Optimal Multi-Timescale Scheduling of Integrated Energy Systems with Hybrid Energy Storage System Based on Lyapunov Optimization

The economic operation of integrated energy system(IES)faces new challenges such as multi-timescale characteristics of heterogeneous energy sources,and cooperative operation of hybrid energy storage system(HESS).To this end,this paper investigates the multi-timescale rolling opti-mization problem for IES integrated with HESS.Firstly,the architecture of IES with HESS is established,a comparative analysis is conducted to evaluate the advantages of the HESS over a single energy storage system(SESS)in stabilizing power fluctuations.Secondly,the dayahead and real-time scheduling cost functions of IES are established,the day-ahead scheduling mainly depends on operation costs of the components in IES,the real-time optimal scheduling adopts the Lya-punov optimization method to schedule the battery and hydrogen energy storage in each time slot,so as to minimize the real-time average scheduling operation cost,and the problem of day-ahead and real-time scheduling error,which caused by the uncertainty of the energy storage is solved by online optimization.Finally,the proposed model is verified to reduce the scheduling operation cost and the dispatching error by performing an arithmetic example analysis of the IES in Shanghai,which provides a reference for the safe and stable operation of the IES.

Modeling and Simulation of a Hybrid Energy Storage System for Residential Grid-Tied Solar Microgrid Systems

Present-day power conversion and conditioning systems focus on transferring energy from a single type of power source into a single type of load or energy storage system (ESS). While these systems can be optimized within their specific topology (e.g. MPPT for solar applications and BMS for batteries), the topologies are not easily adapted to accept a wide range of power flow operating conditions. With a hybrid approach to energy storage and power flow, a system can be designed to operate at its most advantageous point, given the operating conditions. Based on the load demand, the system can select the optimal power source and ESS. This paper will investigate the feasibility of combining two types of power sources (main utility grid and photovoltaics (PV)) along with two types of ESS (ultra-capacitors and batteries). The simulation results will show the impact of a hybrid ESS on a grid-tied residential microgrid system performance under various operating scenarios.

Analysis of Hybrid Rechargeable Energy Storage Systems in Series Plug-In Hybrid Electric Vehicles Based on Simulations

In this paper, an extended analysis of the performance of different hybrid Rechargeable Energy Storage Systems (RESS) for use in Plug-in Hybrid Electric Vehicle (PHEV) with a series drivetrain topology is analyzed, based on simulations with three different driving cycles. The investigated hybrid energy storage topologies are an energy optimized lithium-ion battery (HE) in combination with an Electrical Double-Layer Capacitor (EDLC) system, in combination with a power optimized lithium-ion battery (HP) system or in combination with a Lithium-ion Capacitor (LiCap) system, that act as a Peak Power System. From the simulation results it was observed that hybridization of the HE lithium-ion based energy storage system resulted from the three topologies in an increased overall energy efficiency of the RESS, in an extended all electric range of the PHEV and in a reduced average current through the HE battery. The lowest consumption during the three driving cycles was obtained for the HE-LiCap topology, where fuel savings of respectively 6.0%, 10.3% and 6.8% compared with the battery stand-alone system were achieved. The largest extension of the range was achieved for the HE-HP configuration (17% based on FTP-75 driving cycle). HP batteries however have a large internal resistance in comparison to EDLC and LiCap systems, which resulted in a reduced overall energy efficiency of the hybrid RESS. Additionally, it was observed that the HP and LiCap systems both offer significant benefits for the integration of a peak power system in the drivetrain of a Plug-in Hybrid Electric Vehicle due to their low volume and weight in comparison to that of the EDLC system.

Towards Implementation of Smart Grid: An Updated Review on Electrical Energy Storage Systems

A smart grid will require, to greater or lesser degrees, advanced tools for planning and operation, broadly accepted communications platforms, smart sensors and controls, and real-time pricing. The smart grid has been described as something of an ecosystem with constantly communication, proactive, and virtually self-aware. The use of smart grid has a lot of economical and environmental advantages;however it has a downside of instability and unpredictability introduced by distributed generation (DG) from renewable energy into the public electric systems. Variable energies such as solar and wind power have a lack of stability and to avoid short-term fluctuations in power supplied to the grid, a local storage subsystem could be used to provide higher quality and stability in the fed energy. Energy storage systems (ESSs) would be a facilitator of smart grid deployment and a “small amount” of storage would have a “great impact” on the future power grid. The smart grid, with its various superior communications and control features, would make it possible to integrate the potential application of widely dispersed battery storage systems as well other ESSs. This work deals with a detailed updated review on available ESSs applications in future smart power grids. It also highlights latest projects carried out on different ESSs throughout all around the world.

考虑电池SOC一致性的城轨交通MHESS功率分配策略

在城市轨道交通中,通常采用多混合储能系统(MHESS)来解决列车在牵引和制动过程中所引起的牵引网络电压波动问题。该系统由超级电容器和锂电池组成,旨在平滑功率波动,实现“削峰填谷”。考虑到MHESS多个混合储能系统之间可能存在初始状态不一致的情况,提出一种考虑电池SOC一致性的RBF-PID控制策略,用于兼顾直流稳压特性以及电池储能系统寿命保护最优。由列车运行速度需求得到牵引功率需求,采用滑动平均滤波(MAF)算法将高频功率指令分配给超级电容,低频功率指令分配给电池与牵引网。进一步地,考虑到混合储能系统间初始状态不一致情况下的电池寿命保护问题,通过合理设计功率分配切换规则,在初始SOC较低电池的传统电压外环控制中引入基于电池SOC一致性的RBF-PID控制,合理控制电池的充放电电流,防止过冲、过放现象,从而延长电池寿命。为验证所提控制策略的有效性,使用Matlab/Simulink仿真软件进行仿真验证。实验结果表明,所提方法能够降低初始SOC较低电池的放电深度,有效保护储能元件。

Average Current Control with Internal Model Control and Real-time Frequency Decoupling for Hybrid Energy Storage Systems in Microgrids

Among hybrid energy storage systems(HESSs),battery-ultracapacitor systems in active topology use DC/DC power converters for their operations.HESSs are part of the solutions designed to improve the operation of power systems in different applications.In the residential microgrid applications,a multilevel control system is required to manage the available energy and interactions among the microgrid components.For this purpose,a rule-based power management system is designed,whose operation is validated in the simulation,and the performances of different controllers are compared to select the best strategy for the DC/DC converters.The average current control with internal model control and real-time frequency decoupling is proposed as the most suitable controller according to the contemplated performance parameters,allowing voltage regulation values close to 1%.The results are validated using real-time hardware-in-the-loop(HIL).These systems can be easily adjusted for other applications such as electric vehicles.

基于FCS-MPC的分布式HESS功率协调控制

针对孤岛直流微电网中分布式混合储能系统(HESS)协调运行问题,提出一种基于有限控制集模型预测控制(FCSMPC)的功率协调控制策略。该策略采用小波包变换来分解分布式HESS的功率需求,由于分解后信号的特点和分布式HESS中蓄电池初始状态的不同,于是对分解后最低频信号基于蓄电池荷电状态(SOC)设计自适应因数来进一步再分解。由于DC/DC变换器开关状态组合数量较少,使得多步FCS-MPC的滚动优化计算量较少,于是采用FCS-MPC取代双闭环PI控制,提高系统动态响应。搭建含有分布式HESS的孤岛直流微电网模型,并做了3种方案的仿真对比,验证该策略有效平缓了直流母线波动并实现蓄电池SOC一致。该策略有利于提高电网运行的稳定性,并延长蓄电池使用寿命。

基于EnergyPlus和Jeplus+EA联合模拟的建筑围护结构及光储系统协同优化研究

建筑本体和可再生能源系统的协同作用对于降低建筑碳排放具有重要意义.以北京某办公建筑为例,基于NSGA-Ⅱ的优化算法,以运行阶段碳排放和生命周期成本为目标函数,以热舒适为约束条件,利用EnergyPlus和Jeplus+EA软件进行联合仿真,开展建筑围护结构和光储系统的协同优化研究.结果表明:配置光储系统可较大程度降低建筑电网购电量及运行阶段碳排放,虽然生命周期成本会略有增加,但其减碳效果,大于单纯依靠围护结构性能提升的传统做法;尽可能利用建筑空间配置光伏对减少碳排放及生命周期成本都是有利的;通过软件联合模拟可实现建筑围护结构和光储系统的协同优化,且较于各自独立优化,能取得更好的设计方案.

基于改进PSO的多目标新能源微电网HESS模型

针对目前我国电网混合储能控制系统存在运行成本高、控制效果低的问题。提出了一种基于多目标的新能源微电网混合储能控制系统(HESS)模型,以降低可再生能源电力波动和最低运行成本为目标函数建立优化方程。提出了一种改进粒子群算法(PSO)获得多目标函数权重参数,从而计算最优存储系统控制信号。实验结果表明,与传统储能控制模型相比,所提基于多目标的新能源微电网混合储能控制模型的优化混合储能容量在整个运行周期内可节省4.3%的运行成本。所提模型在抑制总线功率波动方面更为出色,可有效延长电池的使用寿命。

A Model Predictive Control Method for Hybrid Energy Storage Systems

The traditional PI controller for a hybrid energy storage system(HESS)has certain drawbacks,such as difficult tuning of the controller parameters and the additional filters to allocate high-and low-frequency power fluctuations.This paper proposes a model predictive control(MPC)method to control three-level bidirectional DC/DC converters for grid-connections to a HESS in a DC microgrid.First,the mathematical model of a HESS consisting of a battery and ultra capacitor(UC)is established and the neutral point voltage imbalance of a three-level converter is solved by analyzing the operating modes of the converter.Secondly,for the control of the grid-connected converters,an MPC method is proposed for calculating steady-state reference values in the outer layer and the dynamic rolling optimization in the inner layer.The outer layer ensures the voltage regulation and establishes the current predictive model,while the inner layer,using the model predictive current control,makes the current follow the predictive value,thus reducing the system current ripple.This cascaded topology has two independent controllers and is free of filters to realize the high-and low-frequency power allocation for a HESS.Therefore,it allows two types of energy storage devices to independently regulate the voltage and realizes the power allocation of the battery and UC.Finally,simulation studies are conducted in PSCAD/EMTDC,and the effectiveness of the proposed HESS control strategy is verified in a case,such as a controller comparison and fault scenario.

Supercharging of Diesel Engine with Compressed Air: Experimental Investigation on Greenhouse Gases and Performance for a Hybrid Wind-Diesel System

Supercharging is the process of supplying air for combustion at a pressure greater than that achieved by natural or atmospheric induction, as applied to internal combustion engines. As a consequence of demonstrated technological, economical and energetic advantages in multiple literature evaluations concerning the large scale wind-compressed air hybrid storage system with gas turbines, the utilization of a hybrid wind-diesel system with compressed air storage (HWDCAS) has been frequently explored. These will mainly have average or small scale application such as the powering of isolated sites. It has been proven in numerous studies that the HWDCAS combined with an additional supercharging of the diesel engines will contribute to the increase of the power and efficiency of the diesel engine, the reduction of both fuel consumption and the emission of greenhouse gases (GHG). This article presents the obtained results from experimental validation of the selected design with an aim to valorize this innovative solution and become trustworthy.

Modelling and Optimal Design of Hybrid Power System Photovoltaic/Solid Oxide Fuel Cell for a Mediterranean City

This work presents a hybrid power system consisting of photovoltaic and solid oxide fuel cell(PV-SOFC)for electricity production and hydrogen production.The simulation of this hybrid system is adjusted for Bou-Zedjar city in north Algeria.Homer software was used for this simulation to calculate the power output and the total net present cost.The method used depends on the annual average monthly values of clearness index and radiation for which the energy contributions are determined for each component of PV/SOFC hybrid system.The economic study is more important criterion in the proposed hybrid system,and the results show that the cost is very suitable for the use of this hybrid system,which ensures that the area is fed continuously with the sufficient energy for the load which assumed to be 500 kW in the peak season.The optimized results of the present study show that the photovoltaic is capable of generating 8733 kW electricity while the SOFC produces 500 kW electricity.The electrolyzer is capable of producing 238750 kg of hydrogen which is used as fuel in the SOFC to compensate the energy lack in nights and during peak season.

Hybrid Power System Options for Off-Grid Rural Electrification in Northern Kenya

For domestic consumers in the rural areas of northern Kenya, as in other developing countries, the typical source of electrical supply is diesel generators. However, diesel generators are associated with both CO2 emissions, which adversely affect the environment and increase diesel fuel prices, which inflate the prices of consumer goods. The Kenya government has taken steps towards addressing this issue by proposing The Hybrid Mini-Grid Project, which involves the installation of 3 MW of wind and solar energy systems in facilities with existing diesel generators. However, this project has not yet been implemented. As a contribution to this effort, this study proposes, simulates and analyzes five different configurations of hybrid energy systems incorporating wind energy, solar energy and battery storage to replace the stand-alone diesel power systems servicing six remote villages in northern Kenya. If implemented, the systems proposed here would reduce Kenya’s dependency on diesel fuel, leading to reductions in its carbon footprint. This analysis confirms the feasibility of these hybrid systems with many configurations being profitable. A Multi-Attribute Trade-Off Analysis is employed to determine the best hybrid system configuration option that would reduce diesel fuel consumption and jointly minimize CO2 emissions and net present cost. This analysis determined that a wind-diesel-battery configuration consisting of two 500 kW turbines, 1200 kW diesel capacity and 95,040 Ah battery capacity is the best option to replace a 3200 kW stand-alone diesel system providing electricity to a village with a peak demand of 839 kW. It has the potential to reduce diesel fuel consumption and CO2 emissions by up to 98.8%.

考虑储能SOC自恢复的风电波动平抑混合储能容量配置策略

针对混合储能系统(HESS)平抑风电功率波动过程中HESS有功功率参考误差大、储能荷电状态(SOC)控制困难造成储能配置成本过高的问题,提出考虑SOC自恢复的混合储能系统容量优化配置策略。首先,考虑单一风电平抑滤波算法平滑性与跟踪性不能兼顾的问题,提出限幅与滑动平均加权滤波算法,动态调整算法权重和限幅参数,降低并网功率滞后时间,提升HESS有功功率参考准确性;然后,引入HESS累积放电量为分解对象,研究基于频率划分的HESS有功功率分配方法,避免功率参考二次修正、实现储能SOC自恢复控制;最后,以储能配置成本最低为目标,建立HESS全生命周期优化配置模型。基于风电场实测数据设计仿真验证方案,结果表明,该文策略可提高储能风电波动补偿裕度,降低储能配置成本。

运行工况自适应的风储系统双层功率平滑策略

针对风电并网带来的功率波动问题,提出一种运行工况自适应的风电-混合储能系统双层功率平滑策略。在上层,考虑风储系统并网功率波动和储能运行状态,利用无模型自适应控制动态跟踪经滑动平均算法得到的并网参考功率,生成混合储能总功率任务;在下层,考虑储能介质的技术特性,利用模糊控制动态调节经变分模态分解确定的混合储能总功率任务的频率分界点,完成功率的自适应分配。算例分析表明:所提策略可以自适应平抑多工况下的风电功率波动,实现混合储能各介质间功率的合理分配。

基于Stacking融合模型的PHEV复合储能系统实时能量分配策略

为了解决插电式混合动力汽车单一电池低比功率、无法响应暂态功率需求的问题,设计了电池和超级电容并联式复合储能系统。同时针对采用动态规划法优化负载电流分配时缺乏实时性的问题,利用不同驱动工况下动态规划优化的结果构成训练集进行训练,并综合GRU网络以及XGBoost算法,提出了一种Stacking集成学习框架下多模型融合的能量分配策略。仿真结果表明,与仅使用单一电池的储能系统相比,基于Stacking融合模型的实时能量分配系统在UDDS和US06两种循环工况下,电池峰值电流分别降低了48.7%和50.8%,有效削弱了电池的峰值电流,提升了电池的整体性能。

基于优化赋权模型预测控制的风储协调策略研究

风储系统多目标之间存在难以协调控制的问题,权重系数的选择对多目标控制效果具有显著影响。首先,构建以储能充放平衡、并网波动最小和储能输出最小的风储系统多目标函数,考虑各子目标权重系数对风储系统的影响,提出一种改进鲸鱼算法(IWOA)优化模型预测控制(MPC)的风储协调运行方法,采用组合隶属度函数进行满意度评价,得到混合储能最优总控制量和权重系数。然后,采用集合经验模式分解(ICEEMDAN)算法对混合储能总控制量进行分解,利用Pearson相关系数对分解分量进行重构,实现混合储能功率的分配。最后,以新疆某风电场数据进行仿真,验证所提优化模型的有效性和功率分配策略的合理性。

混合储能聚合商参与能量-调频市场控制策略

提出了一种混合储能聚合商(hybrid energy storage aggregator,HESA)参与能量-调频市场的控制策略。首先,对于独立系统运营商(ISO)发出的调频指令信号进行VMDWVD时频域分析,重构固有模态分量(IMF)生成高频信号与低频信号,分别作为HESA中功率型储能和能量型储能的输入信号。其次,构建了计及多市场价格不确定性的HESA投标与运行策略min-max-min模型,基于列和约束生成算法(C&CG)和强对偶理论对主子问题进行迭代交替求解。最后,基于实际PJM市场的价格、调频信号等数据进行了仿真,验证了HESA主体投标运营策略的有效性。

基于混合储能的风光储联合发电系统优化调度策略及评价

针对用户用电需求和可再生能源发电情况,建立以系统总运行成本最小为优化目标的并网型风-光-蓄电池-废弃矿井抽蓄联合发电系统优化调度模型,以等效负荷方差、联络线波动率、供电损失率为评价指标衡量优化调度结果,利用CPLEX求解器对调度模型进行最优求解。对3种不同储能形式的优化调度模型进行仿真对比,结果显示:储能形式为蓄电池和废弃矿井抽蓄的混合储能时的总成本相比蓄电池与废弃矿井抽蓄分别减少了62.21%与49.18%;利用组合熵权秩和比法对优化结果进行排序评价,风-光-蓄电池-废弃矿井抽蓄联合发电系统加权秩和比值为0.833,评分排序最优。所提模型在提升系统运行经济性的同时,提高了系统供电的可靠性,验证了所提模型的合理性与有效性。