计及光伏功率预测的配电网潮流计算

采用改进BP神经网络算法对光伏系统进行短期功率预测并计算其在配电网中的潮流问题,采用改进前推回代算法进行潮流计算,通过求解节点—分层矩阵来对系统分层,进而对每层节点进行前推回代计算系统有功网损。最后,利用改进BP神经网络算法对某日光伏系统进行功率预测,并采用改进前推回代算法计算33节点系统的潮流,算例分析验证了所提改进算法的准确性与预测模型的有效性与实用性。     

锅炉锅炉微机控制节能系统的改进

介绍了ＧＷＫ－０１型工业锅炉微机控制系统的改进措施以及改进后系统运行情况及其经济性。     

风扇磨煤机润滑系统的传热机理分析及改进设计

通过介绍风扇磨煤机润滑系统的改进设计方案、相应的计算方法以及润滑系统改进前、后效果的对比,证明了改造后的润滑系统具有明显的优越性。     

冷轧不锈钢BA板森吉米尔二十辊轧机的技术开发

对专用于轧制不锈钢BA板的森吉米尔二十辊冷轧机进行了工艺参数介绍。详细分析了该轧机相对于以往森吉米尔轧机在机械结构上的改进,主要包括轧制油过滤系统的改进、辊型径向调整机构中AS-U-Roll调整机构的改进以及液压系统的改进。     

DF11型机车柴油机隔振系统改进

对戚墅堰机车车辆厂DF11型机车柴油机隔振系统进行了改进研究,对改进前原有隔振系统进行了测试,提出了隔振器改进设计的思路和方法,并对改装6WN-8500型隔振器后进行了装车测试,对结果进行分析比较,证实了隔振器改进项目是成功的。     

乙烯液化气船再液化系统的改进研究

对当前乙烯液化气运输船的市场需求量和乙烯液化气船蒸发气回收的必要性进行了分析,对原有乙烯液化气船再液化系统工艺流程以及系统内乙烯蒸发气的流动状态和流动路线进行了定性描述,介绍了在原有系统工艺配置的基础上对乙烯液化气船再液化系统工艺流程进行的优化改进。将改进前和改进后的工艺流程图进行了理论对比,证明改进后的乙烯液化气船再液化系统结构更加紧凑,再液化循环结果更加节能。     

国产机车柴油机燃油喷射系统的改进

从国产机车柴油机的运用特点出发,根据国外的成功经验,对调车用机车柴油机供油系统进行了改进。为了提高国产干线主型机车柴油机燃油喷射系统工作可靠性、耐久性,对国产240系列柴油机的燃油系统进行了攻关改进,改进方案经过油泵台、多缸机、实际装车、扩大装车运用考核表明,改进达到了预期的目的,已于1998年1月通过部级鉴定。     

提升乘用车汽油机燃烧系统性能的研究

应用稳态CFD数值分析和气道稳流试验方法对某乘用车汽油机的原气道和改进气道进行了分析。计算和试验均表明:改进的进气道比原进气道流量系数降低14%,但滚流比提高56%;改进的排气道流量系数比原排气道提高10%。燃烧室也进行了减小最远火焰传播距离和降低面容比的改进。基于改进前后的燃烧系统进行了进气和压缩两冲程的瞬态CFD分析,结果表明:改进后的燃烧系统在缸内能形成更规则的大尺度漩涡,而且缸内瞬态滚流比更高,湍动能也高于原燃烧系统。最后通过试验进行了验证,结果表明:在外特性上,改进燃烧系统的点火提前角比原燃烧系统在中低速提前3～5°CA,高速时基本一致。改进燃烧系统的中低速扭矩比原燃烧系统提高4%～10%,部分负荷燃油消耗率降低5%～9%,高速时两者差别不大。     

谈国产内燃机车低压燃油系统改进的必要性

针对大功率国产内燃机车低压燃油系统在日常和实施燃油低烧1号柴油工程中存在的不足,阐述了对低压燃油系统改进的必要性,并给出了改进方案.     

6135AZLD电站柴油机设计开发及结构改进

介绍了6135系列电站用柴油机的结构改进、性能改进过程,并通过零部件优化设计,如曲轴、活塞组件、滤清系统和冷却系统,并进行了燃油系统和增压系统的匹配和优化,使整机性能最终满足开发要求。     

Multivariable adaptive control for a thermal generator

A digital control system using the optimal control has been developed for a thermal power generator. In order to increase the generator control performance for improving the power system stability, this system supplies the excitation system directly with control signals and provides the governor system with control signals and supplemental control signals for a conventional governor. The system utilizes adaptive control for changes in generator nonlinear characteristics, as well as in power system characteristics. The principles and application of this system are described and results of simulation tests using a 1000 MVA thermal power plant model on a high-reliability AC/DC electric power system simulator are presented. The results verify the performance of this system, as well as the applicability of the system to actual plants     

PEMFC分布式发电系统动态协调控制仿真

符号表m-质量/kg W-质量流量/kg·s-1N-电池个数I-电流/AM-摩尔分子质量F-法拉第常数/kg·mol-1/9.6 487×104C·mol-1R-气体常数/J·(mol·K)-1T-温度/KV-体积/m3A-反应面积/m2nd-电渗透系数Dw-扩散系数/m2·s-1cwa、cwc-膜阳极侧和阴极tm-膜厚度/m侧的水浓度/mol·m-2kp-水力     

An integrated domestic refrigerator and hot water system

This paper presents a new design of a prototype refrigeration-cum-hot water heating system for domestic use. The system uses the heat energy rejected from the compressor and condenser of a vapour-compression refrigerator by storing it in a heat sink. This energy is then transferred to mains water entering the hot water cylinder, where the water temperature is boosted by an electric resistance heater to a preset temperature for domestic usage. A prototype system of such a configuration was assembled as an integrated unit with the refrigerator adjacent to the water tank. The system is called the Home Energy Centre (HEC). Power consumption and temperature distribution were measured for standing and draw off tests using the unit as a conventional hot water cylinder, refrigerator or as the combined system. A new parameter, ϕ, is defined to compare the system performance as the HEC prototype against its performance when working only as a refrigerator or a water heater. The system performed better as the prototype than it did as a hot water heater, but needs to be improved further to fully explore its expected potential. © 1998 John Wiley & Sons, Ltd.     

Optimal green energy management for island resorts in Malaysia

This paper proposes optimum green energy systems for electricity generation of island resorts in Malaysia. A combination of solar energy and wind energy as intermittent renewable energy sources with a fuel cell (FC) system and a battery storage energy system as a backup to the green energy system is introduced for this study. This system is eco-friendly, economical over the long-term, highly sustainable and reliable. In addition, a diesel-based energy system as a non-green system is compared with the proposed green system. National Renewable Energy Laboratory's (NREL) HOMER software is used to determine and compare the optimal configuration green energy system with the diesel-based energy system in terms of net present cost, sensitivity analysis and pollutant gas emission. The feasibility and assessment of the proposed system is evaluated by utilizing the load profile and considering the geographical condition of a village (Juara village in Tioman Island) with approximately 30 chalets located in southern Malaysia. HOMER uses two types of load profiles for each given year. The first load profile is used during the presence of tourists, and the second profile is used when the locals are the main inhabitants of the island. The optimization management for the green energy system is performed through unit sizing to find the optimum power management analysis and to perform cost analysis of the system.The potential of renewable energy as well as a diesel-based energy system to meet the power demand for such a stand-alone system is considered. Technically feasible and economically viable green energy systems as prospective plans are explored in this study.     

固体氧化物燃料电池与燃气轮机混合发电系统

基于固体氧化物燃料电池系统的高效率、环保性以及排气废热的巨大利用潜能,将其与燃气轮机组成混合发电装置,是一种极有前景的分布式发电方案.文章以SWP公司的加压型SOFC-小型燃气轮机混合循环系统为例,对固体氧化物燃料电池及燃气轮机混合循环系统的原理及发展现状作了分析,为我国固体氧化物燃料电池-燃气轮机混合循环系统的研制提供参考.     

Spark spread – A screening parameter for combined heating and power systems

Combined heating and power (CHP) systems may be considered for installation if they produce savings over conventional systems with separate heating and power. For a CHP system with a natural gas engine as the prime mover, the difference between the price of natural gas and the price of purchased electricity, called spark spread, is an indicator as to whether a CHP system might be considered or not. The objective of this paper is to develop a detailed model, based on the spark spread, that compares the electrical energy and heat energy produced by a CHP system against the same amounts of energy produced by a traditional, or separate heating and power (SHP) system that purchases electricity from the grid. An expression for the spark spread based on the cost of the fuel and some of the CHP system efficiencies is presented in this paper as well as an expression for the payback period for a given capital cost and spark spread. The developed expressions allow determining the required spark spread for a CHP system to produce a net operational savings over the SHP in terms of the performance of system components. Results indicate that the spark spread which might indicate favorable payback varies based on the efficiencies of the CHP system components and the desired payback period. In addition, a new expression for calculating the payback period for a CHP system based on the CHP system capital cost per unit of power output and fuel cost is proposed.     

基于DeviceNet现场总线的快速热处理设备控制系统设计

介绍了一种基于DeviceNet现场总线的快速热处理设备控制系统。首先介绍了该系统的硬件构成,本控制系统采用了基于现场总线和模块化设计思想,使得该系统的能够满足快速热处理设备的加热腔的数量可任意配置,具有很好的可扩展性;然后提出了一个分层的、模块化的、可配置的软件控制系统,并对其进行了简要概述;最后设计了一个基于系统模型的温度控制器,该控制器采用了前馈控制与反馈控制相结合的方法,其中,前馈通道用来预测控制输出,从而提高了系统响应速度;反馈通道用来修正模型误差和外界干扰,从而提高了控制系统的鲁棒性和控制精度。     

Integrated battery controller for distributed energy system

In this article, an improved integrated battery energy storage system (BESS) controller for distributed energy system is presented. The BESS is integrated in parallel with the full wave bridge converter into the distributed energy system network. In a normal operating mode, the BESS serves as a power conditioner as well as an active power filter in a distributed power system network. This work presents BESS controller which is designed for regulating the state of charge of the batteries and also to manage the active power in a distributed power system network. The off peak load energy is used to recover the batteries’ state of charge through the BESS controller. In this BESS controller, the constant current-constant voltage (CC-CV) mode is used and it helps to keep the batteries’ state of charge conditions for improving the reliability of the distributed power system system. This control strategy is incorporated into the main converter. The controller helps in managing the phase, amplitude and waveform of the current and voltage on the distributed power system network. The controller ensures the power quality and also assists in improving the power factor with respect to the utility for the intermittent distributed generation as well as the load. In this article, the test results of a prototype system are presented, which validates the proposed controller strategy of BESS in a distributed power system network.     

Simulation of a hybrid vehicle powertrain having direct methanol fuel cell system through a semi-theoretical approach

Different operating scenarios can be used in a hybrid system based on a direct methanol fuel cell (DMFC) and a battery. In this paper, a DMFC system model is integrated into a model formed for a hybrid vehicular system that consists of a battery, a DMFC stack and its auxiliary equipments; and the model is simulated in Matlab/Simulink environment using a quasistatic approach. An algorithm for the energy management of the system is also developed considering the state of charge (SOC) of the battery. In the DMFC system model, the current and empirical data for the polarization curves as well as methanol crossover and water crossover rates are taken as the input parameters, whereas the stack voltage, the remaining methanol in the fuel tank, and the power demand of auxiliary equipments are taken as the output parameters. In this model, the methanol consumption, and the water and CO₂ production are found applying mass balances for each component of the system. The results of the simulations help to give more insights into the operation of a DMFC based hybrid system.