混合动力重卡自适应等效燃油消耗最小化能量管理策略北大核心CSCD

为解决等效燃油消耗最小化策略的关键参数在不同工况下的动态调整,提出一种适用于混合动力重型汽车的自适应等效燃油消耗最小化策略(adaptive equivalent consumption minimization strategy,A-ECMS)。该策略以层次聚类算法得到的6种典型行驶工况为例,提出了一种基于神经网络工况识别算法。应用改进的混沌粒子群优化(chaosparticle swarm optimization,CPSO)算法优化特定驾驶循环下等效燃油消耗最小化策略(equivalent consumption minimization strategy,ECMS)的3个关键参数:等效因子、惩罚函数的比例因子和发动机起动车速阈值。提出了一种基于工况识别的新型自适应能量管理策略对关键参数进行优化,根据该重型卡车的传动系统构型,建立了车辆的纵向动力学模型,并通过仿真进行了验证。仿真结果表明复合工况驱动循环下的CPSO-ECMS和A-ECMS控制策略与传统等效燃油消耗策略相比,油耗分别降低了5.9%和8.9%。     

基于深度强化学习的增程式电动轻卡能量管理策略

为了解决增程式电动轻卡辅助动力单元（auxiliary power units, APU）和动力电池之间能量的合理分配问题,在Simulink中建立面向控制的仿真模型,并提出一种基于双延迟深度确定性策略梯度（twin delayed deep deterministic policy gradient, TD3）算法的实时能量管理策略,以发动机燃油消耗量、电池荷电状态（state of charge, SOC）变化等为优化目标,在世界轻型车辆测试程序（world light vehicle test procedure, WLTP）中对深度强化学习智能体进行训练。仿真结果表明,利用不同工况验证了基于TD3算法的能量管理策略（energy management strategy, EMS）具有较好的稳定性和适应性;TD3算法实现对发动机转速和转矩连续控制,使得输出功率更加平滑。将基于TD3算法的EMS与基于传统深度Q网络（deep Q-network,DQN）算法和深度确定性策略梯度（deep deterministic policy gradient, DDPG）算法进行对比分析,结果...     

基于粒子群算法的最小二乘支持向量机电池状态估计CSCD

电池荷电状态(SOC)作为电池管理系统(BMS)重要参数之一,准确估计SOC尤为重要。由于SOC在估计过程中常会受到电压、电流、充放电效率等众多因素的影响,因此很难准确估计SOC。为了提高SOC的估计精度,本工作提出了基于最小二乘支持向量机(LSSVM)机器学习的锂离子电池SOC估计模型。将该电池的电流、电压和温度作为模型的输入向量,SOC作为模型的输出向量,为了更好的获得LSSVM模型的参数,提出了利用自适应粒子群算法来进行参数优化,从而获得高精度SOC估计模型。通过恒流充放电实验采集的数据,并和未优化的粒子群优化的LSSVM、支持向量机(SVM)神经网络(NN)相比,所提模型的SOC估计精度误差为1.63%,验证了算法的有效性。     

复合翼无人机混合动力系统能量管理策略设计

以某最大起飞质量为25 kg的复合翼无人机混合动力系统为研究对象,基于MATLAB/Simulink平台搭建动力系统关键部件数学模型、集成复合翼无人机混合动力系统级仿真模型,依据复合翼无人机在多点悬停作业场景下的飞行任务要求,设计相应的飞行任务剖面与基于等效燃油最小消耗的能量管理策略,进行仿真试验验证。结果表明：基于等效燃油最小消耗能量管理策略的无人机动力系统的油门跟随性良好,满足无人机实际运行需要;动力电池荷电状态可以维持在设定值附近,相对误差小于1.5%;相比基于规则的能量管理策略,基于等效燃油最小消耗管理策略的混合动力系统无人机在点对点飞行和多点悬停作业2种飞行工况下的燃油消耗分别下降了6.07%、5.49%。     

基于拥挤距离的多目标粒子群优化算法在漳河水库优化调度中的应用

针对传统多目标优化算法的不足,提出了基于拥挤距离的多目标粒子群优化算法(MOPSO CD),该算法用拥挤距离来维持精英策略和选取全局极值,同时引入动态非均匀变异算子,用以维持粒子多样性、减缓算法收敛速度、避免早熟收敛。以漳河水库为例,建立了以灌溉缺水量最小和发电量最大为目标函数的两目标优化调度模型,将MOPSO CD应用于模型的求解中,得到了足够多且较均匀的非劣（Pareto）解前端。     

氢燃料电池船舶能量管理策略

基于规则与基于功率跟随的控制方式分别设计氢燃料电池船舶能量管理策略,并对所设计的能量管理策略进行仿真分析。结果表明所设计的2种能量管理策略在船舶运营时能够满足锂电池的充电需求,维持锂电池荷电状态（state of charge,SOC）在合理范围内。与基于规则的能量管理策略相比,当采用能量跟随的能量管理策略时动力系统所需的锂电池容量更小,燃料电池工作点波动更频繁。     

基于SOC均衡的分布式电池储能系统协同控制策略

研究分布式电池储能系统的优化控制方法以及电池荷电状态（SOC）均衡策略,提出基于SOC均衡的协同控制策略。利用多智能体系统（MAS）理论,实现电池储能系统的协同控制,并采用多智能体分布式算法,实现功率指令的自适应分配,进而实现SOC动态均衡。针对传统多智能体算法收敛速度较慢的问题,提出一种基于模型预测控制（MPC）的分布式算法,利用MPC对传统多智能体算法进行优化,提高收敛速度。最后利用实际储能功率数据进行仿真,验证了所提策略的有效性和算法在收敛速度上的优势。     

油电混合动力无人机能量管理策略的对比仿真研究

针对固定飞行任务的油电混合动力无人机,降低混合动力系统瞬时燃油消耗率,增加续航里程的工作需求,设计了可以应用于固定飞行任务油电混合动力无人机的不同能量管理策略,主要包括固定规则、模糊逻辑和动态规划算法的能量管理策略。根据油电混合动力无人机动力源特性,通过理论和试验建模相结合的方法,在MATLAB中建立油电混合动力系统的数学模型、飞行任务相对应的仿真工况及不同能量管理策略的控制程序。重点对比了基于优化的动态规划算法能量管理策略相比固定规则和模糊逻辑策略在燃油经济性和运行稳定性方面的表现。仿真结果表明：动态规划算法策略的累积燃油消耗量相比固定规则、模糊逻辑策略分别下降了4.6%和6.5%,平均瞬时燃油消耗率分别下降了5.1%和5.9%;在应对外部突风扰动时,动态规划能量管理策略的航空发动机最大转速波动相比固定规则的能量管理策略下降了59.7%,应对随机紊流扰动时,动态规划策略航空发动机的最大转速波动相比固定规则和模糊逻辑分别下降了33.9%、25.6%。动态算法作为一种全局最优算法,应用在固定飞行任务的油电混合动力无人机能量管理策略中时,可在提高混合动力系统燃油经济性的同时保证系统运行的稳定性。     

基于分布式发电的储能系统能量管理策略

针对传统能量管理策略经济性差、调峰能力弱的问题，提出一种基于分布式发电的储能系统（ESS）能量管理策略。首先结合Pareto最优理论，建立以降低能源成本与平滑负荷峰谷效应为目标的需求侧优化调度模型。在首次优化过程中，采用具有自适应变异与动态更新惯性权重功能的改进粒子群算法（IPSO）求解最优经济指标。进而以该指标作为约束，对调度区间进行划分，实现目标的完全解耦，并引入惩罚函数获得增广目标函数。最终通过贪婪算法（GA）进行二次优化，可求得在最佳经济效益的前提下最大程度平滑负荷峰谷效应的非支配调度向量。仿真结果表明：IPSO具有较高的收敛速度与精度，所提策略在3种场景下分别降低用电成本18.6%、32.8%、17.3%，负荷峰均较首次优化降低21.2%、10.3%、20.1%，并通过多场景数据集下的仿真验证了结论的普适性。     

基于模糊控制的燃料电池列车能量管理研究

能量管理策略是燃料电池混合动力列车的一个关键技术。在现有模糊控制策略的基础上,文中提出一种基于粒子群算法的模糊控制能量管理策略,介绍该策略的工作方法及实现过程。仿真表明,该策略不仅能实现燃料电池混合动力机车的能量管理,还能降低燃料的损耗。     

Ash-forming elements in four Scandinavian wood species. Part 1: Summer harvest

Woody biomass in Finland and Sweden comprises mainly four wood species: spruce, pine, birch and aspen. To study the ash, which may cause problems for the combustion device, one tree of each species were cut down and prepared for comparisons with fuel samples. Well-defined samples of wood, bark and foliage were analyzed on 11 ash-forming elements: Si, Al, Fe, Ca, Mg, Mn, Na, K, P, S and Cl. The ash content in the wood tissues (0.2–0.7%) was low compared to the ash content in the bark tissues (1.9–6.4%) and the foliage (2.4–7.7%). The woods’ content of ash-forming elements was consequently low; the highest contents were of Ca (410–1340 ppm) and K (200–1310), followed by Mg (70–290), Mn (15–240) and P (0–350). Present in the wood was also Si (50–190), S (50–200) and Cl (30–110). The bark tissues showed much higher element contents; Ca (4800–19,100 ppm) and K (1600–6400) were the dominating elements, followed by Mg (210–2400), P (210–1200), Mn (110–1100) and S (310–750), but the Cl contents (40–330) were only moderately higher in the bark than in the wood. The young foliage (shoots and deciduous leaves) had the highest K (7100–25,000 ppm), P (1600–5300) and S (1100–2600) contents of all tissues, while the shoots of spruce had the highest Cl contents (820–1360) and its needles the highest Si content (5000–11,300). This paper presented a new approach in fuel characterization: the method excludes the presence of impurities, and focus on different categories of plant tissues. This made it possible to discuss the contents of ash element in a wide spectrum of fuel-types, which are of large importance for the energy production in Finland and Sweden.     

NEXT GENERATION ENGINEERED MATERIALS FOR ULTRA SUPERCRITICAL STEAM TURBINES

正1 ABSTRACT To reduce the effect of global warming on our climate,the levels of CO2emissions should be reduced.One way to do this is to increase the efficiency of electricity production from fossil fuels.This will in turn reduce the amount of CO2emissions for a given power output.Using US practice for efficiency calculations,then a move from a typical US plant running at 37%efficiency to a 760℃/38.5 MPa(1 400/5 580 psi)plant running at 48%efficiency would reduce CO2emissions by 170kg/MW.hr or 25%.     

Aerodynamic performance effects of leading-edge geometry in gas-turbine blades

The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°,   −5°,   +5°,   +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods.     

Hydrogen production by steam-gasification of carbonaceous materials using concentrated solar energy – V. Reactor modeling,optimization, and scale-up

A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified.     

Contents in Volume 23,2014

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汽轮机数字电液调节系统挂闸异常的技术完善

分析了200MW汽轮机数字电液调节系统在运行中存在的挂闸异常问题,采取了相应的技术处理措施,且运行实践效果良好。     

新型高压共轨ECU升压模块的数字化开发与优化

为了提高喷油器电磁阀的响应速率,提出了一种基于CPLD(复杂可编程逻辑器件)应用于高压共轨ECU的数字升压模块。鉴于该升压电路结构参数多,其升压电压的恢复响应要求高等特征,基于Pspice建立了升压电路的仿真模型,研究了不同电路参数下升压模块的输出特性,全面优化了该升压模块的性能。结果显示,该升压模块的最大转换效率可以达90%以上。在柴油发动机上对ECU的试验表明,升压电压最大波动不超过10%,其恢复时间仅为1.3ms,功率管最大温升仅为41℃,满足整机运行范围内ECU的需求。     

Trace metal chemistry and silicification of microorganisms in geothermal sinter, Taupo Volcanic Zone, New Zealand

As part of a pilot study investigating the role of microorganisms in the immobilisation of As, Sb, B, Tl and Hg, the inorganic geochemistry of seven different active sinter deposits and their contact fluids were characterised. A comprehensive series of sequential extractions for a suite of trace elements was carried out on siliceous sinter and a mixed silica-carbonate sinter. The extractions showed whether metals were loosely exchangeable or bound to carbonate, oxide, organic or crystalline fractions. Hyperthermophilic microbial communities associated with sinters deposited from high temperature (92–94°C) fluids at a variety of geothermal sources were investigated using SEM. The rapidity and style of silicification of the hyperthermophiles can be correlated with the dissolved silica content of the fluid. Although high concentrations of Hg and Tl were found associated with the organic fraction of the sinters, there was no evidence to suggest that any of the heavy metals were associated preferentially with the hyperthermophiles at the high temperature (92–94°C) ends of the terrestrial thermal spring ecosystems studied.     

Assessment methods of material ageing using Sdobyrev''s creep rupture model

The physical aspects of the activation energy, in higher and high temperatures, of the metal creep process were examined. The research results of creep-rupture in a uniaxial stress state and the criterion of creep-rupture in biaxial stress states, at two temperatures, are then presented. For these studies creep-rupture, taking case iron as an example the energy and pseudoenergy activation was determined. For complex stress states the criterion of creep-rupture was taken to be Sdobyrev's, i.e. σ_red = σ₁ β + (1 − β)σ_i, where: σ₁-maximal principal stress, σ_i-stress intensity, β-material constant (at variable temperature β = β(T)). The methods of assessment of the material ageing grade are given in percentages of ageing of new material in the following mechanical properties: 1) creep strength in uniaxial stress state, 2) activation energy in uniaxial stress state, 3) criterion creep strength in complex stress states, 4) activation pseudoenergy in complex stress states. The methods 1) and 3) are the relatively simplest because they result from experimental investigations only at nominal temperature of the structure work, however, for methods 2) and 4) it is necessary to perform the experimental investigations at least at two temperatures.     

Production of hydrogen from sewage biosolids in a continuously fed bioreactor: Effect of hydraulic retention time and sparging

Hydrogen was produced from primary sewage biosolids via mesophilic anaerobic fermentation in a continuously fed bioreactor. Prior to fermentation the sewage biosolids were heated to 70 °C for 1 h to inactivate methanogens and during fermentation a cellulose degrading enzyme was added to improve substrate availability. Hydraulic retention times (HRT) of 18, 24, 36 and 48 h were evaluated for the duration of hydrogen production. Without sparging a hydraulic retention time of 24 h resulted in the longest period of hydrogen production (3 days), during which a hydrogen yield of 21.9 L H₂ kg⁻¹ VS added to the bioreactor was achieved. Methods of preventing the decline of hydrogen production during continuous fermentation were evaluated. Of the techniques evaluated using nitrogen gas to sparge the bioreactor contents proved to be more effective than flushing just the headspace of the bioreactor. Sparging at 0.06 L L min⁻¹ successfully prevented a decline in hydrogen production and resulted in a yield of 27.0  L H₂ kg⁻¹ VS added, over a period of greater than 12 days or 12 HRT. The use of sparging also delayed the build up of acetic acid in the bioreactor, suggesting that it serves to inhibit homoacetogenesis and thus maintain hydrogen production.