxCuySbyTeSe2y

Balancing the contradictory relationship between thermoelectric parameters, such as effective mass and carrier mobility, is a challenge to optimize thermoelectric performance. Herein, the exceptional thermoelectric performance is realized in GeTe through collaboratively optimizing the carrier and phonon transport via stepwise alloying Pb and CuSbSe₂. The formation energy of Ge vacancy is efficiently bolstered by alloying Pb, which reduces carrier density and carrier scattering to maintain superior carrier mobility in GeTe. Additionally, CuSbSe₂, acting as an n-type dopant, further modulates carrier density and validly equilibrates carrier mobility and effective mass. Accordingly, the promising power factor of 45 µW cm⁻¹ K⁻² is achieved at 723 K. Meanwhile, point defects are found to significantly suppress phonons transport to descend lattice thermal conductivity by Pb and CuSbSe₂ alloying, which barely impacts the carrier mobility. A combination with superior carrier mobility and lower lattice thermal conductivity, a maximum ZT of 2.2 is attained in Ge_0.925Pb_0.075Cu_0.005Sb_0.005TeSe_0.01, which corresponds to a 100% promotion compared with that of intrinsic GeTe. This study provides a new indicator for optimizing carrier and phonon transport properties by balancing interrelated thermoelectric parameters.     

Spidermen Strategy for Stable 24% Efficiency Perovskite Solar Cells

The interface energetics-modification plays an important role in improving the power conversion efficiency (PCE) among the perovskite solar cells (PSCs). Considering the low carrier mobility caused by defects in PSCs, a double-layer modification engineering strategy is adopted to introduce the “spiderman” NOBF₄ (nitrosonium tetrafluoroborate) between tin dioxide (SnO₂ and perovskite layers. NO⁺, as the interfacial bonding layer, can passivate the oxygen vacancy in SnO₂, while BF₄⁻ can optimize the defects in the bulk of perovskite. This conclusion is confirmed by theoretical calculation and transmission electron microscopy (TEM). The synergistic effect of NO⁺ and BF₄⁻ distinctly heightens the carrier extraction efficiency, and the PCE of PSCs is 24.04% with a fill factor (FF) of 82.98% and long-term stability. This study underlines the effectiveness of multifunctional additives in improving interface contact and enhancing PCE of PSCs.     

双循环策略下岸桥与跨运车的联合调度

集装箱码头采用跨运车能够减少作业环节和码头机械设备的种类与数量,同时缓存区容量的设置至关重要。首先,为降低码头总完工时间、提高码头作业效率,并解决采用跨运车作为水平运输设备与岸桥进行联合装卸作业时产生的时空协调问题,引入了双循环操作策略,对岸桥与跨运车的联合作业序列优化问题进行研究。其次,建立以总完工时间最小化为目标,考虑岸桥与跨运车双循环操作的实际约束、岸桥缓存区容量限制、安全时间等约束的混合整数规划模型。然后,针对传统禁忌搜索（TS）算法的局限性,加入贪婪算法、多种邻域搜索方式、响应性策略,设计了基于贪婪算法的响应性TS算法,并进行了数值实验。实验结果验证了所提模型与算法的有效性。最后,通过对缓存区容量与跨运车数量、岸桥与跨运车配比的实验分析,得出了最优的跨运车数量和缓存区容量、岸桥与跨运车配比。结果表明：与传统码头设备配置相比,双循环策略可减少跨运车使用数量,提高岸桥与跨运车使用率。     

材料饱和特性对永磁电机性能的影响研究

针对非晶材料饱和磁密低,非晶永磁电机性能易受铁心饱和作用影响的问题,本文提出了饱和磁密解析模型用以分析定子铁心齿部饱和作用产生的影响,该模型的特点是利用饱和前后气隙磁密的比率代替实验实测的电压比率求解出饱和系数,从而实现在电机初始设计阶段饱和效应对电机性能影响的分析与研究。基于该饱和磁路解析模型分析了定子铁心饱和对非晶永磁电机绕组电感、谐波电流以及逆变器供电情况下由载波引起的损耗的影响规律。     

一种基于Arnold置乱和DCT编码的无载体信息隐藏方法北大核心CSCD

近年来十分火热的搜索映射式无载体信息隐藏虽具有一定的鲁棒性,但其隐藏容量较低、传输负载大且算法复杂度高。针对以上问题,该文章提出一种基于Arnold置乱和离散余弦变换(discrete cosine transform,DCT)编码的无载体信息隐藏方法。该算法先对图片进行Arnold置乱,再对DCT后的低频系数进行编码,接着更换置乱参数来构建索引表。选择索引表中与秘密信息相同的编码值所对应的参数构建候选队列,最后筛选出鲁棒性强的参数作为密钥发送给接收方。实验结果表明,该方法与现有方法相比大大提高了嵌入容量,拥有更强的抗JPEG压缩性能。并且减少了传输负载,算法简捷,具有较强的应用价值。     

Fabrication of Fe3O4 Dots Embedded in 3D Honeycomb‐Like Carbon Based on Metallo–Organic Molecule with Superior Lithium Storage Performance

A novel metallo–organic molecule, ferrocene, is selected as building block to construct Fe₃O₄ dots embedded in 3D honeycomb‐like carbon (Fe₃O₄ dots/3DHC) by using SiO₂ nanospheres as template. Unlike previously used inorganic Fe₃O₄ sources, ferrocene simultaneously contains organic cyclopentadienyl groups and inorganic Fe atoms, which can be converted to carbon and Fe₃O₄, respectively. Atomic‐scale Fe distribution in started building block leads to the formation of ultrasmall Fe₃O₄ dots (≈3 nm). In addition, by well controlling the feed amount of ferrocene, Fe₃O₄ dots/3DHC with well‐defined honeycomb‐like meso/macropore structure and ultrathin carbon wall can be obtained. Owing to unique structural features, Fe₃O₄ dots/3DHC presents impressive lithium storage performance. The initial discharge and reversible capacities can reach 2047 and 1280 mAh g^?1 at 0.05 A g^?1. With increasing the current density to 1 and 3 A g^?1, remarkable capacities of 963 and 731 mAh g^?1 remain. Moreover, Fe₃O₄ dots/3DHC also has superior cycling stability, after a long‐term charge/discharge for 200 times, a high capacity of 1082 mAh g^?1 can be maintained (80% against the capacity of the 2nd cycle).