超临界锅炉单相受热面不同动态数学模型的比较

根据600MW超临界直流锅炉再热器系统和过热器系统的具体特点,对锅炉再热器系统和过热器系统建立了3种不同的集总参数动态数学模型,并编制程序进行了仿真计算,得到烟气挡板调节再热汽温时,采用不同模型时再热汽温和过热汽温的动态特性,并对其动态特性进行比较,研究适合超临界锅炉再热器系统和过热器系统的数学模型。     

太阳能热水地板采暖系统稳态换热过程的研究

本文以太阳能热水地板采暖系统为研究对象,对地板和房间做了综合换热分析,建立了系统的数学模型,并利用计算机进行数值求解。实验证明,本文建立的数学模型基本正确,提出的计算程序可以模拟此系统的换热过程,对不同情况下的系统设计和运行具有指导意义。     

发电厂计算机监控系统调频仿真

本文以华中某大型水电站计算机监控系统为对象进行调频模式的仿真研究。先建立不同类型电厂的数学模型,再作网络简化,用同步功率系数表征小被动下的网络特性,求得电力系统的简化数学模型,据此进行仿真计算求出较佳的计算机监控系统参数。     

基于MATLAB的风力发电机组建模和仿真研究

变桨距控制技术是风力发电机组提高对风能的利用的有效方法,由于外界环境的随机性和控制变量的多样性,风力发电系统是一个非线性的系统,其数学模型的建立和仿真是一个难点。本文基于Matlab软件平台,采用机理建模法建立了风力发电机组的各个分系统的子模型,组合成整个机组的数学模型,并采用PID控制算法实现风力发电机组在不同风速下对风能利用的最大化,仿真结果验证了系统模型和控制算法的正确性,为风机控制的创新奠定了理论基础。     

带尾水电站母管制循环水系统优化运行的研究

以火电厂带尾水电站的循环水系统为对象,建立了优化运行的数学模型,提出了求解算法,并针对某厂300MW机组,通过计算得到了不同负荷下系统的最优运行方式。     

从节能率看燃气冷热电联产的热经济性

建立了冷热电三联产系统与三分产系统节能率比较的数学模型。通过对以不同的燃气轮机、吸收式制冷机、汽轮机等组成不同模式下的三联产系统节能率的计算分析了影响冷热电联产节能性的因素,并以临界煤耗率作为判断冷热电联产是否节能的条件。     

干熄炉-锅炉系统节能降耗的对策研究

在全面系统地分析了国内外有关干熄炉-锅炉系统主要节能技术措施的基础上,提出了在循环风机出口处增设“纯水热交换器”的技术方案。利用所建立的干熄炉数学模型、干熄锅炉数学模型、循环气体燃烧过程数学模型、纯水热交换器内热过程数学模型和除氧器内热过程等数学模型开发出了“干熄炉-锅炉系统全流程计算机数值仿真系统”,并根据某公司干熄炉-锅炉系统的实际生产情况,利用该仿真系统软件进行了数值优化计算,分析了增设“纯水热交换器”后对全系统节能降耗主要技术经济指标的影响。     

微燃机冷热电联供系统性能的模拟研究

介绍了冷热电联供(CCHP)系统,以上海某示范性微燃机冷热电联供系统为研究对象,通过建立系统主要设备的数学模型,模拟分析了系统在不同环境温度下的性能和系统全年的运行工况。结果表明:微燃机冷热电联供系统的性能受环境温度的影响,系统过渡季节不运行时年平均能源综合利用率可达到70%以上。     

兆瓦风力发电机系统可靠性设计理论研究

在分析兆瓦风力发电机系统的基础上,提出了兆瓦风力发电机发电系统可靠度的基本概念及计算方法,建立了可靠度最优分配的数学模型及最优兆瓦风机发电系统可靠性设计的数学模型。     

太阳能集热系统过热影响因素分析

通过分析太阳能供热系统集热、蓄热和用热各个子系统的动态热量热平衡关系,建立太阳能集热系统热量传递数学模型,并结合集热系统内部流体过热汽化原理,提出集热系统过热度评价指标,并对集热系统在不同流量、水箱容积以及不同连接方式等条件下的过热程度进行分析计算。结果表明,集热系统过热度随热媒流量、集热器倾角和水箱容积取值的增大而减小,并通过对上述3种因素进行敏感性分析得到集热器倾角对系统过热度的影响最大。     

Neural network-based energy management of multi-source (battery/UC/FC) powered electric vehicle

Due to increased environmental pollution and global warming concerns, the use of energy storage units that can be supported by renewable energy resources in transportation becomes more of an issue and plays a vital role in terms of clean energy solutions. However, utilization of multiple energy storage units together in an electric vehicle makes the powertrain system more complex and difficult to control. For this reason, the present study proposes an advanced energy management strategy (EMS) for range extended battery electric vehicles (BEVs) with complex powertrain structure. Hybrid energy storage system (HESS) consists of battery, ultra-capacitor (UC), fuel cell (FC) and the vehicle is propelled with two complementary propulsion machines. To increase powertrain efficiency, traction power is simultaneously shared at different rates by propulsion machines. Propulsion powers are shared by HESS units according to following objectives: extending battery lifetime, utilizing UC and FC effectively. Primarily, to optimize the power split in HESS, a convex optimization problem is formulated to meet given objectives that results 5 years prolonged battery lifetime. However, convex optimization of complex systems can be arduous due to the excessive number of parameters that has to be taken into consideration and not all systems are suitable for linearization. Therefore, a neural network (NN)-based machine learning (ML) algorithm is proposed to solve multi-objective energy management problem. Proposed NN model is trained with convex optimization outputs and according to the simulation results the trained NN model solves the optimization problem within 92.5% of the convex optimization one.     

重型载货车动力总成优化匹配研究

采用AVL-Cruise软件对某款重型载货车进行建模,比较基本型试验数据与仿真数据并通过了符合性验证。通过整车动力总成的优化匹配分析,进行发动机及动力传动零件优化计算,提出动力总成的优化方案,并实际装车进行试验验证。     

Control strategy of a fuel-cell power module for electric forklift

Fuel cell-battery hybrid systems for the powertrain, which have the advantage of emission-free power generation and adapt to material transport and emission reduction, are investigated. Based on the characteristics of the fuel cell system and the characteristics of the electric forklift truck powertrain system, this work defines the design principle of the control strategy to improve overall performance and economy. A simulation platform for fuel cell and electric vehicles has been established. The optimal performance of the fuel cell stack and the battery capacity were defined for the specific application. An energy control strategy was defined for different operating cycles and operating conditions. Model validation involved comparing simulation results with experimental data obtained during VDI60 test protocol. The main parameters that influence the forklift performance were defined and evaluated, such as energy loss, fuel cell operating conditions and different battery charging cycles. The optimal size of the fuel cell stack of 11 kW and the battery of 10 Ah was determined for the specific load profile with the proposed control strategy. The results obtained in this work forms the basis for an in-depth study of the energy management of fuel cell battery drive trains for forklift trucks.     

基于Cruise的客车动力总成匹配及仿真分析

介绍了运用AVL公司Cruise软件对客车动力匹配进行模拟计算。该软件将发动机、变速箱、后桥等影响整车动力性、经济性的相关因素整合成一整套动力总成系统。通过大量的实践证明,这种对于动力总成系统的优化,可以更好满足整车厂对于整车经济型和动力型的要求。     

混合动力系统状态切换技术研究

基于模块化思想,针对混合动力系统开发的特点,在AVL PUMA Open动态测试系统的基础上搭建了混合动力系统试验台架.针对混合动力系统中关键技术之一的状态切换问题进行研究,提出相应的控制策略,并在混合动力系统试验台架上对状态切换的策略进行验证.试验表明,采用发动机转矩在线估计的动态控制方法能够有效地解决状态切换过程中出现的转矩突变问题,转矩波动的相对幅度可以控制在5%左右.     

Analysis of dc link oscillations in a hybrid fuel cell powertrain brought by in situ converter based electrochemical impedance spectroscopy

Electrochemical impedance spectroscopy (EIS) is a valuable tool for characterizing fuel cells. It was previously used for offline testing and only applied to single cells or short stacks with low-power equipment. Recently, there has been a trend on bringing it to high-power fuel cell stacks (FCSs) for in situ operation, especially in vehicular applications, with the required EIS ac perturbations generated by the power processing converter. However, the effects of adding such an extra function to a converter in the powertrain have not been investigated previously. Aiming at filling this gap, this paper focuses on the oscillations brought by the converter based EIS operation and their transfer in a typical hybrid fuel cell powertrain. The presented results indicate that it is favorable to operate EIS during motor is idling. The oscillation on the dc link reaches its maximum at the resonant frequency of the energy storage converter, while its magnitude is influenced by various factors, i.e., system parameters and operating conditions. Moreover, it is found that the worst-case condition of oscillation can be determined by a healthy stack at the beginning of its life.     

On-line fuzzy energy management for hybrid fuel cell systems

Fuel Cell Hybrid Vehicles (FCHV) can reach near zero emission by removing the conventional internal combustion from the vehicle powertrain. Nevertheless, before seeing competitive and efficient FCHV on the market, at market prices, different technical, economic, and social challenges should be overcome. A typical hybrid fuel cell powertrain combines a fuel cell stack and a dedicated energy storage system along with their necessary power converters. Energy storage systems are used in order to enhance the well-to-wheel efficiency and thus reducing the hydrogen consumption. An efficient management of power flows on the vehicle, allows optimizing the recovery of energy braking. Moreover, working in the fuel cell maximum efficiency leads to reduced thermal losses and thus to the downsizing of the heat exchangers. This paper presents an enhanced control of the power flows on a FCHV in order to reduce the hydrogen consumption, by generating and storing the electrical energy only at the most suitable moments on a given driving cycle. While the off-line optimization-based on dynamic programming algorithm offers the necessary optimal comparison reference on a known demand, the proposed strategy which can be implemented on-line, is based on a fuzzy logic decision system. The fine tuning of the fuzzy system parameters (mainly the membership functions and the gains), is made using a genetic algorithm and the fuzzy supervisor shows performing results for different load profiles.     

基于重型并联混合动力车辆混合度的性能分析

动力系统的匹配直接关系到车辆的性能,在对混合动力车辆的研究中有着非常重要的地位,而混合度的研究是动力系统匹配中的关键.本文基于已选定的额定功率为220kw的柴油发动机,对混合动力车辆的电机进行匹配,对不同混合度下的车辆模型进行性能分析.通过Avl-Cruise软件对各混合度下的车辆模型进行仿真对比,选用等效油耗以及比排放量为评价指标,对不同混合度下混合动力车辆的性能进行了比较,研究了随着混合度的变化,车辆的经济性以及排放性能变化的规律,提出了适用于本混合动力系统的最佳混合度.     

Fuel cell hybrid powertrains for use in Southern Italian railways

This paper analyses the use of a fuel cell hybrid powertrain for different uses on rail. Four vehicles are numerically tested on suitable tracks. The implemented model calculates the vehicle power demand, starting from track altitude, train speed and vehicle characteristics. For each track, a powertrain composed of a fuel cell system and an energy storage system, battery and/or supercapacitor, is used, suitable for the purpose. Each component is modelled separately and is validated. It should be underlined that the whole system is validated, by means of experimental data found in the literature. A comparison analysis between the simulation results is done: the H₂ consumption varies between 5 kg/cycle and 160 kg/cycle, according to the track energy consumption, while the fuel cell efficiency is between 50% and 47%, since the fuel cell works at different power rates.     

重型自卸车动力总成悬置优化设计

为降低重型自卸车底盘振动,提高乘坐舒适性,建立了动力总成四点悬置系统模型.利用打击中心和能量解耦理论对悬置软垫的位置及刚度进行了优化,计算并分析了优化前后动力总成悬置系统的模态频率及能量分布.优化后动力总成悬置系统模态频率有效地避开了发动机的怠速激励从而避免了共振,同时各自由度下的解耦率也大幅提高.通过定置试验对优化方...