基于DDPG的柔性伺服系统级联陷波器设计

针对柔性伺服系统的多频谐振抑制问题,提出一种基于DDPG的级联陷波器参数整定方法。以系统速度环开环bode图及陷波器bode图预处理结果作为训练数据,并以相位裕度作为奖励函数训练神经网络,实现所设计的伺服系统级联陷波器深度及宽度参数优化训练。搭建了三质量柔性伺服系统实验平台,并开展了多频谐振抑制实验,实验结果表明所提出的参数选择方法能够 找到具有最大相位裕度的陷波器参数,并有效地抑制系统多频谐振。     

计及可靠性收益的配电网柔性多状态开关及分布式电源综合优化配置

柔性多状态开关(flexible multi-state switch,FMS)是支撑新型电力系统背景下配电网运行控制能力提升和可再生能源接入渗透率改善的重要技术装备,针对现有配电网中FMS的规划并未详细考虑FMS与分布式电源(distributed generation,DG)的协调配置,以及对于FMS接入带来的可靠性提升考虑不足的问题。文章在规划配置阶段详细考虑了含FMS和DG的协同优化运行,并充分计及FMS接入带来的可靠性收益,构建了基于嵌套优化的FMS和DG选址定容双层优化配置模型。针对双层嵌套规划模型求解的复杂性,提出了基于改进粒子群算法和GAMS(general algebraic modeling language)算法相结合的模型求解策略,以改造后的IEEE 33节点算例系统为例,对所提出模型和方法的有效性进行了验证,结果表明提出的方法相比传统单一FMS规划具有更好的经济性,能最大程度地降低配电网年综合费用,同时减少用户因停电带来的损失。     

考虑综合能源站柔性调控作用的城市配电网多阶段规划方法

随着城市经济发展与终端用能电气化的普及,以制冷用电为首的电负荷需求持续增加且峰谷差情况愈发严重化,导致现有配电网运行负担逐渐加重。在此背景下,将综合能源站(IES)作为多能流耦合节点,在配电网中引入多能协调互补及蓄能移峰功能,计及多个阶段负荷发展及多类型负荷特征,提出在IES柔性调控作用下的配电网多阶段规划方法。基于IES能流结构及其运行机制,分别在不同气候类型地区负荷模拟场景下,以总规划期内投资与运行经济性最优为目标,建立由线路、变电站和IES构成决策对象的配电网双层多阶段规划模型,规划与运行层模型通过决策变量关联达成一体化协同求解。通过修改后的IEEE 33节点配电系统对所提方法的有效性进行校验,并进一步将所提方法应用于某地实际152节点配电系统,分析不同负荷特征下配电网规划运行效益、负荷峰谷差调节效果及IES运行状况,得出计及IES的城市配电网规划方法的实用性结论。     

柔性直流输电系统接入交流电网的高频谐振风险运行方式辨识

柔性直流输电系统接入交流电网后存在高频谐振的风险,研究表明交流电网运行方式变化与高频谐振的产生存在内在关联。针对交直流系统中的高频谐振问题,首先构建了柔性直流输电系统直流侧和交流侧计及串补站的等效阻抗模型,分析了柔性直流输电系统接入交流电网的高频谐振机理。对柔性直流输电系统交流侧运行方式变化(特别是线路发生N-1、N-2故障)下等效阻抗的变化规律进行了理论分析和总结。此外,提出了一种柔性直流输电系统接入交流电网的高频谐振风险运行方式辨识方法,并以某地区电网局部交直流系统实际数据为例进行仿真,验证了所提辨识方法的有效性。     

考虑储能备用的电动汽车负荷连续追踪弃风曲线优化模型

在大力推动高比例可再生能源并网的背景下,风电的强随机波动特征导致的大量弃风问题给电力系统的经济可靠运行带来了挑战,而电动汽车、储能等作为需求侧的灵活性资源参与曲线追踪交易为弃风问题带来了解决方案。首先,分析了电动汽车消纳风电的可行性;然后,对电动汽车聚合负荷消纳风电的交易模式进行了梳理,聚焦连续曲线追踪交易,在充分考虑电动汽车聚合的物理经济约束下建立了混合整数线性规划模型以求解聚合调用方案。由于电动汽车的移动储能能力与追踪效果有限,引入储能系统进行联合优化,采用逐步搜索法在降低聚合成本的同时,得到储能的最优容量与功率配置以及同时优化物理弃风电量与经济成本的聚合方案。算例分析结果表明：考虑储能备用的聚合方法能够提高风电曲线的追踪精度,减小聚合成本,验证了所建模型在连续曲线追踪中的可行性与适用性,可为曲线追踪交易市场的完善与新型电力系统的建设提供借鉴。     

基于B2B-MMC的柔性互联变电站优化调度方法

针对传统变电站内主变之间采用单母线分段开关难以准确调控潮流问题,提出一种基于背靠背模块化多电平换流器（B2B-MMC）的柔性互联变电站优化调度方法。首先,提出含柔性互联变电站的配电网架构,实现潮流的连续性控制及多区域间互相协调;然后,设计柔性互联变电站架构下的一种潮流优化调度方法,采用遗传算法对换流器进行赋值,利用改进交替迭代法进行潮流计算,实现配电网潮流的主动调控;最后,通过仿真模型验证了本文所提控制方法的有效性和合理性。     

发用两侧参与调峰的现货市场联合出清模式设计

针对新型电力系统下新能源装机容量大,发电侧调峰资源紧缺,弃风、弃光现象严重的问题,文中设计了一种考虑发用两侧参与调峰的现货市场联合出清模式,将发电侧深度调峰、柔性负荷调峰、新能源消纳与现货市场相结合,充分发掘发用两侧的调峰能力。首先,将独立储能和用户作为用户侧调峰资源,并根据用户是否具有实时跟踪调度指令的能力,将其分为灵活调节用户和非灵活调节用户,在此基础上设计了发用两侧参与调峰的日前市场和实时市场出清模式并建立出清模型。其次,综合考虑各市场主体的贡献和受益程度,设计了调峰辅助服务费用的结算与分摊机制。最后,通过算例验证了所提市场模式对于新能源消纳的有效性和合理性。算例分析中,文中所提市场模式相比仅发电侧参与调峰的模式可降低17.3%的弃风弃光量。     

Metal Micropatterning by Triboelectric Spark Discharge

Metal micropatterns play critical roles in flexible electronics. However, the lack of versatile strategies for micropatterning of diverse metal materials on various thin, flexible or stretchable substrates has limited the rapid development of flexible electronics. Here, a metal micropatterning method by triboelectric spark discharge under atmospheric environment is developed, where a triboelectric nanogenerator (TENG) is employed to precisely and safely control the voltage, current, and frequency of the spark discharges. Micropatterns of metal films like gold, silver, copper, aluminum and platinum are successfully fabricated on substrates of polyimide, polyethylene terephthalate, polyvinyl chloride, polydimethylsiloxane, paper or latex, even on ultrathin substrates (5 μm thick) without damage, where the feature sizes of metal patterns are controllable from 20 μm to 1 mm. Experimental insights into the triboelectric spark discharge behaviors and the pattern feature sizes control are discussed. A straightforward fabrication of metal patterns on the balloon surface or human skin through “handwriting” by a pencil as discharge electrode is realized. Besides metals, extended processibility of conductive materials like carbon nanotubes, graphene, MXene, graphite, carbon fibers, and conductive polymers are also demonstrated. This work proves the possibility of microfabrication by TENG, which is of simplicity and attractiveness for flexible electronics.     

Flexible Nonvolatile Transistor Memory with Solution‐Processed Transition Metal Dichalcogenides

Nonvolatile field‐effect transistor (FET) memories containing transition metal dichalcogenide (TMD) nanosheets have been recently developed with great interest by utilizing some of the intriguing photoelectronic properties of TMDs. The TMD nanosheets are, however, employed as semiconducting channels in most of the memories, and only a few works address their function as floating gates. Here, a floating‐gate organic‐FET memory with an all‐in‐one floating‐gate/tunneling layer of the solution‐processed TMD nanosheets is demonstrated. Molybdenum disulfide (MoS₂) is efficiently liquid‐exfoliated by amine‐terminated polystyrene with a controlled amount of MoS₂ nanosheets in an all‐in‐one floating‐gate/tunneling layer, allowing for systematic investigation of concentration‐dependent charge‐trapping and detrapping properties of MoS₂ nanosheets. At an optimized condition, the nonvolatile memory exhibits memory performances with an ON/OFF ratio greater than 10⁴, a program/erase endurance cycle over 400 times, and data retention longer than 7 × 10³ s. All‐in‐one floating‐gate/tunneling layers containing molybdenum diselenide and tungsten disulfide are also developed. Furthermore, a mechanically‐flexible TMD memory on a plastic substrate shows a performance comparable with that on a hard substrate, and the memory properties are rarely altered after outer‐bending events over 500 times at the bending radius of 4.0 mm.     

Near‐Infrared Photodetectors Based on MoTe2/Graphene Heterostructure with High Responsivity and Flexibility

2D transition metal dichalcogenides (TMDCs) have attracted considerable attention due to their impressively high performance in optoelectronic devices. However, efficient infrared (IR) photodetection has been significantly hampered because the absorption wavelength range of most TMDCs lies in the visible spectrum. In this regard, semiconducting 2D MoTe₂ can be an alternative choice owing to its smaller band gap ≈1 eV from bulk to monolayer and high carrier mobility. Here, a MoTe₂/graphene heterostructure photodetector is demonstrated for efficient near‐infrared (NIR) light detection. The devices achieve a high responsivity of ≈970.82 A W^?1 (at 1064 nm) and broadband photodetection (visible‐1064 nm). Because of the effective photogating effect induced by electrons trapped in the localized states of MoTe₂, the devices demonstrate an extremely high photoconductive gain of 4.69 × 10⁸ and detectivity of 1.55 × 10¹¹ cm Hz^1/2 W^?1. Moreover, flexible devices based on the MoTe₂/graphene heterostructure on flexible substrate also retains a good photodetection ability after thousands of times bending test (1.2% tensile strain), with a high responsivity of ≈60 A W^?1 at 1064 nm at V _DS = 1 V, which provides a promising platform for highly efficient, flexible, and low cost broadband NIR photodetectors.