飞轮与电池混合储能的直流微网母线电压波动抑制策略

针对直流微网母线电压波动的关键技术问题,研究基于飞轮储能、磷酸铁锂电池混合储能的数学模型,考虑储能的功率密度、能量密度以及负荷突变等复杂情形,围绕电压波动机理与荷电状态约束设计了改进下垂控制策略,分别从单元级和系统级两方面开展母线电压平抑工作,为母线电压稳定问题的解决提供了基本思路。最后,采用大型数字化仿真软件PSCAD/EMTDC和实验室平台进行了实验测试,结果表明设计方案合理、可行,能够快速跟踪母线电压并有较好的抑制效果。     

电气化轨道交通牵引网电储能系统优化研究

将丙烯酰胺水凝胶材料应用于超级电容器，可以在电气化轨道交通中存储再生制动能量提升牵引网电压水平。在分析电气化轨道交通运行状态的基础上，提出一种遵循储能系统能量改善方法来调节牵引网充放电阈值电压。建立了包括列车、储能系统、牵引变电站在内的直流牵引电力系统的数学模型。在不同条件下，通过对牵引网电压和列车状态的实时监测，确定能量管理状态机，并利用实际线路数据进行仿真和主铁路轨道场实验，验证了所提管理策略的合理性和有效性。研究结果分析可知，能源管理状态机可以在非常理想的状态下运行，平均节能率高达21.7%,反映了所提出的能源管理策略的有效性和稳定性。     

飞轮储能对永磁直驱风电机组并网有功功率的平滑控制策略研究

针对风速随机性引起的机组并网有功功率波动问题,提出在采用最大风能捕获策略的永磁直驱风电机组交-直-交变流器的直流侧接入飞轮储能系统,利用飞轮系统的能量缓存作用,以实现永磁直驱风电机组的输出有功功率平滑控制。设计了飞轮储能系统的能量控制策略,并对采用了飞轮储能系统的永磁直驱风电机组的运行特性进行了仿真研究,经仿真验证:采用所提出的飞轮储能系统能量控制策略能够有效平滑风电机组输出有功功率,提高了风电机组的输出电能质量。     

飞轮储能在风电系统中的应用及仿真分析

在飞轮储能系统基本结构和工作原理的基础上,对其在独立运行和并网型风力发电系统中的应用进行了阐述,并以Matlab为平台搭建了飞轮储能系统的仿真模型。由于充电模型和放电模型仅转子运动方程部分不同,所以仅建立了充电模型,其中包括电机模块、位置检测模块、系统控制器模块和输出电压模块。最后,基于所建立的仿真模型,对充、放电完整过程进行了仿真,并分析了改变转动惯量、摩擦系数和磁极对数对系统转速性能所造成的影响。由于仿真结果和理论分析一致,证实了所建立的飞轮储能系统的正确性。     

变速恒频风电系统优化控制策略研究

通过分析网侧变换器和定子侧变换器运行原理,提出变换器的数学模型和控制策略,利用定子磁链定向矢量控制方法和电网电压定向的矢量控制方法,建立矢量控制方程式,采用双闭环控制策略实现定子有功功率、无功功率的解耦控制,使得网侧保持功率因数运行和直流母线电压稳定。通过MAT-LAB／sIMuLINK软件,构建了风电系统仿真模型,仿真结果验证了矢量控制的可行性。     

固定式电解水制氢-储氢-加氢系统安全防护

氢能具有可循环、可储存、零排放等特点,是全球能源低碳转型发展的重要载体,对实现碳中和目标具有重要意义。氢的体积能量密度低、运输成本高,采用制氢-储氢-加氢一体化的新思路可以节省氢气的运输成本从而提升经济效益,但系统复杂、相关安全防护尚不健全,可能导致系统运行故障,影响多能互补系统的安全与稳定。本文基于浙江某氢电耦合直流微网示范项目,分析了固定式电解水制氢-储氢-加氢一体化系统的潜在风险,提出了本质安全设计、过程监测与控制、报警、安全仪表功能及自动联锁、应急响应体系、完善标准规范六个方面的安全防护措施,为氢电耦合直流微网系统的优化设计及安全运行提供参考,最后结合质子交换膜电解水制氢技术的优势,展望了固定式电解水制氢-储氢-加氢一体化系统的发展前景。     

双闭环直流调速系统仿真研究

本文介绍了双闭环直流调速系统的原理,通过试验的方法获得双闭环直流调速系统的各项参数。设计了电流和转速调节器,在MATLAB中建立仿真模型,最后采用MATLAB/Simulink中的Power System工具箱对所设计的系统进行仿真,得到了比较理想的运行曲线。     

SMES超导磁体动态载荷温度场仿真分析

研究了超导磁储能磁体在动态载荷作用下的热稳定性,基于有限元方法构建了直接冷却高温超导磁储能磁体的数学模型,进行了充放电过程磁体温度场仿真,研究表明,在间断载荷作用下磁体具有较好的热稳定性,在连续载荷作用下,控制励磁电流速度和间隔时间可保证磁体的运行温度在30 K以下。     

新能源接入下微电网混合储能参数变量优化配置研究

针对新能源接入下微电网储能系统的负荷功率大、储能装置分配不合理、运行成本高的问题,研究新能源接入下微电网混合储能容量优化配置方法。设置新型微电网混合储能容量守恒条件,选择自适应粒子群算法参数变量并优化,建立微电网混合储能容量系统目标函数,获取储能优化约束条件,实现微电网混合储能容量的优化配置。实验结果表明,所提出的方法可以降低优化配置运行成本,提高备用和微电网混合储能容量优化配置效果。     

基于改进LSSVM的一元受电弓弓网接触力建模仿真

本文提出基于最小二乘支持向量机(LSSVM)的弓网系统的建模方法,并对弓网广义模型进行辨识及仿真研究.首先根据一元受电弓等效模型给出弓网系统的离散化模型,并进一步构建弓网系统的广义模型,然后根据改进的LSSVM的方法对模型参数进行辨识,利用Matlab的Simulink模块搭建弓网系统动力学模型并进行仿真试验.结果表明...     

TDLAS检测系统的激光器驱动电路

针对温度变化对半导体激光器(LD)的输出激光波长及其工作稳定性的影响,提出运用热电制冷器TEC构成二级制冷系统,分别对激光器的外部和内部温度进行精准控制。采用闭环PID电路产生控制信号控制TEC的驱动电流和方向,从而达到制冷和加热的目的;为进一步实现对驱动信号的滤波,提出采用级联方式的LTC1064构成四阶滤波系统。测试结果表明:TEC温控系统取得了很好的温控效果,响应速度快,精度达到±0.01℃,滤波系统有效滤除了正弦波中的直流分量和高次谐波的干扰,满足激光器对温度和驱动信号的要求。     

多进料脱甲烷塔进料位置切换的控制策略

进料位置和控制器的操作参数是显著影响精馏塔单元分离和节能效率的重要参数。为此提出一种动态多进料切换和控制器参数切换控制策略。在脱甲烷塔系统动态模拟和控制的基础上,对脱甲烷塔多进料位置切换的控制方案进行验证,并分别实现对进料位置和控制器参数的分步和同步切换。结果表明:同步切换方法更有利于实现多进料位置和控制器参数的切换。     

基于定型结构相变储热模块小区供热的智慧控制系统

研究了基于定型结构相变储热模块小区供热的智慧控制系统,对定型结构相变储热模块及供热系统进行了描述。结合冬季供热的负荷系数随室外环境温度的变化规律,提出小区供热的智慧控制系统及其内涵。结合城市小区供热的示范工程,智慧供热系统与传统二种操作模式进行对比,分别降低供热设备运行费用24%、32%。基于定型结构相变储热模块供热系统,因为使用低谷电或可再生能源用电,使用智慧控制系统后,运行费用降低明显。智慧供热系统与传统两种操作模式进行对比,分别降低供热设备运行费用70%、73.3%。因此,基于定型结构相变储热模块小区供热,采用智慧供热系统对于运行费用降低具有非常重要的意义。     

基于PLC的永磁无刷直流电机调速控制

针对永磁无刷直流电机运行过程中存在的转矩波动干扰问题,提出了一种基于PLC的电机转矩波动抑制的自抗扰控制方法,将被控对象简化为两个非线性串联环节,分别设计了各自的自抗扰控制器来实现永磁无刷直流电机的内环转矩控制与外环转速控制.     

Optimal operation of the boil-off gas compression process using a boil-off rate model for LNG storage tanks

Proper handling of boil-off gas (BOG) significantly affects the operational efficiency as well as the safety of the whole LNG gasification plant. Due to the not well-known inherent dynamics, it has been suspected that the BOG compressors are being operated at too much capacity, unnecessarily consuming too much energy. An empirical model is proposed for the estimation of the boil-off rate (BOR) in an LNG storage tank, based on the specification supplied by the LNG storage tank manufacturer. By using the BOR model, an optimal operation algorithm is proposed for a safe and energy-saving BOG compressor operation, which minimizes the power consumption while preparing against the potential failure of one of the operating compressors. Case study results indicate that the energy consumption could be reduced by a half of the conventional method, by increasing the tank pressure while the safety is maintained. The proposed method is expected to be able to contribute to improving the efficiency of the whole gasification plant operation and control without tempering the safety requirements.     

Modeling a Reversible Solid Oxide Fuel Cell as a Storage Device Within AC Power Networks

A reversible solid oxide fuel cell (RSOFC) system, consisting of a RSOFC stack, heat store, and electrical inverters to convert DC to AC power, is shown by computer modeling to have the potential to efficiently store electrical energy. This paper describes the modeling of a single RSOFC, based on a proposed cell geometry, empirical data on the resistivities of the components, and calculation of activation and diffusion polarization resistances from electrochemical theory. Data from ac impedance spectroscopy measurements on symmetrical cells are used to model RSOFC impedance. A RSOFC stack is modeled by electrically linking the individual cells inside a pressurized vessel. A phase change heat store is added to improve energy storage efficiency. The model is implemented in MATLAB®/Simulink®. Two competing inverter control schemes are compared, trading off DC bus ripple against AC power quality. It is found that selection of appropriate DC bus capacitance is important in certain scenarios, with potential system cost implications. It is shown that the system can store electrical energy at an efficiency of 64% over a single discharge–charge cycle, i.e., hydrogen to electricity and heat to hydrogen.     

A Ferroconcrete‐Like All‐Organic Nanocomposite Exhibiting Improved Mechanical Property,High Breakdown Strength,and High Energy Efficiency

Polymer‐based nanocomposite dielectrics with high energy storage capacity are crucial enablers for numerous applications in modern electronic and electrical industries. The energy density of parallel plate capacitors is determined by breakdown strength and dielectric permittivity of the inner dielectrics. Poly(vinylidene fluoride‐trifluoroethylene‐chlorofluoroethylene) (P(VDF‐TrFE‐CFE)), with the highest permittivity among all the dielectric polymers, is a promising candidate for high energy density capacitors. However, its relatively low breakdown strength and energy efficiency restrict the applications. In this work, a new method combining combinatorial‐electrospinning and hot‐pressing is proposed to fabricate P(VDF‐TrFE‐CFE)‐based all‐organic dielectrics with ferroconcrete‐like structure. In this structure, continuous fibers of polysulfone (PSF) with high Young's modulus act as tough scaffold to improve the mechanical properties of nanocomposites, and an over 750% enhancement of Young's modulus is obtained. The enhanced mechanical properties bring about significant improvement in Weibull breakdown strength to 485 MV m^?1, more than 50% higher than neat terpolymer. Furthermore, the suppressed leakage current and conduction loss, and hence the improved discharge energy efficiency under moderate electric field, are achieved due to the high insulation of PSF and its interfacial restriction on space charge mobility.     

AC/DC电源线自动绕扎系统的设计与实现

针对原AC/DC电源线绕扎设备存在的问题,设计了一个AC/DC电源线自动绕扎系统。介绍系统的工艺流程与结构组成,给出系统的硬件电路设计和软件程序流程。该系统在实际生产环节中可代替4~5人的人工操作岗位,使AC/DC电源线的生产效率提高5~7倍。     

Operating behaviour and crystallization mechanism of a sodium sulphate sodium phosphate mixture in a heat storage system

The operating behaviour of a new salt hydrate mixture in a pilot heat storage unit using direct contact heat exchange has been investigated. The new storage medium is based on diluted Glauber's salt in which the excess water has been replaced by Na₂HPO₄ ? 12H₂O as an active participant in the storage process. Improved heat storage properties have been found with the new salt mixture. Sampling of the salt solution and deposited crystals during operation indicated that alternate independent crystallization of Glauber's salt and of the phosphate salt occurs. Simulations of the crystallization behaviour based on this assumed mechanism are described.     

Optimization of the heat plant of district energy systems

This paper presents a scheme to achieve structural and operational optimization for the heat plant in a district energy system. A district energy system consists of energy suppliers and consumers, district heating pipelines and heat storage facilities in a region. Production and consumption of energy and transport of energy as well as storage of heat are taken into account in the model. The problem is formulated as a mixed integer linear programming (MILP) problem where the objective is to minimize the overall cost of the district energy system. Evaluation of the energy production cost is based on the daily operation for every season at the plant located at Suseo in Seoul, Korea. From the results of numerical simulations we can see that the district energy system is well approximated by the proposed model, and that the energy efficiency is improved by the application of the optimal operation conditions provided by the proposed model.