基于改进高斯滤波器的含锁相环PV-BES微电网的孤岛检测和无缝切换控制

该文提出了一种基于锁相环(PLL)的电网监测和无缝传输控制的改进高斯滤波器,用于改善含光伏电池储能(PVBES)微电网的电能质量。在并网模式下,该文提出了一种基于正交信号发生器的二阶广义积分器(QSG-SOGI)前置滤波的改进高斯滤波器,已实现MG向非线性负载和主网提供电能,同时在公共耦合点(PCC)给电网提供无功功率补偿和电能质量改善。此外,光伏前馈项可实现光伏功率注入调节,也可改善系统的动态特性;在电网故障时,控制器将PV-BES微电网转换为孤岛运行模式,可确保不间断地向负荷供电。最后,在各种场景下该文对所提控制器的有效性和优越性进行了测试,并通过实验进行了验证。

PV-Hybrid Off-Grid and Mini-Grid Systems for Rural Electrification in Sub-Saharan Africa

Rural electrification remains a great challenge for Sub-Saharan Africa (SSA) as access to electricity is a prerequisite to accelerate its development. The present paper reviews the measures adopted to promote access to electricity in rural and remote areas of SSA. The main barriers to rural electrification in these developing countries are presented before showing technologies used for the aforementioned purpose. Then, adopted methods for enhancing the use of renewable energy in SSA are shown. Moreover, the policy adopted by decision makers and project planners are also highlighted. In addition, the optimal solutions proposed by researchers are given such as the cost-effective off-grid system type that might be a viable alternative to diesel power generation.

Short-term Distributed Energy Resource Scheduling for a DC Microgrid

A microgrid is associated with a low voltage distribution power network and inherits small modular generation systems and loads that have certain coordinated functions to provide the solution to supply premium power to remote or specific areas. Similar to conventional power systems, the energy management of distributed generation resources (DERs) is carried out to minimize the operation cost and maximize benefit of installation of DERS in a microgrid. This paper presents the process of implementing the short-term DER scheduling function for a dc microgrid. The optimal scheduling results for two operation modes are then reported.

基于光伏热PV/T冷热电联产的研究

分析冷热电联供优化设计研究现状,研究光伏半导体硅电池。通过MATLAB仿真显示了温度对光伏电池光电转化效率的重大影响。在此基础上,引出了PV/T光伏光热一体化组件,提出了一种改进型的光伏冷热电联供微电网模型。构建了一个5 MW的光伏微电网社区。由于天然气不可再生,该系统内只使用太阳能发电,实现节能减排。建立多目标下的优化函数,并结合具体算例,分析了夏季冬季典型日优化运行方案。

Feasibility Analysis of an Islanded Microgrid in Tohatchi, New Mexico Using HOMER Pro

Microgrids are becoming more popular in areas where there is still no connectivity to the main grid largely due to their remote geographical location. This paper focuses on the feasibility analysis, using the HOMER Pro simulation program, of an islanded micro-grid for the Navajo community in Tohatchi, New Mexico using different energy mixes of a Photovoltaics (PV) system, a Wind Energy system, a Battery Energy Storage System (BESS) and a Diesel Generator. The Net Present Cost (NPC), and the Levelized Cost of Electricity (LCOE), were the two crucial economic factors considered. Through the analysis, the system with the PV, wind turbines, battery, and a diesel generator was found to have the lowest LCOE and NPC. There was a reduction of 75% in the costs of the combined system as compared to the diesel-only base case. Also, this combined system provided the minimum emission levels. The analysis suggests that the integration of renewable energy using microgrids to help the access of energy for rural areas was possible. The analysis could very well be extended to any other community by considering the wind and solar resources present at that location.

Optimal Scheduling of PEV Charging/Discharging in Microgrids with Combined Objectives

While renewable power generation and vehicle electrification are promising solutions to reduce greenhouse gas emissions, it faces great challenges to effectively integrate them in a power grid. The weather-dependent power generation of renewable energy sources, such as Photovoltaic (PV) arrays, could introduce significant intermittency to a power grid. Meanwhile, uncontrolled PEV charging may cause load surge in a power grid. This paper studies the optimization of PEV charging/discharging scheduling to reduce customer cost and improve grid performance. Optimization algorithms are developed for three cases: 1) minimize cost, 2) minimize power deviation from a pre-defined power profile, and 3) combine objective functions in 1) and 2). A Microgrid with PV arrays, bi-directional PEV charging stations, and a commercial building is used in this study. The bi-directional power from/to PEVs provides the opportunity of using PEVs to reduce the intermittency of PV power generation and the peak load of the Microgrid. Simulation has been performed for all three cases and the simulation results show that the presented optimization algorithms can meet defined objectives.

Optimal Sizing of Solar/Wind Hybrid Off-Grid Microgrids Using an Enhanced Genetic Algorithm

This paper presents a method for optimal sizing of an off-grid hybrid microgrid (MG) system in order to achieve a certain load demand. The hybrid MG is made of a solar photovoltaic (PV) system, wind turbine (TW) and energy storage system (ESS). The reliability of the MG system is modeled based on the loss of power supply probability (SPSP). For optimization, an enhanced Genetic Algorithm (GA) is used to minimize the total cost of the system over a 20-year period, while satisfying some reliability and operation constraints. A case study addressing optimal sizing of an off-grid hybrid microgrid in Nigeria is discussed. The result is compared with results obtained from the Brute Force and standard GA methods.

基于SPEA2的风光柴储独立微电网多目标容量优化配置

在电力资源相对匮乏而自然风光资源丰富的孤岛等地区,电力供应的稳定性和成本效益一直是个亟待解决的问题。传统的独立微电网在容量配置时,大多依赖快速非支配排序遗传算法(NSGA-Ⅱ),该算法在处理真实负载的多目标优化问题时,局部搜索能力略显不足。为此,提出了利用改进强度Pareto进化算法(SPEA2)优化风光柴储独立微电网容量配置,以经济性成本、失负荷概率、碳排放作为优化目标,实现更加全面和高效的容量配置。通过导入某孤岛天气与负荷数据,生成风光柴储独立微电网的真实Pareto前沿,将SPEA2和基于指标选择的多目标搜索(IBEA)、NSGA-Ⅱ3种算法分析结果进行对比,相较于NSGA-Ⅱ,SPEA2的反世代距离评价IGD指标提升46.83%,空间评价方法Spacing指标提升60.28%,真实Pareto覆盖率CPF指标提升35.14%,该算法表现出更加出色的性能。最后根据容量优化的结果合理配置各部分参数,共同出力满足负荷需求,为孤岛等电力资源匮乏地区的能源管理提供了新的思路,也为多能源微电网的优化设计提供了有价值的参考。

含电动汽车的风光柴储独立型微电网容量优化配置

考虑电动汽车负荷的影响,提出了一种计及电动汽车的含风光柴储微电网容量优化配置方法。给出了微电网中负荷、风电、光伏系统、电池储能和柴油发电的建模方法,在考虑测试系统动态的情况下,以微电网系统总成本最小化为目标,采用灰狼算法对风机、光伏系统、电池储能和柴油发电机进行容量优化。以某实际17节点微电网为例进行仿真,仿真结果表明,微电网系统中的负荷尽可能通过分布式新能源来提供,有效减少了温室气体的排放,同时使微电网系统的总成本达到最小,系统按照所提方法优化设计,能够经济可靠地供应负荷。

基于直流母线电压信号的小型独立直流微电网自主平滑模式切换控制策略

在独立直流微电网中,储能系统(ESSs)和光伏(PV)是主要能源。在极端条件下,储能和光伏变换器需要进行工作模式切换以协调功率,为了优化切换性能,该文提出一种基于直流总线信号(DBS)的自主平滑模式切换控制策略,用于多个光伏电源和ESS的无通信协同工作,提高了系统的可靠性。针对多模式切换过程中的抖振和死锁问题,所提出的控制策略利用具有反馈抑制机制的PI控制器实现了在饱和与激活之间无缝切换。同时,为了进一步提升光伏能量的利用率,所提出的控制策略充分考虑了ESS的荷电状态(SOC),并使光伏电源能够直接参与直流母线电压的调节。此外,还对模式切换时间与控制器参数的设计进行了详细的分析建模,以优化模式切换性能。最后,建立了一个小型独立直流微电网实验系统,以验证所提出的直流微电网控制方法的可行性。

基于自然资源评价的独立微网电源优化配置

为了保证独立微网运行的经济性和可靠性,在进行独立微网规划时,首先要确认电源的优化配置.微网内部负荷水平、所在地区地理和气候等自然资源条件会影响独立微网电源类型和容量的选择.本文研究不同地区“风/光/水/储”的综合自然资源特性,考虑独立微网供电可靠性和发电环保性,建立以微网电源最小综合发电成本为目标,计及电力电量平衡等约束条件的优化模型,采用线性化算法求解.针对风机、光伏和水电出力的不确定性,研究生成对抗网络GAN,对风光水出力进行多场景模拟,采用K-Medoids聚类算法的改进方法,实现运行场景的削减,提高了计算效率.为了分析风光水资源特性,构建了风光水资源指标评价体系,基于模糊评价方法,获取我国内地地区31个省级行政区的风光水资源水平.选取5个代表地区,验证所提方法的可行性和合理性,分析地区独立微电网电源配置方案和电源配置规律,为独立微电网电源规划提供参考.

自适应下垂控制的多光伏源直流微网功率分配

现有直流微网下垂控制普遍采用固定下垂值,因此存在电压恢复能力差且无法应对瞬时电压的问题,为此提出一种自适应比例下垂指数控制的多光伏源直流微网功率分配策略。基于归一化电流分配差值和变流器输出侧电压偏差值的函数,引入比例下垂指数(PDI)算法实现对微网负荷的功率比例分配。在此基础上引入下垂电阻自适应更新策略,借助两个下垂校正因子实时更新下垂电阻值,以解决电压恢复能力差和瞬时电压跌落的问题,同时消除传统下垂控制在电流分配和电压调节之间的矛盾。最后搭建实验样机对所提方案进行验证,实验结果表明所提方案实现了微网负荷的比例分配和负荷电压的快速恢复,从而提高系统的整体性能。

工业园区微电网项目中风电与光伏发电的容量配置及推广策略研究

以工业园区微电网项目中的风电和光伏发电为研究对象,在考虑场址条件、资源情况和设备选型的情况下,分析了工业园区微电网项目中风电和光伏发电的容量配置方法,并根据经济性评价得到最优的风电和光伏发电容量配置方案;通过对包含中国4类风能资源区、4类太阳能资源区在内,处于不同地域且采用不同电价的15个典型城市的工业园区开发微电网项目进行经济性测算,以投资收益测算结果作为依据来评判此类项目中风电和光伏发电的投资价值,从而得到可执行的风电和光伏发电的推广策略。研究结果表明:1)小型风电机组的投资价值较差,只有在风能资源优且平段电价高的城市才适合应用;大型风电机组的投资价值较高,在园区不限高且安全距离足够的情况下,只有在风能资源差且平段电价低的城市才不适合应用;由于风能资源分布的不连续性,考虑工业园区微电网项目的风电投资时,仍需根据园区实际位置对其风能资源情况进行测算,以确定是否具备风电投资价值。2)光伏发电的盈利能力较好,投资价值较高,可以大力推广;但在太阳能资源较差或平段电价较低的城市,光伏发电不具备开发价值。研究结果可为未来工业园区的风电和光伏发电开发提供参考,并为新能源在工业园区的应用推广提供指导。

基于某“新城建”示范项目的“光储直柔”实践应用与研究

针对“光储直柔”这一新型建筑电力系统,以某办公示范项目为例,简要介绍项目电气机房设置及分布,着重解析系统光伏发电系统设计、储能系统设计、系统架构及直流配电设计,对系统的运行模式及柔性调控策略作较为详细的分析,并提出系统在建筑大规模应用存在的部分技术难点。

An Adaptive Control Strategy for Energy Storage Interface Converter Based on Analogous Virtual Synchronous Generator

In the DC microgrid,the lack of inertia and damping in power electronic converters results in poor stability of DC bus voltage and low inertia of the DC microgrid during fluctuations in load and photovoltaic power.To address this issue,the application of a virtual synchronous generator(VSG)in grid-connected inverters control is referenced and proposes a control strategy called the analogous virtual synchronous generator(AVSG)control strategy for the interface DC/DC converter of the battery in the microgrid.Besides,a flexible parameter adaptive control method is introduced to further enhance the inertial behavior of the AVSG control.Firstly,a theoretical analysis is conducted on the various components of the DC microgrid,the structure of analogous virtual synchronous generator,and the control structure’s main parameters related to the DC microgrid’s inertial behavior.Secondly,the voltage change rate tracking coefficient is introduced to adjust the change of the virtual capacitance and damping coefficient flexibility,which further strengthens the inertia trend of the DC microgrid.Additionally,a small-signal modeling approach is used to analyze the approximate range of the AVSG’s main parameters ensuring system stability.Finally,conduct a simulation analysis by building the model of the DC microgrid system with photovoltaic(PV)and battery energy storage(BES)in MATLAB/Simulink.Simulation results from different scenarios have verified that the AVSG control introduces fixed inertia and damping into the droop control of the battery,resulting in a certain level of inertia enhancement.Furthermore,the additional adaptive control strategy built upon the AVSG control provides better and flexible inertial support for the DC microgrid,further enhances the stability of the DC bus voltage,and has a more positive impact on the battery performance.

基于事件触发的直流微电网无差拍预测控制

针对光伏(Photovoltaic, PV)-电池-超级电容直流微电网系统中光伏发电间歇性造成的功率失配问题,提出一种基于事件触发的无差拍预测控制(Event-triggered deadbeat predictive control, ETDPC)方法,以实现有效的能量管理. ETDPC方法结合事件触发控制策略和无差拍预测控制策略(Deadbeat predictive control, DPC)的优点,根据微电网的拓扑结构构建状态空间模型,用于设计适用于微电网能量管理的触发条件:当ETDPC的触发条件满足时, ETDPC中无差拍预测控制模块被激活,可以在一个控制周期内产生最优控制信号,实现对于扰动的快速响应,减小母线电压纹波;当系统状态不满足ETDPC中的触发条件时,无差拍预测控制模块被挂起,从而消除非必要运算,以减轻实现能量管理的运算负担.因此,对于电池-超级电容器混合储能系统(Hybrid energy storage system, HESS), ETDPC能够缓解间歇性光伏发电与负荷需求之间的功率失衡,以稳定母线电压.最后,数字仿真和硬件在环(Hardware-in-loop, HIL)实验结果表明,相较于传统无差拍控制方法,运算负担减小了50.63%,母线电压纹波小于0.73%,验证了ETDPC方法的有效性与性能优势,为直流微电网的能量管理提供了一种参考.

某机修工程光储直柔系统方案探讨

在分析光储直柔系统原理基础上,以某新建机修工程智慧低碳建筑为例,构建光储直柔微网系统和光储充微网系统,并对两种方案进行设计对比分析探讨,以实现新能源的更好利用。

风-光-柴-储微电网能量管理的日前优化调度策略分析

针对风-光-柴-储微电网能量管理日前优化调度问题展开研究。首先,介绍了风-光-柴-储微电网结构,并建立各发电部分的输出功率和成本模型;其次,以总运行成本最低为目标函数制定微电网能量管理日前优化调度策略,并建立相应模型;最后,以某算例进行能量管理日前优化调度策略效果验证。验证结果显示:通过采用所提出的能量管理日前优化调度策略,可以满足用户的日常负荷要求,同时所配置的储能系统可以最大限度的存储可再生能源系统多余的发电量,最大程度地避免了弃电,并减少了柴油发电系统的使用率,降低了对环境的伤害,可满足微电网的能量管理目标;验证了策略的经济性与可靠性。

风光储直流微电网的双输入MPPT控制策略分析

针对以输出功率为判断标准的传统的单输入扰动观察法(下文简称为“传统扰动观察法”)存在的弊端,提出一种可用于风光储直流微电网的双输入变步长扰动观察法(下文简称为“双输入MPPT控制策略”),并对风电机组和光伏发电系统分别采用两种控制策略时的占空比、发电效率等进行了对比分析。分析结果显示:相较于传统扰动观察法,风电机组采用双输入MPPT控制策略追踪最大功率点后,扰动步长减小90%的同时追踪时间减少了72.3%;光伏发电系统采用双输入MPPT控制策略追踪最大功率点后,扰动步长减小90%的同时追踪时间减少了39%。仿真结果验证了双输入MPPT控制策略的有效性,该策略适用于电感参与调压的多种场景。

工业用光伏微网运行策略优化与经济性分析

针对工业用户,以工业用光伏微网系统为研究对象提出了运行策略优化和经济性分析方法。所考虑的经济性指标包括单位电能成本、污染物减排收益和投资回收期;运行策略的优化考虑了不同的并网策略、是否配置储能单元、当地太阳辐射强度等环境因素和系统建设、运行中的各种具体成本,以进一步提高系统的经济性及其带来的污染物减排收益。算例以安装在广东的一个500kW工业用光伏微网系统连续3个月的运行数据为基础进行仿真分析,结果表明经过优化的储能系统的加入有效地提高了系统的经济性和环境效益,同时系统参与大电网削峰填谷的能力也得到了增强。此外,本文也研究了不同参数的敏感性分析和不同安装地点对系统经济性的影响。研究结果对于设计类似的工业用光伏微网系统提供了一定的借鉴并为光伏微网系统的决策者提供决策基础。