Robust Input-Output Energy Decoupling for Uncertain Singular Systems

This paper addresses the robust input-output energy decoupling problem for uncertain singular systems in which all parameter matrices except E exist as time-varying uncertainties. By means of linear matrix inequalities (LMIs), sufficient conditions are derived for the existence of linear state feedback and input transformation control laws, such that the resulting closed-loop uncertain singular system is generalized quadratically stable and the energy of every input controls mainly the energy of a corresponding output, and influences the energy of other outputs as weakly as possible. Keywords Uncertain singular systems - generalized quadratical stability - input-output energy decoupling - linear matrix inequality (LMI) Xin-Zhuang Dong graduated from the Institute of Information Engineering of People’s Liberation Army, China, in 1994. She received the M. S. degree from the Institute of Electronic Technology of People’s Liberation Army, in 1998 and the Ph.D. degree from Northeastern University, China, in 2004. She is currently a post-doctoral fellow at the Key Laboratory of Systems and Control, CAS.Her research interests include singular and nonlinear systems, especially the control of singular systems such as H ∞ control, passive control and dissipative control. Qing-Ling Zhang received the Ph.D. degree from Northeastern University, China, in 1995. He is currently a professor with the Institute of Systems Science, Northeastern University. His research interests include singular systems, fuzzy systems, decentralized control, and H 2/H ∞ control.

Decoupling economic growth from CO_2 emissions: A decomposition analysis of China's household energy consumption

This paper analyzes Chinese household CO_2 emissions in 1994-2012 based on the Logarithmic Mean Divisia Index(LMDI) structure decomposition model, and discusses the relationship between household CO_2 emissions and economic growth based on a decoupling indicator.The results show that in 1994-2012, household CO_2 emissions grew in general and displayed an accelerated growth trend during the early 21 st century. Economic growth leading to an increase in energy consumption is the main driving factor of CO_2 emission growth(an increase of 1.078 Gt CO_2) with cumulative contribution rate of 55.92%, while the decline in energy intensity is the main cause of CO_2 emission growth inhibition(0.723 Gt CO_2 emission reduction) with cumulative contribution rate of 38.27%. Meanwhile, household CO_2 emissions are in a weak state of decoupling in general. The change in CO_2 emissions caused by population and economic growth shows a weak decoupling and expansive decoupling state, respectively. The CO_2 emission change caused by energy intensity is in a state of strong decoupling, and the change caused by energy consumption structure ?uctuates between a weak and a strong decoupling state.

Low-carbon economic development in Central Asia based on LMDI decomposition and comparative decoupling analyses

Low-carbon economic development is a strategy that is emerging in response to global climate change. Being the third-largest energy base in the world, Central Asia should adopt rational and efficient energy utilization to achieve the sustainable economic development. In this study, the logarithmic mean Divisia index(LMDI) decomposition method was used to explore the influence factors of CO2 emissions in Central Asia(including Kazakhstan, Uzbekistan, Kyrgyzstan, Tajikistan and Turkmenistan) during the period 1992–2014. Moreover, decoupling elasticity and decoupling index based on the LMDI decomposition results were employed to explore the relationship between economic growth and CO2 emissions during the study period. Our results show that the total CO2 emissions decreased during the period 1992–1998, influenced by the collapse of the Soviet Union in 1991 and the subsequent financial crisis. After 1998, the total CO2 emissions started to increase slowly along with the economic growth after the market economic reform. Energy-related CO2 emissions increased in Central Asia, mainly driven by economic activity effect and population effect, while energy intensity effect and energy carbon structure effect were the primary factors inhibiting CO2 emissions. The contribution percentages of these four factors(economic activity effect, population effect, energy intensity effect and energy carbon structure effect) to the total CO2 emissions were 11.80%, 39.08%, –44.82% and –4.32%, respectively, during the study period. Kazakhstan, Uzbekistan and Turkmenistan released great quantities of CO2 with the annual average emissions of 189.69×106, 45.55×106 and 115.38×106 t, respectively. In fact, their economic developments depended on high-carbon energies. The decoupling indices clarified the relationship between CO2 emissions and economic growth, highlighting the occurrence of a ’’weak decoupling’’ between these two variables in Central Asia. In conclusion, our results indicate that CO2 emissions are still not completely decoupled from economic growth in Central Asia. Based on these results, we suggest four key policy suggestions in this paper to help Central Asia to reduce CO2 emissions and build a resource-conserving and environment-friendly society.

The Influences of Energy Price Variation on the Prices of Other Industries: A Study Based on Input-Output Price Model

Energy has laid material foundation for human society during its development. Meanwhile, any change of price in the energy industry may influence social production and people’s life at all levels via an input-output mechanism under which the change related to energy is surely transmitted to other industries. The price change thus incurred in all industries may adversely affect the realization of macroeconomic objective-maintaining prices at a stable level. It is, therefore, needed to conduct an empirical research related to the impact of price change in energy industry on that in other industries. According to the data coming from “China’s 2015 Input-Output Extension Table (42 Departments)” and four hypothetical basis, this article focuses on four energy sectors and analyzes how deeply the price change of them, by use of input-output model, affects that of other industrial products under five conditions where each of their price rises by 10% individually or simultaneously, and why such an influence occurs. The results show that the price rising of the energies in question leads to an upward growth in the prices of other industrial products, especially when their prices go up simultaneously. Besides, the price increase in the four energy sectors doesn’t influence other industries in an accumulation form but actually leads to a rollback in some of other industries. It is recommended to adopt diversified pricing strategies for different energy products, thus maximizing the value of each specific energy, and meanwhile achieving the goals of energy consumption reduction and price equilibrium.

Coordinated restoration optimization of power-gas integrated energy system with mobile emergency sources

In an integrated energy system(IES) composed of multiple subsystems, energy coupling causes an energy supply blockage or shutdown in one subsystem, thereby affecting the energy flow distribution optimization of other subsystems.The energy supply should be globally optimized during the IES energy supply restoration process to produce the highest restoration net income. Mobile emergency sources can be quickly and flexibly connected to supply energy after an energy outage to ensure a reliable supply to the system, which adds complexity to the decision. This study focuses on a powergas IES with mobile emergency sources and analyzes the coupling relationship between the gas distribution system and the power distribution system in terms of sources, networks, and loads, and the influence of mobile emergency source transportation. The influence of the transient process caused by the restoration operation of the gas distribution system on the power distribution system is also discussed. An optimization model for power-gas IES restoration was established with the objective of maximizing the net income. The coordinated restoration optimization decision-making process was also built to realize the decoupling iteration of the power-gas IES, including system status recognition, mobile emergency source dispatching optimization, gas-to-power gas flow optimization, and parallel intra-partition restoration scheme optimization for both the power and gas distribution systems. A simulation test power-gas IES consisting of an 81-node medium-voltage power distribution network, an 89-node medium-pressure gas distribution network, and four mobile emergency sources was constructed. The simulation analysis verified the efficiency of the proposed coordinated restoration optimization method.

Decoupling Zeros of Positive Discrete-Time Linear Sys-tems

The notions of decoupling zeros of positive discrete-time linear systems are introduced. The relationships between the decoupling zeros of standard and positive discrete-time linear systems are analyzed. It is shown that: 1) if the positive system has decoupling zeros then the corresponding standard system has also decoupling zeros, 2) the positive system may not have decoupling zeros when the corresponding standard system has decoupling zeros, 3) the positive and standard systems have the same decoupling zeros if the rank of reachability (observability) matrix is equal to the number of linearly independent monomial columns (rows) and some additional assumptions are satisfied.

Decoupling of greenhouse gas emissions from economic growth in Cameroon

Knowledge of decoupling indicators and its determinants is useful for formulating targeted policy recommendations. To this end, the Log-Mean Divisia Index and Tapio models were applied in this paper to study the decoupling relationship among economic growth and GHG emissions in Cameroon over the period 1971-2014. The analyzes were conducted according to the three major periods that marked Cameroon after independence and the decoupling indicators were broken down into seven factors while considering the three main GHGs emitted in this country (i.e. CO2, CH4, and N2O). The results showed that weak decoupling, strong decoupling, and strong negative decoupling occurred in Cameroon during the periods 1971-1984 and 1994-2014 which represent the periods before and after the economic crisis, respectively. In addition to these three decoupling statuses, recessive decoupling only appeared during the economic crisis period (1984-1994). From 1971 to 1984 and between 1994 and 2014, carbon intensity, economic activity, population, and emission factor not only contributed to the increase of Cameroon’s GHG (particularly CO2) emissions but also prevented decoupling. Unlike the period 1984-1994, energy intensity contributed to reducing environmental pollution while promoting decoupling during the periods 1971-1984 and 1994-2014. Although all played an important role in decoupling, we found that after the introduction of natural gas into the country’s energy mix from 2007, the effect of renewable energies on the mitigation of Cameroon’s CO2 emissions remained higher than the substitution of fossil fuels. However, to develop a cleaner economy, Cameroon should maintain modest economic growth and continuously transform economic development pathways, while encouraging the use of renewable energy to further reduce energy intensity per unit of GDP per capita.

基于S变换模能量分析的直流电缆故障测距

针对现有高压直流电缆故障定位方法故障定位精度低、定位模型泛化能力差等问题,文中在考虑电缆故障后故障点产生的暂态信号中含有丰富的故障信息的特征,提出一种时频域能量分析的故障测距方法。该方法利用多分类支持向量机(SVM)的特性构建直流电缆故障定位模型,利用直流电缆相模解耦矩阵对电缆电气量解耦,并采用S变换进行时频域变换,将得到的模量构造模能量,将其作为样本对SVM模型训练。实验结果表明,所提方法对于不同故障类型在不同过渡电阻及不同位置故障下均可进行准确测距。

风-火-储耦合系统储能容量配置优化对比

为提升风电富集区域风电消纳水平及燃煤机组的灵活性,提出了基于热电共蓄式压缩空气储能的风-火-储耦合系统及系统调度策略,建立了系统的容量配置优化框架,并对7种布局方案进行了多目标优化。优化结果表明:电锅炉将弃风电量转化为热量时,燃煤机组的运行点向电力负荷下限更低的区域移动,风电上网空间增大,燃煤机组出力水平降低;加入热电共蓄式压缩空气储能子系统,使得燃煤机组电功率水平降低;换热器废热的回收进一步降低了燃煤机组产热水平;通过调整燃煤机组热出力,抽汽蓄热子系统能够实现抽汽热的时空平移,促使燃煤机组运行点向电力负荷下限更低的区域移动,可间接促进风电的消纳。综合来看,3种子系统相组合的最佳耦合方案可实现燃煤机组的热电解耦,从而提升了其深度调峰能力,在更大程度消纳风电能力的同时提升了系统的效率和环保性。

呼包鄂榆城市群居民生活用能碳排放差异及影响因素分析

在“双碳”目标背景下,居民生活碳排放研究日益被重视,以呼包鄂榆城市群为研究对象,利用碳排放系数法对城市群内居民生活用能碳排放进行核算,发现居民生活用能碳排放呈现逐年增长的态势,其中汽油、液化石油气、电力是构成居民生活用能碳排放的主要能源类型。然后运用LMDI模型分解居民生活用能碳排放影响因素,发现能源结构效应、人口效应和消费倾向效应对居民生活用能碳排放存在正向效应,能源价格效应则显示负向效应。运用脱钩模型对短期内经济发展及居民生活用能碳排放进行分析,结果显示,2017-2019年呼包鄂榆城市群的经济发展与居民生活用能碳排放之间存在较理想的脱钩状态;在未来的城市群建设过程中应提高节能技术、开发清洁能源、优化能源消耗结构、适度降低城镇化建设来降低居民生活碳排放。

绿色金融:破解“碳诅咒”困境的有效策略

本文立足资源型地区经济增长过度依赖化石能源的特征,探讨利用金融手段破解“碳诅咒”困境问题的路径。首先,将绿色金融嵌入包含二氧化碳排放的经济增长理论分析框架,通过数理模型,阐释绿色金融通过缓解资本价格扭曲、加速碳排放与经济增长脱钩的作用机理,证实绿色金融发展应当以资本配置达到最优为上限,避免由于绿色金融发展过度导致绿色产业领域产能过剩,从而制约其他产业的发展。其次,运用空间计量经济模型,对理论模型的现实解释力进行实证检验。主要研究结论包括,我国资源型省份过度依赖化石能源产业,更倾向于碳密集型发展,迈入“碳诅咒”困境;资源型地区的绿色金融发展可以通过缓解资本价格扭曲加速碳排放同经济增长的脱钩,进而破解资源型地区由“资源诅咒”引致的“碳诅咒”困境;资源型地区的绿色金融发展能够加强邻居地区的能源脱钩与碳脱钩。研究结论为有序推进绿色金融高质量发展提供有益指导,为破解资源型地区“碳诅咒”困境提供合理可行的政策思路。

基于碳承载力对河南省能源消费碳排放及其驱动因素的研究

基于河南省近20年的能源消费碳排放数据和陆地生态系统碳承载力数据,对近年来研究区碳排放量情况进行了分析,并采用LMDI因素分解模型和Tapio脱钩模型对碳排放驱动因素以及与经济耦合情况进行了探讨。结果表明:(1)2000—2020年,河南省碳排放量呈现“先急后缓”的增长状态,在2012年后增加量开始减少并逐渐趋于稳定。(2)整体上,经济产出效应和人口规模效应对碳排放起促进作用;与之相反,能源消费强度效应和能源消费结构效应抑制了碳排放,经济产出效应的影响在减少,能源消费强度效应的影响在增加。(3)由Tapio脱钩模型分析得出,河南省碳排放与经济增长之间以弱脱钩为主,脱钩指数逐年减小,逐步向强脱钩状态迈进。总体上,2000—2020年河南省碳排放情况得到了很好的控制,合理规划土地利用、提高新能源的消费比重、降低能源消费强度对该地区节能减排具有重要意义。

不耦合装药下岩石爆破块体尺寸的分布特征

通过不同装药结构下立方体红砂岩小型爆破实验,分析了岩石的损伤程度和破坏模式,同时引入三参数极值分布函数量化岩石爆破块体尺寸分布特征。此外,根据岩样R1的爆破实验结果进行了有限元数值模型验证,基于验证的模型展开了岩石单孔爆破损伤破裂行为的模拟,讨论了径向、轴向不耦合系数和耦合介质对岩石破碎效果的影响。结果表明,三参数极值分布函数可以较好地表征岩石爆破后破碎块体尺寸分布特征,块体平均尺寸随着不耦合系数的减小呈线性降低趋势,且破碎块度趋于均匀。通过比较不同耦合介质装药时岩石内部的能量分布特征和破坏体积发现,水作为耦合介质时,爆炸能量的传递效率最高,其次分别是湿砂和干砂,空气的能量传递效率最低。结合等效波阻法计算的理论应力透射系数可以很好地反映不耦合装药时岩石的破碎程度。

基于台区电能量分层级解耦的电能表远程在线校准

针对电能表元件稳定性较差的问题,提出基于台区电能量分层级解耦的电能表远程在线校准方法。根据台区电能量分层级精准解耦原则,设置典型分层端口结构,求解微分解耦数据方程,实现对电能系数的计量处理。分别从AD转换器量化误差、数值求积截断误差、同步误差三个角度着手,分析校准参量的取值结果,完成远程在线校准设计。实验结果表明:采用所提方法的总线电能表示数、支线电能表示数与理想示数之间的差值水平均能得到较好控制,与三轴同步校准方法相比,更符合维持电能表示数稳定性的实际应用需求。

虚拟母线式多端无线能量互联系统混合式多线圈结构设计与效率优化

在面向区域型电能互联应用的虚拟交流母线式多端无线能量互联系统中,双极型线圈较低的耦合系数会导致母线侧线圈损耗过高,系统效率偏低。为此,该文提出一种混合式线圈结构,即利用平面方形线圈替代原来单一式结构中的部分双极型线圈,在保证多线圈交叉解耦的前提下提高耦合系数。在该结构的基础上,对系统参数展开优化设计。基于线圈拆分与等效的思想,提出一种统一化线圈建模方法,以此获取最大效率下线圈匝数、补偿电感和母线电流幅值的最优取值。最后,搭建四端口原理样机验证所提线圈结构和参数优化设计的有效性,优化后的系统其在不同运行模式下的效率均提升8%以上。

长江经济带中三角三省碳排放及脱钩分析——基于2011—2020年省际面板数据

碳减排是人类共同面对的世界级难题。论文利用2011—2020年长江经济带中三角湘鄂赣三省相关省际面板数据,采用泰尔指数、Tapio模型等方法,分析了中三角三省碳排放趋势及脱钩现状。研究表明:(1)2011—2020年,江西、湖北和湖南的碳强度分别下降了48.22%、66.15%和51.01%,能源强度则分别下降了31.02%、59.37%和52.15%。得益于碳强度的下降和能源效率的提升,中三角碳排放量变化不大,区域碳排放和经济增长均衡性得以增强。(2)中三角三省主要处于碳弱脱钩状态,没有负脱钩和复挂钩的现象出现。(3)三省能源消费总量增量不多,能源结构降“碳”明显,江西、湖北和湖南煤炭消耗量占比分别下降到40.81%、37.33%和44.75%,非化石能源占比分别提高到31.23%、27.02%和26.70%。建议三省加强产业规划合作布局,完善以长江为主轴,赣江、汉江和湘江为补充的水运航道系统,强化清洁能源生产能力,最终促进三省经济发展形成绿色低碳新格局。

基于小波分层解耦的氢燃料电池复合电源拖拉机能量管理策略

针对单一能量系统无法充分发挥其优势,无法较好满足拖拉机作业时随机载荷谱密度大的问题,设计了基于氢燃料电池、动力电池、超级电容并联的电动拖拉机复合式能量系统.基于Haar小波与逻辑门限规则的分层解耦控制能量管理策略,实现了负载需求功率的高频信号、次高频信号、稳态信号的分层解耦,并对解耦后的功率信号进行功率分配.进行了模型在环仿真测试,结果表明:与功率跟随式控制策略及模糊控制策略相比,所建立的分层解耦控制策略氢燃料电池平均效率在试验循环内分别提高了2.85%、1.21%,整车等效氢气消耗量分别降低了16.11%、6.88%.本控制策略可以在满足整车负载需求功率的基础上提高整车经济性,并使燃料电池以高效平稳的工作状态输出功率.

Simple electrode assembly engineering:Toward a multifunctional lead-acid battery

Electrochemical energy storage is a promising technology for the integration of renewable energy.Lead-acid battery is perhaps among the most successful commercialized systems ever since thanks to its excellent cost-effectiveness and safety records.Despite of 165 years of development,the low energy density as well as the coupled power and energy density scaling restrain its wider application in real life.To address this challenge,we optimized the configuration of conventional Pb-acid battery to integrate two gas diffusion electrodes.The novel device can work as a Pb-air battery using ambient air,showing a peak power density of 183 mW cm^(−2),which was comparable with other state-of-the-art metal-O_(2)batteries.It can also behave as a fuel cell,simultaneously converting H_(2)and air into electricity with a peak power density of 75 mW cm^(−2).Importantly,this device showed little performance degradation after 35 h of the longevity test.Our work shows the exciting potential of lead battery technology and demonstrates the importance of battery architecture optimization toward improved energy storage capacity.

含能量路由器的交直流混合配电网潮流计算

能量路由器(energy router,ER)作为新兴电力电子设备,可以实现电能在电力系统中的灵活分配。分析ER对系统的影响,研究以ER为配电枢纽的交直流混合配电网潮流计算方法,对实现配电网的优化运行具有重要意义。文中首先基于改进交替迭代法建立ER的稳态潮流模型,并对ER直流端口采用下垂控制策略,结合传统解耦法,提出一种适用于含ER的配电网交直流解耦迭代潮流计算方法。以含有多个ER的IEEE 14节点和IEEE 69节点配电系统为算例进行仿真计算,验证所提方法的正确性与收敛性。为分析ER对系统运行的影响,对不同场景下IEEE 69节点测试系统进行仿真计算,证明ER在系统中可以支撑节点电压,减小系统运行损耗。

Fully Decoupled Branch Energy Balancing Control Method for Modular Multilevel Matrix Converter Based on Sequence Circulating Components

The modular multilevel matrix converter(M3C)is a potential frequency converter for low-frequency AC transmission.However,capacitor voltage control of high-voltage and largecapacity M3C is more difficult,especially for voltage balancing between branches.To solve this problem,this paper defines sequence circulating components and theoretically analyzes the influence mechanism of different sequence circulating components on branch capacitor voltage.A fully decoupled branch energy balancing control method based on four groups of sequence circulating components is proposed.This method can control capacitor voltages of nine branches in horizontal,vertical and diagonal directions.Considering influences of both circulating current and voltage,a cross decoupled control is designed to improve control precision.Simulation results are taken from a low-frequency transmission system based on PSCAD/EMTDC,and effectiveness and precision of the proposed branch energy balancing control method are verified in the case of nonuniform parameters and an unbalanced power system.