Design of Real Time Battery Management Unit for PV-Hybrid System by Application of Coulomb Counting Method

This paper presents a real-time battery management unit designed by applying the Coulomb counting method and intended for use in an integrated renewable energy system for PV-Hybrid power supply. Battery management is required to stabilize hybrid systems and extend battery lifetimes. The battery management unit is divided into three main stages. Firstly, analysis of the basic components of the battery type used in the system is considered. Secondly, the state of charge (SOC) estimation method and the deterioration factor of the battery are analyzed. Finally, the overall battery management system, including a computer-based measurement and control unit, is constructed. The control system displays real-time information through LabVIEW 8.5 by estimating the state of charge through various measurements. The system will issue alerts when malfunctions are detected, and the operator can analyze and react to the system in real time to stabilize the system and extend the battery lifetime.

Implementation of FPGA Based MPPT Techniques for Grid-Connected PV System

Global energy demand is growing rapidly owing to industrial growth and urbanization.Alternative energy sources are driven by limited reserves and rapid depletion of conventional energy sources(e.g.,fossil fuels).Solar photovol-taic(PV),as a source of electricity,has grown in popularity over the last few dec-ades because of their clean,noise-free,low-maintenance,and abundant availability of solar energy.There are two types of maximum power point track-ing(MPPT)techniques:classical and evolutionary algorithm-based techniques.Precise and less complex perturb and observe(P&O)and incremental conduc-tance(INC)approaches are extensively employed among classical techniques.This study used afield-programmable gate array(FPGA)-based hardware arrange-ment for a grid-connected photovoltaic(PV)system.The PV panels,MPPT con-trollers,and battery management systems are all components of the proposed system.In the developed hardware prototype,various modes of operation of the grid-connected PV system were examined using P&O and incremental con-ductance MPPT approaches.

基于RPC的光储接入牵引供电系统协调控制方法

为将光伏发电接入牵引供电系统进行有效利用,同时兼顾牵引供电系统电能质量改善及列车再生制动能量回收利用,提出了一种基于铁路功率调节器的光储系统接入牵引供电系统的协调控制方法.首先,搭建基于铁路功率调节器的光储系统接入牵引供电拓扑结构,并对其电能质量补偿机理进行理论分析;在此基础上,充分考虑光储系统的运行条件以及列车牵引、制动、空载或惰行工况,提出光储系统接入牵引供电的联合协调控制方法,实现了“光+储+荷”三者间的协调控制、牵引供电系统负序的动态补偿以及谐波的有效抑制;在RT-Lab实时仿真系统中建立了基于铁路功率调节器的光伏接入牵引供电系统仿真模型,并结合实际光照和牵引工况数据验证本文所提出的系统结构以及协调控制方法的有效性.结果表明:本文所提出的系统结构以及协调控制方法能够实现牵引供电系统中光储系统的有效接入,再生制动能量回收率提升至86.7%,功率因数提升6.4%,对谐波特别是高次谐波含有率有较大改善,满足光伏电能高效消纳及综合利用、电能质量动态综合补偿、再生制动能量回收多重需求.

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。

电动汽车与电网互联技术在新能源并网中的应用

V2G (Vehicle-to-Grid,电动汽车与电网互联)技术的应用可以实现电网与车主的双赢。从电网角度,可以发挥削峰填谷、平抑新能源功率波动、延缓电网升级改造等作用;从用户角度,在满足用车的要求下可获取附加效益。随着电动汽车的推广和新能源并网规模的发展,V2G技术得到更多的关注。然而,V2G技术的发展仍然面临规模化互动、运营、调度等技术及经济性问题。因此,从V2G技术发展的现状出发,重点阐述V2G技术在新能源并网中的作用和应用模式;并对V2G技术在新能源并网中的充放电策略、电池寿命预测以及综合价值进行了探讨。V2G技术在新能源并网中的推广应用不仅可以提升新能源并网利用率,还可进一步提升电动汽车的减排效果。

An Analytical Method for Delineating Feasible Region for PV Integration Capacities in Net-zero Distribution Systems Considering Battery Energy Storage System Flexibility

To provide guidance for photovoltaic(PV)system integration in net-zero distribution systems(DSs),this paper proposes an analytical method for delineating the feasible region for PV integration capacities(PVICs),where the impact of battery energy storage system(BESS)flexibility is considered.First,we introduce distributionally robust chance constraints on network security and energy/carbon net-zero requirements,which form the upper and lower bounds of the feasible region.Then,the formulation and solution of the feasible region is proposed.The resulting analytical expression is a set of linear inequalities,illustrating that the feasible region is a polyhedron in a high-dimensional space.A procedure is designed to verify and adjust the feasible region,ensuring that it satisfies network loss constraints under alternating current(AC)power flow.Case studies on the 4-bus system,the IEEE 33-bus system,and the IEEE 123-bus system verify the effectiveness of the proposed method.It is demonstrated that the proposed method fully captures the spatio-temporal coupling relationship among PVs,loads,and BESSs,while also quantifying the impact of this relationship on the boundaries of the feasible region.

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.

适用于光储氢集站的运维管理系统架构设计与研究

由于电池储能和电解水制氢在可再生能源消纳上具有促进作用,因此含有光伏、储能、电制氢装置等环节的光储氢集站正成为一类新兴的可再生能源开发形式。为此,研究了一套适用于光储氢集站的运维管理系统,实现对集站的发电量、并网功率、制氢功率、光伏功率、储能充放电等关键指标的实时监视,便于运维人员快速掌握全站运行情况。

并网型风光氢储微电网容量优化配置研究

本文以并网型风光氢储微电网为研究对象,在满足年制氢量任务的前提下建立了以系统年收益最大为目标的经济优化模型,对不同储能容量方案采用含罚函数的粒子群算法进行优化调度求解。最后对液态金属电池、液态金属电池-铅酸电池、锂电池、锂电池-铅酸电池四种储能配置方案进行对比研究,发现液态金属电池现阶段因价格高单独使用时优势不明显,而在混合储能系统中可以与铅酸电池优势互补。

塔式太阳能热发电站的定日镜无线控制自持系统研究进展

太阳能热发电技术受益于热能的可存储性,相较于光伏发电技术,其具备更好的调峰、调度及储能能力。综述了国内外在塔式太阳能热发电站的定日镜无线控制自持系统方面的研究进展,在无线控制系统方面,从安全性、传输距离及经济性角度重点比较了ZigBee、射频、蓝牙、Wi-Fi等无线通信技术,以及星型、树状、网状、环状等不同网络拓扑结构;在自持系统的供电方式方面,对光伏组件的不同安装方式,以及储能电池的类型选择和使用寿命预测进行了详细阐述。此外,简要论述了塔式太阳能热发电站的定日镜无线控制自持系统未来技术发展需考虑的方向。为塔式太阳能热发电站的定日镜无线控制自持系统的设计和优化提供了全面的分析和建议,以期为太阳能热发电技术的发展和应用提供参考。

一种基于混合储能改善跟踪光伏发电出力特性方法的研究

光伏输出受天气影响具有较大波动性,若直接接入电网则会对电网的电能质量造成严重影响。为减轻光伏电站并网功率对电网的影响,提出了一种基于氢与电池混合储能改善跟踪光伏发电出力特性的方法。首先,利用高斯函数逼近光伏预测功率,形成光伏次日出力计划,并根据次日凌晨电池SOC大小和氢储能调节灵活性对出力计划进行修正。考虑氢储能和电池储能运行状态,设计了包含有主调度和协调调度的实时调度方案。最后,通过算例验证了所提方法的有效性。

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。

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。

RPC接入牵引供电系统的无功补偿及谐波治理

铁路功率调节器(Railway Power Conditioner,RPC)既能作为光储系统接入牵引供电系统的端口,也能够有效解决柔性牵引供电系统中谐波及无功等电能质量问题。文章提出了一种考虑动态特性的RPC接入型柔性高速铁路牵引供电系统无功补偿及谐波治理方法。分析了牵引供电系统负序电流成因及RPC的基本工作原理,搭建了基于RPC接入的含光储柔性牵引供电系统,并开展了仿真分析。结果表明,所提出的考虑动态特性的RPC接入型柔性高速铁路牵引供电系统无功补偿及谐波治理方法,能够在电压、电流、功率因数、不平衡电流方面显著改善牵引供电系统的电能质量问题,提升系统的动态特性。

Numerical Modeling and Technico-Economic Analysis of a Hybrid Energy Production System for Self-Consumption: Case of Rural Area in the Comoros

This study aims to provide electricity to a remote village in the Union of Comoros that has been affected by energy problems for over 40 years. The study uses a 50 kW diesel generator, a 10 kW wind turbine, 1500 kW photovoltaic solar panels, a converter, and storage batteries as the proposed sources. The main objective of this study is to conduct a detailed analysis and optimization of a hybrid diesel and renewable energy system to meet the electricity demand of a remote area village of 800 to 1500 inhabitants located in the north of Ngazidja Island in Comoros. The study uses the Hybrid Optimization Model for Electric Renewable (HOMER) Pro to conduct simulations and optimize the analysis using meteorological data from Comoros. The results show that hybrid combination is more profitable in terms of margin on economic cost with a less expensive investment. With a diesel cost of $1/L, an average wind speed of 5.09 m/s and a solar irradiation value of 6.14 kWh/m2/day, the system works well with a proportion of renewable energy production of 99.44% with an emission quantity of 1311.407 kg/year. 99.2% of the production comes from renewable sources with an estimated energy surplus of 2,125,344 kWh/year with the cost of electricity (COE) estimated at $0.18/kWh, presenting a cost-effective alternative compared to current market rates. These results present better optimization of the used hybrid energy system, satisfying energy demand and reducing the environmental impact.

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。

Optimal configuration strategy of energy storage system in high photovoltaic penetration micro-grid based on voltage sensitivity analysis

Energy storage is an effective measure to deal with internal power fluctuation of micro-grid and ensure stable operation, especially in the micro-grid with high photovoltaic(PV) penetration. Its capacity configuration is related to the steady, safety and economy of micro-grid.In order to improve the absorptive capacity of micro-grid on maximizing the use of distributed PV power in micro-grid, and improve the power quality, an optimal energy storage configuration strategy is proposed, which takes many factors into account, such as the topology of micro-grid, the change of irradiance, the load fluctuation and the cable. The strategy can optimize the energy storage allocation model to minimize the storage power capacity and optimize the node configuration.The key electrical nodes are identified by using the sensitivity coefficient of the voltage, and then the model is optimized to simplify calculation. Finally, an example of the European low-voltage micro-grid and a micro-grid system in the laboratory is used to verify the effectiveness of the proposed method.The results show that the proposed method can optimize the allocation of capacity and the node of the energy storage system.

Optimal Design of Photovoltaic–Battery Systems Using Interval Type-2 Fuzzy Adaptive Genetic Algorithm

Many countries have been triggered to provide a new energy policy which promotes renewable energy applications because of public awareness to reduce the global warming and rising in fuel prices. Renewable energy sources such as solar energy are green and promising energy in the future for widespread use. Combining renewable energy sources with battery makes electricity supply more economical and reliable to meet all possible load level. This paper proposed a new hybrid method to optimize Photovoltaic (PV)-Battery systems. The proposed method was named Interval type-2 fuzzy adaptive genetic algorithm (IT2FAGA). Genetic algorithm (GA) is one of modern optimization techniques that has been successfully applied in various areas of power systems. To enhance the ability of GA to prevent trapping in? local optima and increase convergence in a global optima, the crossover probability (pcross) and the mutation probability (pmut), parameters in GA, are tuned using interval type-2 fuzzy logic (IT2FL). Objective function used in this paper was the annual cost of sytem (ACS) consisting of the annual capital cost (ACC), annual replacement cost (ARC), annual operation cost maintenance (AOM). The proposed method was also compared to fuzzy adaptive genetic algorithm (FGA) and standard genetic algorithm (SGA). Simulation results indicated that the

Power Quality Study of an Isolated Northwest Grid of Saudi Arabia with PV and Storage

One main concern of power quality is harmonics because the distorted waveforms of current and voltage have a huge effect on electrical equipment. Due to the continuous increase of grid connected photovoltaic (PV) and nonlinear loads, as a result of the fast development and growth of power electronics application, power quality becomes more important since it introduces harmonics to the power system. This paper presents a power quality study to the isolated northwest grid of Saudi Arabia in presence of PV system and battery storage. Moreover, the study includes nonlinear loads for more analysis regarding harmonics penetration and the design procedure for passive filters to eliminate the harmonics.

Economic Performance Optimization of a PV-BESS Power Generator: A Case Study La Reunion Island

This paper proposes an economic performance optimization strategy for a PV plant coupled with a battery energy storage system. The case study of La Reunion Island, a non-interconnected zone (NIZ) with a high level of renewable energy sources (RES), is considered. This last decade, to reach the ambitious target of electricity autonomy by 2030 set by the local authorities, local and national plans have been launched to promote renewable energy sources integration that led to a noticeable development of photovoltaic (PV) systems. To avoid a decrease of the grid reliability due to a large integration of intermittent energy sources into a non-interconnected grid, the authorities have introduced new regulatory rules for RES producers. The proposed optimization strategy relies on these new regulatory rules and takes into account the energy market data, the amount of PV production subject to penalties for imbalance, the batteries and the PV technological characteristics together with a PV production forecast model. Due to its high convergence rate to the true global minimum and its perfect suitability to practical engineering optimization problems, the recently developed Modified Cuckoo Search algorithm is used as optimization algorithm. The effectiveness and relevance of the proposed strategy are assessed on experimental data collected on a real PV power plant. An economical analysis demonstrates that the proposed optimization strategy is able to fulfill the new regulatory rules requirements while increasing the economic performance of the system.