孤岛微网多场景机会约束动态调度

风光出力与负荷在时空分布上具有波动性和间歇性,该文按风速段拟合风电预测误差分布,采用Beta分布拟合光伏出力分布,按时段拟合负荷分布.根据风速和调度时段的不同采用卷积推广方法求解各场景下约束条件成立的分布函数.以微电网运行维护成本和环境成本最小为目标,构建微电网多目标机会约束动态调度模型.采用改进多目标教与学算法对模型进行求解.算例验证了模型与算法的有效性.然后采用蒙特卡罗模拟法产生随机场景进行调度.其结果表明,与传统机会约束调度(单场景)相比,多场景机会约束动态调度的后验置信水平更高,进一步确保了系统的安全性,提高了策略的鲁棒性.     

基于电力电子变压器的三端协调控制

为研究电力电子变压器对主网、交流微网、直流微网的三端协调控制,根据微网内分布式能源出力与功率缺额,提出了一种确定储能荷电状态预期值的方法。并基于此荷电状态值,综合考虑微网内源、荷、储三者关系,将微网运行状态划分为电源型微网和负载型微网。电力电子变压器根据微网类型,控制交直流微网功率流向与大小,最大化消纳分布式能源,以减少微网对配网的功率回馈次数及回馈时产生的功率损耗。仿真结果和实验数据验证了所提划分方法和控制策略的有效性。     

Two‐loop power‐flow control of grid‐connected microgrid based on equivalent‐input‐disturbance approach

This study employed the equivalent‐input‐disturbance (EID) approach to devise a two‐loop power‐flow control system that controls the output current of an inverter so as to regulate the flow of active and reactive power between a distributed generation unit and a utility grid. It actively eliminates disturbances that degrade the power quality of a microgrid. The pq theory and an all‐pass filter are employed to generate an instantaneous reference current for the control system based on the prescribed active and reactive power of a utility grid terminal. The inner loop consists of a disturbance compensator and a state observer. The disturbance compensator uses information acquired from the state observer to estimate disturbances, such as drops and harmonics in the grid voltage, and compensates for them by incorporating the equivalent input disturbance into the control law. The outer loop consists of a resonance‐based internal model and a state‐feedback controller, which enables the output current of inverter to track the instantaneous reference current. The small‐gain theorem ensures the stability of the system. The system improves the power quality and guarantees that the flow of active and reactive power from the grid and inverter has low harmonic distortion. Simulations demonstrated the effectiveness of the system. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

现代社区中的传统岭南人居空间——广州亚运媒体村项目设计

本文通过传统岭南水乡聚落意象的文化提炼,结合广州亚运媒体村项目工程设计实践,以岭南传统居住聚落进行多角度的分析和文脉延续传承的研究,探索现代社区中的传统岭南人居空间设计新思路。     

直流微网孤岛运行状态电压稳定性分析

直流电压是直流电网运行中重要的状态变量。文章针对由多种微电源及就地负载组成的直流微电网系统,以之作为研究对象,利用阻抗比例判据判别直流微电网电压的稳定性。该方法通过将电源子系统的总输出阻抗对负载子系统的总输入阻抗的比值看作一个等效回路增益,再用 Nyquist稳定性判据分析系统的稳定性。仿真结果表明了直流微电网母线电压稳定性与各参数之间的关系。     

基于储能SOC状态的微电网能量优化调度策略研究

为了满足微电网能量调度要求,根据储能系统在不同运行模式下的功能定位,提出了一种基于储能SOC状态的微电网能量优化调度策略。在调度响应方面,利用该策略可实现微电网与配电网功率交换遵循调度计划,保证调度计划的有效性。在经济运行方面,利用该策略可实现公共连接点配电变压器的最佳运行,降低电力系统损耗。该策略充分考虑了电力公司通过改变用电电价鼓励用户参与需求侧管理的需求,结合实时电价调整储能SOC状态实现用电成本最低。利用该策略可实现微电网离网时稳定运行,提高可再生能源利用率,保证重要负荷的供电,防止蓄电池的过充及过放等。     

Ionothermal synthesis of a new cobalt metal-organic framework based on tetranuclear cobalt clusters

A new metal-organic network (EMIM)[Co₂(hip)₂(μ₃-OH)]·H₂O (1), (H₂hip = 5-hydroxyisophthalic acid and EMIM = 1-ethly-3-methylimidazolium), has been synthesized by the ionothermal reaction of cobalt nitrate, H₂hip and [EMIM]Br ionic liquid. Single-crystal X-ray diffraction analysis reveals that 1 exhibits a two-dimensional (2D) bilayer constructed from tetranuclear [Co₄(μ₃-OH)₂] building units and hip²⁻ linkers. There are square cavities with the dimension of 10.161 × 10.868 Å. The [EMIM]⁺ cations are located in the cavities, which have the hydrogen bonding interactions with the bilayer. Further more, the strong hydrogen bonds between the carboxylate and hydroxyl oxygen atoms of hip²⁻ ligands and lattice water molecules extend the 2D layer into a 3D supramolecular network. The magnetic properties of 1 have been investigated by variable-temperature magnetic susceptibility and magnetization measurements, and the results reveal that there exist antiferromagnetic interactions.