分布式发电中燃料电池的建模与控制

合适的燃料电池(fuel cell,FC)动态模型对分布式发电技术的研究起着很重要的作用。提出了非线性质子交换膜燃料电池和固体氧化物燃料电池的动态模型,该模型考虑了燃料利用率的影响和各种反应物随时间变化的压力。并在该模型的基础上,应用电池效率和发电经济性分析得出了燃料利用率一般控制在0.7~0.9范围内比较好。详细阐述了FC在并网运行时的控制策略,以及在含FC发电系统的潮流计算中,将FC的并网节点当作PV节点来处理。     

Frequency control of a wind-diesel system based on hybrid energy storage

Owing to the significant number of hybrid generation systems (HGSs) containing various energy sources, coordination between these sources plays a vital role in preserving frequency stability. In this paper, an adaptive coordination control strategy for renewable energy sources (RESs), an aqua electrolyzer (AE) for hydrogen production, and a fuel cell (FC)-based energy storage system (ESS) is proposed to enhance the frequency stability of an HGS. In the proposed system, the excess energy from RESs is used to power electrolysis via an AE for hydrogen energy storage in FCs. The proposed method is based on a proportional-integral (PI) controller, which is optimally designed using a grey wolf optimization (GWO) algorithm to estimate the surplus energy from RESs (i.e., a proportion of total power generation of RESs: Kn). The studied HGS contains various types of generation systems including a diesel generator, wind turbines, photovoltaic (PV) systems, AE with FCs, and ESSs (e.g., battery and flywheel). The proposed method varies Kn with varying frequency deviation values to obtain the best benefits from RESs, while damping the frequency fluctuations. The proposed method is validated by considering different loading conditions and comparing with other existing studies that consider Kn as a constant value. The simulation results demonstrate that the proposed method, which changes Kn value and subsequently stores the power extracted from the RESs in hydrogen energy storage according to frequency deviation changes, performs better than those that use constant Kn. The statistical analysis for frequency deviation of HGS with the proposed method has the best values and achieves large improvements for minimum, maximum, difference between maximum and minimum, mean, and standard deviation compared to the existing method.     

Evaluation of Residential PV‐EV System for Supply and Demand Balance of Power System

In recent years, there has been a growing interest in ecofriendly technologies such as residential photovoltaic (PV) systems and electric vehicles (EVs). PV systems and EVs will contribute to reducing CO₂ emissions in the residential sector and the transportation sector, respectively. In spite of that, high penetration of PV systems into the power grid can cause grid voltage and frequency stability problems. Also, the growth of the EV market will create an extra electricity load (for charging the EV fleet), leading to an increase in power utility fuel costs. In this research, we proposed the usage of the PV‐EV system as a method of mitigating the impact the spread of residential PV systems and EV on the power grid. We built an PV‐EV system simulation model and investigated the PV‐EV system contribution to the balance of power supply and demand and to reducing the total cost of the household under different electricity pricing scenarios. We also evaluated the effect of uncertainty in the forecasting of load and PV output on the performance of the PV‐EV system.     

A study on collaborative operation method for a new energy type dispersed power supply system by AC‐EMAP model

Application of a dispersed power supply system consisting of a large‐scale photovoltaic system (PV), a fuel cell (FC), and an electric double layer capacitor (EDLC) is studied in this paper. This system is operated in autonomous mode, taking account of time delay characteristics of FC. The modified Euler type Moving Average Prediction (EMAP) model is improved using short‐time fast Fourier transform (ST‐FFT). The Adaptive Control type EMAP (AC‐EMAP) model is introduced to reduce the capacity of EDLC. This system can meet the multi‐quality electric power requirements of customers, and improve voltage stability and uninterruptible power supply (UPS) function as well. Moreover, the required capacity of EDLC to compensate the fluctuation of both PV output and Load demand is clarified by a simulation based on collaborative operation method by a prediction model using software MATLAB/Simulink. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(1): 13–24, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20262     

Adaptive coordination control strategy of renewable energy sources, hydrogen production unit, and fuel cell for frequency regulation of a hybrid distributed power system

The ‘mismatch losses’ problem is commonly encountered in distributed photovoltaic (PV) power generation systems. It can directly reduce power generation. Hence, PV array reconfiguration techniques have become highly popular to minimize the mismatch losses. In this paper, a dynamical array reconfiguration method for Total-Cross-Ties (TCT) and Series–Parallel (SP) interconnected PV arrays is proposed. The method aims to improve the maximum power output generation of a distributed PV array in different mismatch conditions through a set of inverters and a switching matrix that is controlled by a dynamic and scalable reconfiguration optimization algorithm. The structures of the switching matrix for both TCT-based and SP-based PV arrays are designed to enable flexible alteration of the electrical connections between PV strings and inverters. Also, the proposed reconfiguration solution is scalable, because the size of the switching matrix deployed in the proposed solution is only determined by the numbers of the PV strings and the inverters, and is not related to the number of PV modules in a string. The performance of the proposed method is assessed for PV arrays with both TCT and SP interconnections in different mismatch conditions, including different partial shading and random PV module failure. The average optimization time for TCT and SP interconnected PV arrays is 0.02 and 3 s, respectively. The effectiveness of the proposed dynamical reconfiguration is confirmed, with the average maximum power generation improved by 8.56% for the TCT-based PV array and 6.43% for the SP-based PV array compared to a fixed topology scheme.     

基于电—氢混合储能的风氢耦合系统建模与控制

为改善高比例联网风电的反调峰、不可控等冲击电网的不利特性,提出了一种基于电—氢混合储能的风氢耦合系统控制策略。建立直驱永磁风电机组、电解槽、燃料电池及超级电容器数学模型,研究耦合在直流母线的电解槽、燃料电池、超级电容器与直驱永磁风电机组之间的量化关系,设计风氢耦合系统的上层控制策略,并进行分析与研究。PSCAD/EMTDC中的仿真结果表明:通过超级电容器、电解槽与燃料电池的协调配合,超级电容器完全可以弥补电解槽与燃料电池响应延迟功率,同时实现风氢耦合系统出力可控、功率外特性友好,有效验证了本文所建立各设备数学模型的准确性及设计控制策略的有效性。     

Characteristics of photovoltaic/fuel cell power hybrid system. (Effect on electrical load form factors)

The photovoltaic power system has a great future as a clean-energy alternative to fossil fuel which has many environmental problems such as gas exhaustion or air pollution. Sunlight, a source of energy for the system, is influenced greatly by weather conditions, seasons and times of day. Therefore it cannot supply constant electric power. The photovoltaic/fuel cell power hybrid system is assumed. It combines PV array, hydrogen generator, storage tank and fuel cells by using hydrogen. This system can supply constant electric power to the electric load in a solitary island separated from a commercial electric network. The possibility of this system is examined by computer simulation. Input data include the global irradiance on inclined plane and temperature of HASP data of Tokyo, ten kinds of electrical load forms with 400 MWh electric power a year, and conversion efficiencies of each subsystem. As a result of simulation, it was revealed that the area of PV array with 8170 m² and the volume of hydrogen tank from 22 × 10³ to 30 × 10³ kl are necessary.     

An operating method using prediction of photovoltaic power for a photovoltaic–diesel hybrid power generation system

This paper describes a novel operating method using prediction of photovoltaic (PV) power for a photovoltaic–diesel hybrid power generation system. The system is composed of a PV array, a storage battery, a bidirectional inverter, and a diesel engine generator (DG). The proposed method enables the system to save fuel consumption by using PV energy effectively, reducing charge and discharge energy of the storage battery, and avoiding low‐load operation of the DG. The PV power is simply predicted from a theoretical equation of solar radiation and the observed PV energy for a constant time before the prediction. The fuel consumption of the proposed method is compared with that of other methods by a simulation based on measurement data of the PV power at an actual PV generation system for 1 year. The simulation results indicate that the amount of fuel consumption of the proposed method is smaller than that of any other methods, and is close to that of the ideal operation of the DG. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(3): 8–18, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20116     

风光氢联合式独立发电系统的建模及仿真

提出了一种独立使用的风光氢联合式独立发电系统，该系统由风力发电、太阳能发电、氢能系统(包括电解水制氢、燃料电池系统、超级电容等)及其他系统单元组成。各单元通过2条直流总线联接，并采用功率流控制。由于风力发电与太阳能发电所输出的功率随风速和日照的变化而变化，因此采用燃料电池系统与超级电容堆与风光发电系统配合使用，以保证系统在任何条件下都具有可靠的供电性能。当风能与太阳能充足时，风机与光伏阵列可满足负荷的需要，同时还可向电解池供电；如果不能满足负荷的需要则由燃料电池提供额外的电能，同时由超级电容在短时期内向负荷提供燃料电池最大功率以外的那部分电能。最后在Matlab环境下建立了系统仿真模型，并以西藏边远村落为例对该系统的动态响应进行了仿真分析，仿真结果表明本文提出的供电系统可以用于以西藏为典型代表的风速和光能变化较大的边远地区。     

Energy management optimization of a hybrid power production unit based renewable energies

Hybrid power production units seem to be an interesting alternative for supplying isolated sites. This study proposes a new supervision strategy in order to ensure an optimized energy management of the hybrid system. The considered hybrid unit includes a wind generator (WG), a fuel cell (FC), an electrolyzer (EL) and a supercapacitor (SC). An overall power supervision approach was designed to guarantee the power flow management between the energy sources and the storage elements. The aim of the control system is to provide a permanent supply to the isolated site by adapting production to consumption according to the storage level. A mathematical analysis of the hybrid system using models implemented in Matlab/Simulink software was developed. Simulation results illustrate the performance of the control strategy for an optimal management of the hybrid power production unit under different scenarios of power generation and load demand.     

A Hydrogen‐Storage Distributed Generation System Using Unitized Reversible Cells and Its Operational Scheme

Environmental issues such as global warming and depletion of natural energy resources are posing problems. Photovoltaic systems have been attracting attention as a form of renewable energy. The output power of a photovoltaic system changes sharply because solar radiation intensity and temperature vary with the weather. In conventional photovoltaic systems, the surplus power, excluding the power consumed in the load, flows back to the grid. Therefore, fluctuations in the output power of a photovoltaic system may have an adverse effect on the grid. This paper proposes a novel hydrogen‐storage distributed generation system using a unitized reversible cell that integrates a fuel cell and water electrolyzer to smooth reverse power flow. The hydrogen‐storage distributed generation system was modeled and a computer simulation was performed. Using two evaluation methods, the proposed system is shown to be effective at leveling power flow back to the grid.     

基于模型预测控制的新型电力系统光储电站调频控制策略

光伏渗透率的不断提高降低了新型电力系统的转动惯量,给系统频率稳定性带来了新的挑战,储能出力灵活且迅速,将储能与光伏结合构成光储电站参与电网调频能够提高新型电力系统频率稳定性。光储电站参与系统调频的有功出力受到光照强度、储能荷电系数等多因素的影响,然而现有的与光储电站调频控制有关的研究大多对这些多约束的处理能力较差。在此背景下,提出一种基于模型预测控制的新型电力系统光储电站调频控制策略。该控制策略以最小化系统频率偏差与频率变化率之和为目标,计及光储电站有功出力及总发电量约束,优化光储电站有功出力,并通过控制光储电站有功输出参与系统频率调节。最后,通过仿真算例说明了所提方法相比传统控制策略调频效果更优,能够在考虑多约束的情况下快速精准确定光储电站出力,提高系统频率稳定性。     

基于模型预测控制的新型电力系统光储电站调频控制策略

光伏渗透率的不断提高降低了新型电力系统的转动惯量,给系统频率稳定性带来了新的挑战,储能出力灵活且迅速,将储能与光伏结合构成光储电站参与电网调频能够提高新型电力系统频率稳定性。光储电站参与系统调频的有功出力受到光照强度、储能荷电系数等多因素的影响,然而现有的与光储电站调频控制有关的研究大多对这些多约束的处理能力较差。在此背景下,提出一种基于模型预测控制的新型电力系统光储电站调频控制策略。该控制策略以最小化系统频率偏差与频率变化率之和为目标,计及光储电站有功出力及总发电量约束,优化光储电站有功出力,并通过控制光储电站有功输出参与系统频率调节。最后,通过仿真算例说明了所提方法相比传统控制策略调频效果更优,能够在考虑多约束的情况下快速精准确定光储电站出力,提高系统频率稳定性。     

Online energy management strategy of a hybrid fuel cell/battery/ultracapacitor vehicular power system

A hybrid power system based on a fuel cell (FC) and an energy storage system appears to be very promising for satisfying the high energy and high power requirements of automotive applications in which the power demand is impulsive rather than constant. This paper deals with the use of a hybrid energy storage system with the battery (BAT)/ultracapacitor (UC) as ancillary power source in FC electric vehicles. The energy management strategy (EMS) is one of the most important issues for the efficiency and performance of such systems. The designed EMS uses a splitting method, allowing a natural frequency decomposition of the power demands. It takes into account the slow dynamics of FC and the state of charge of the UC and BAT. A simulation is conducted using MATLAB/SIMULINK software in order to verify the effectiveness of the proposed control strategy. It confirms the performance of the control method and also demonstrates the robustness and stability of the control strategy with good tracking response (transient performance), low overshoot, zero steady‐state error, and control flexibility during a power demand cycle. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

光伏组件潜在诱导衰减效应的研究

光伏组件的潜在诱导衰减会减少光伏发电系统对外输出的电能,严重情况下使光伏发电系统瘫痪,几乎不对外输出电能。在温度为85℃和85%湿度条件下,对单块光伏组件模拟光伏发电系统中出现的潜在诱导衰减效应,即组件的铝边框和输出端产生1 000 V的电势差。每隔6 h测试一次组件的电致发光(EL)图像和I-V电性能,实验持续时间为48 h。结果表明:该效应会使组件产生漏电,漏电程度随着实验持续的时间而变得严重。运用电容原理解释潜在诱导衰减产生的物理机制,并采用低介电常数的封装材料制作新的光伏组件,能使组件的功率衰减控制在2%以内,完全具有抗潜在诱导衰减的性能。     

基于分层控制的光—储—燃直流供电系统能量管理方法

为克服光伏发电的随机性和间歇性,实现高可靠性、高品质供电,提出一种基于光伏/蓄电池/超级电容/燃料电池的直流供电系统能量管理分层控制方法。针对混合直流供电系统的多参数、非线性特性,上层控制设计微分平滑方法直接补偿非线性分量,实现系统非线性动态可逆,确保在光伏出力大幅变化、负载突变或系统参数发生摄动情形下,使系统直流母线电压依然能够稳定运行,同时为下层控制提供总载荷电流参考轨迹;针对混合直流供电系统中多电源的不同特性,下层控制采用模型预测方法,以延长系统循环使用寿命为目标,设计加权因子,根据光伏出力和负载功率需求状况,动态调节储能单元充放电速率,使系统快速跟踪总载荷电流期望轨迹,实现各电源间功率的合理分配。基于MATLAB/Simulink的仿真结果验证了所提能量管理分层控制方法的可行性和有效性,该方法具有结构简单、动态响应快、鲁棒性高、稳定性好的特点。     

不间断电力变电站中分布式电源接入系统研究

将新兴的发电技术(风力发电、燃料电池发电)及新型储能技术(制氢储能、超导储能装置)引入传统的电力变电站后,由于各分布式电源的多样性和复杂性,使得整个系统的运行和控制变的复杂,独立运行单个分布式电源,很难维持整个系统的频率和电压稳定。提出让高度可控的分布式电源,如燃料电池发电系统在通过电压源型逆变器并网的同时参与系统的频率和电压调节,用以解决随机性较大的分布式电源,如风力发电系统功率输出的随机性导致电网电能质量下降的问题。最后通过仿真分析验证了储能装置的这种并网方式能够有效地提高变电站输出电能质量。     

High-Power Electric Ship Propulsion Systems with Advanced Frequency Converters

Russian Electrical Engineering - Three types of frequency converter (FC) structures are considered as parts of high-power electric ship propulsion systems—multilevel FCs, cascade FCs, and FCs...     

基于CEEMDAN-HT的平抑光伏出力混合储能 容量优化配置

光伏出力具有间歇性和波动性,利用储能装置可减小光伏并网对电网的影响。以平抑光伏功率波动效果为标准,提出了一种由超级电容和蓄电池组成的混合储能系统(hybrid energy storage system, HESS)的容量配置方法。采用由递推平均和中值平均加权滤波的算法平滑光伏出力,得到光伏并网功率和HESS参考功率。利用完全集合经验模态分解和希尔伯特变换提取HESS 参考功率的高频与低频分量,对HESS内部功率进行一次分配。之后为了避免HESS荷电状态频繁越限,同时保证HESS能持续工作,提出一种HESS功率的均衡管理方法,对一次分配功率的衰减进行修正,再对修正后的HESS参考功率进行容量配置。最后,基于全寿命周期成本建立经济评估模型,对比不同的储能容量配置策略,利用实际数据仿真验证了所提方法的有效性与经济性。     

计及光伏出力不确定性的氢能综合能源系统经济运行策略

针对分布式光伏出力的不确定性特征对系统运行经济性的影响,提出了一种计及光伏出力不确定性的氢能综合能源系统经济运行策略.首先,搭建氢燃料电池的热电输出控制模型和氢能综合能源系统的热力系统模型;然后,在光伏出力预测数据的基础上,通过分析光照强度变化的不确定性以修正光伏出力预测曲线;最后,以最小化系统日运行成本为目标函数,建立包含光伏、氢燃料电池、热电联产机组的氢能综合能源系统的运行优化模型.算例分析结果表明,考虑光伏出力不确定性对氢燃料电池输出的影响,可使系统设备的出力更加合理,对降低运行成本、提高氢能综合能源系统的运行可靠性具有积极作用.