基于余弦平顶窗的谐波相量测量

In this paper, a Backstepping Global Integral Terminal Sliding Mode Controller (BGITSMC) with the view to enhancing the dynamic stability of a hybrid AC/DC microgrid has been presented. The proposed approach controls the switching signals of the inverter, interlinking the DC-bus with the AC-bus in an AC/DC microgrid for a seamless interface and regulation of the output power of renewable energy sources (Solar Photovoltaic unit, PMSG-based wind farm), and Battery Energy Storage System. The proposed control approach guarantees the dynamic stability of a hybrid AC/DC microgrid by regulating the associated states of the microgrid system to their intended values. The dynamic stability of the microgrid system with the proposed control law has been proved using the Control Lyapunov Function. A simulation analysis was performed on a test hybrid AC/DC microgrid system to demonstrate the performance of the proposed control strategy in terms of maintaining power balance while the system’s operating point changed. Furthermore, the superiority of the proposed approach has been demonstrated by comparing its performance with the existing Sliding Mode Control (SMC) approach for a hybrid AC/DC microgrid.     

多源多变换微电网系统建模与动态稳定分析方法

微电网内部电力电子变换器接口型分布式电源广泛存在.电力电子接口微源具备与传统电力系统电源拓扑结构、控制方法和动态特性的差异性,控制方法的多样性、电力电子接口微源高渗透率将给低惯量微电网的协调控制和安全稳定运行带来严峻的挑战.多类型微源、多类型负荷在微电网内混合共存,可能引发源源耦合交互、负荷间交互以及源荷交互,不同特性的设备间相互作用将重新塑造区别与传统电力系统的动态响应特性,并诱发稳定性问题.本文首先归纳总结可再生能源渗透率不断提升下多源多变换微电网典型运行特性和存在的稳定性问题,详细阐述了含风光柴储多源多变换接口的微电网模块化动态建模方法.在此基础上,给出了用于微电网动态稳定分析的特征值分析方法和基本步骤.以珠海东澳岛多源多变换智能微电网为对象,基于提出的动态建模方法和动态稳定分析方法,给出建模与分析讨论结果.论文对多源多变换微电网系统动态稳定分析方法的论述可为微电网的广泛推广和应用提供建模和分析理论基础.     

直流微电网分布式控制的时滞稳定化设计

直流微电网中,大部分控制器在设计时未考虑通信延时对系统性能的影响,这可能会导致控制器在实际应用中失效甚至影响系统的稳定性.本文基于一种分布式控制策略,建立了直流微电网系统的时滞模型,重点研究了通信延时对系统稳定性的影响.结合Razumikhin稳定性理论,提出了一种针对时变时滞系统的全时滞稳定性判据.为了更加适用于实际系统,在另一种全时滞稳定性判据的基础上,对系统时滞相关稳定性进行分析,得到保证系统稳定的延时上界,进而给出了一种确定控制参数范围的方法.与传统的将通信延时处理为一阶惯性环节的分析方法相比,基于时滞系统的分析方法更切合实际,为系统的稳定运行提供了一个更宽的时滞范围,提高了系统的可靠性.仿真和实验结果表明本文提出的控制参数设计方法能保证系统在最大延时下的稳定运行.     

Transactive energy management for optimal scheduling of interconnected microgrids with hydrogen energy storage

In recent years, renewable energy sources (RESs) have attracted substantial attention due to carbon-free and cost-effective advantages that have made them one of the main sources of energy generation in the modern structure of the power grid. This paper proposes the stochastic day-ahead scheduling model for optimal energy management of renewable-based microgrids. In this paper, each microgrid is equipped with 100% RESs including the PV system and wind turbine for full pollutant-free energy generation while the hydrogen energy storage (HES) system is used for alleviating the intermittences of the RESs aiming to dynamically balance the energy during a day. To model the fluctuations such as day-ahead market price in the microgrids, the autoregressive integrated moving average and fast forward selection methods are exerted for scenario production and reduction, respectively. Transactive energy as a sustainable and reliable technique is considered for controlling and coordinating energy sharing among the microgrids and the energy network for dynamic energy balancing in the deregulated environment. For energy management in the demand-side, the price and load response schemes are presented, aiming to revise the consumers' patterns in energy consumption in line with balancing energy and minimizing the microgrids’ energy cost. The effectiveness of the suggested model is validated using the modified IEEE 24-bus case study. The realistic modeling of the system based on the proposed model has led to an 8.51% increment in energy cost.     

改进状态抽样法及其在含微网配电网风险评估中的应用

研究了配电网短期风险评估的方法以及微网配置对配电网风险指标的影响。系统状态选择采用改进的状态抽样法,简化抽样过程的同时兼顾系统的时序性,所用负荷和新能源电源出力模型能方便刻画其随时间的波动性。采用最小时段分割的方法精确统计停电时间、停电电量等状态后果,结合改进抽样法的特点,用综合计及概率与后果的电量类和经济类风险指标评估系统风险。以改造的RBTS BUS6 系统为例进行24 h短期风险评估,结果反映微网的接入可在一定程度上降低配电网的失电风险。     

考虑灵活性供需匹配的孤岛微网优化调度策略

为使孤岛微网能更大程度地实现源侧发电功率与荷侧用电需求之间的匹配程度,以灵活性理论为依据,提出考虑灵活性供需匹配的优化调度模型。以最大化经济效益和最大化灵活性供需匹配程度为目标,利用多目标粒子群优化算法得到该优化问题的Pareto解集,并从中选取更符合实际需求的解。算例仿真结果表明,所提优化调度策略能有效提升系统应对可再生能源发电机组出力的波动性与随机性的能力,提高经济效益。     

计及天然气压力能的微电网储荷协调优化调度

为解决天然气输送过程中压力能的浪费问题,提高天然气能源利用率,提出将天然气压力能发电系统引入至微电网整体调度方案中。针对天然气压力能发电系统中前后端口的补热需要,将微电网中的风冷热泵补热系统与压力能发电系统进行耦合。考虑到由天然气管网中流量波动和环境因素造成的压力能出力波动问题,提出微电网储荷一体化协调优化方案,以确保系统高效稳定运行。基于上述内容,构建考虑可控电源出力成本、储能调度成本、微电网与配电网的交互成本和负荷调度成本的微电网优化调度模型,并采用Yalmip工具包编写优化调度程序。最后,通过对西南地区某调压站数据进行仿真,验证该方案的可行性与经济性。     

风光柴储微电网容量优化配置的运行策略

设计合理的运行策略是微电网容量优化配置过程中的关键因素之一。以典型独立型风光柴储微电网为研究对象,基于分布式电源的特征,将微电网运行工况划分为7种状态,进而找出设计运行策略的关键问题：当储能（BES）、柴油发电机（DE）的可输出最大功率之和大于净负荷功率时,如何分配净负荷。针对该关键问题提出首选BES分配净负荷、首选DE分配净负荷、DE趋向额定功率分配净负荷3种运行策略。基于解算多目标优化模型的计算结果分析3种运行策略的特点,指出各自的适用场合。     

Step-up Transformerless Seven-level DC-AC Hybrid Topology for Interconnection of Renewable-based DC Sources to Microgrids

This article introduces a new step-up transformerless multi-level DC-AC hybrid topology for interconnecting renewable DC sources to loads or microgrids. This enabling technology incorporates the best characteristics of three modified basic topologies—a DC-DC multi-level boost converter, a DC-DC multi-level buck converter, and an H-bridge—to obtain a seven-level step-up DC-AC hybrid structure using only one DC input and nine power switches for a single-phase output with field-programmable gate array based control. The advantages of the step-up seven-level structure compared to other proposals are higher efficiency, a reduced number of power switches, and high power density associated with transformerless characteristic. Furthermore, in contrast to conventional topologies, the proposed design does not require voltage/current monitoring of the capacitors or a capacitor-balancing control scheme, and only one DC source input is used. Consequently, a high-performance configuration is obtained. The laboratory results demonstrate the validity of the design and the performance of the prototype.     

微电网中微型燃气轮机发电系统整体建模与仿真

微型燃气轮机发电系统能同时产生热能和电能,具有排放少、效率高、安装方便、维护简单等特点,成为热电联供微电网中最有发展前景的分布式电源.文中根据微型燃气轮机发电系统的动态特性,考虑基本的V/f和PQ控制策略,采用正弦脉宽调制(SPWM)逆变器,以"统一"模块化思想建立了微型燃气轮机发电系统的整体模型,并采用PSCAD/EMTDC软件,在动态负荷条件下对该微型燃气轮机发电系统进行仿真,分析了微型燃气轮机与电力电子变流装置及负荷之间的相互影响.仿真结果表明,所构建的系统模型的动态特性符合实际,为进一步研究微电网中各种分布式电源之间的协调控制奠定了基础.