增程式电动汽车动力系统一体化冷却传热分析

以一款增程式轻型卡车为研究对象,对增程式动力系统的发动机和电机采用一体化冷却系统设计。在预设的运行工况,通过试验测试,计算出工况点增程器和电驱系统的散热需求,对冷却液和冷却水泵进行选型匹配。结合试验测试建立了增程器和电驱系统冷却回路一维仿真模型,对比分析了电驱系统冷却管道串联与并联的冷却效果与能耗情况,验证了驱动电机冷却液帮助发动机冷起动的可行性。研究结果表明：通过试验测量散热量选择到的电子水泵,能更加高效准确地控制冷却液流量,冷却效果更好。冷却系统一维仿真分析中能从温升曲线直观看到并联冷却管路冷却效果更好,并联管路中的电磁阀根据工况不同控制开口大小,比串联管路统一控制冷却液流量冷却更高效。并联冷却管路中驱动电机冷却时快速产生热量,在与发动机冷起动时进行热交互可以帮助发动机快速暖机,改善发动机冷起动排放差、动力弱的情况。     

增程式电动汽车用LPG直喷发动机燃烧过程的数值解析

提出一种以LPG为燃料的适用于增程式电动汽车发电机组的二冲程缸内直喷发动机喷雾-壁面复合引导式燃烧系统。在采用纹影实验法对计算方法的可行性进行验证的基础上,分别对不同喷油时刻、不同曲轴转角的缸内混合气形成及燃烧情况进行了数值解析。结果表明:在起动-过渡运转工况(2 000 r/min、20%负荷)下,喷油开始时刻为45°CA ABDC、曲轴转到20°CA BTDC时,缸内能形成较为稳定的均质混合气。在20°CA BTDC时点火,放热率峰值最高,且峰值一般出现在上止点附近,燃烧特性最好。     

一种鲁棒自适应水轮机调速器

本文提出了一种鲁棒性较强的自适应调速器,它是将模型参考自适应方法和Robust控制方法相结合,同时只将对象的输入和输出信息用于水轮机调节,使得整个系统的适应能力,稳定性及动态品质都有所提高。数值仿真表明,用该方案设计出的调速器具有较强的鲁棒性。     

增程式乘用车动力选型与控制策略建模

基于某款增程式乘用车的动力性指标对驱动电机、发电机、电池及发动机等进行选型,采用AVL Cruise搭建车辆模型,Simulink建立控制策略模型,通过联合仿真实现车辆性能的仿真计算,结论如下:在WLTC循环中,采用增程式的循环油耗较传统车下降约21％,WLTC循环前3个阶段的平均车速较低,采用增程式对油耗改善明显,原...     

电子节气门开度鲁棒自适应控制器设计

为解决电感和负载转矩扰动对电子节气门鲁棒自适应控制的影响,将电感的影响等效为未知常值电压,将负载转矩扰动的影响等效为白噪声,建立电子节气门动态方程,并基于李亚普诺夫函数设计电子节气门开度鲁棒自适应控制策略。以某电子节气门为例,在电子节气门控制仿真系统中依次输入常数信号、阶跃信号、正弦信号,分别模拟汽车匀速行驶、急加速、连续变速3种工况,进行数值仿真验证。结果表明：该控制策略可将电感和负载转矩扰动对电子节气门开度控制精度的影响控制在抑制水平内;3种工况下节气门开度均能快速、精确地跟踪目标开度,且达到稳态后跟踪误差基本维持在0°附近。     

增程式混合动力商用车系统匹配及仿真研究

以某增程式混合动力商用车为例,对主要部件进行了计算选型。在此基础上采用GT-SUITE软件搭建了整车模型,最终进行整车匹配仿真计算。仿真研究表明,增程式混合动力汽车在合理设计下可以满足整车的动力性要求,同时相比传统燃油车,增程式混合动力汽车可大幅度降低整车油耗,其中中国货车行驶工况(CHTC-HT)节油率可达26. 09%。     

风力发电机速度跟踪自适应控制研究

为风力发电系统设计了全程速度跟踪自适应控制器,以保证风轮机的转子转速在整个风速全程变化范围内都能迅速跟踪上给定的希望速度,希望的速度曲线是根据考虑了风速大小、转子所允许的最大转速和额定功率将风轮机转子转速划分为3个不同的运行区域给出的,在这3个区域中可保证风力发电机最大程度的获取风能,同时又可安全可靠运行.理论推导和仿真研究结果均表明,所设计的控制器能驱使闭环风力发电系统在整个运行过程中很好地跟踪所给定的速度曲线,从而实现了最大利用风能且安全运行的设计目的.     

电动汽车增程器动态转矩控制研究

为了降低增程式电动汽车的转矩波动,改善车辆的NVH等问题,基于某增程器,分析了增程器产生转矩波动的原因.对比恒转矩控制,根据发动机做功的特点,提出了正转矩区控制和抵消负转矩区控制2种动态转矩控制策略.计算结果表明2种控制策略分别降低了17.89％和28.89％的平均转矩波动.证明了应用动态转矩控制能够降低增程器的转矩波...     

低碳背景下基于自适应鲁棒优化的含源配电系统规划方法

提出了一种低碳背景下基于自适应鲁棒优化的含源配电系统规划方法,该方法建立了考虑碳排放约束的近似混合整数线性模型,对电容器组和分布式可再生能源选址定容、过载线路的导线更换和电压调节器进行综合配置;考虑到负荷和分布式可再生能源输出功率的不确定性,采用了自适应鲁棒优化法将不确定模型重塑为3层问题;将3层模型重构为主、子问题双层模型,并采用列和约束生成算法求解该模型。算例采用135节点配电系统在不同情况下进行了研究,以评估所提方法的性能。结果表明,所提模型与方法有利于提高配电系统规划效率,并降低碳排放。     

Component sizing optimization of plug-in hybrid electric vehicles

Plug-in hybrid electric vehicles (PHEVs) are considered as one of the most promising means to improve the near-term sustainability of the transportation and stationary energy sectors. This paper describes a methodology for the optimization of PHEVs component sizing using parallel chaos optimization algorithm (PCOA). In this approach, the objective function is defined so as to minimize the drivetrain cost. In addition, the driving performance requirements are considered as constraints. Finally, the optimization process is performed over three different all electric range (AER) and two types of batteries. The results from computer simulation show the effectiveness of the approach and the reduction in drivetrian cost while ensuring the vehicle performance.     

Performance assessment of thermal management systems for electric and hybrid electric vehicles

Thermal management systems (TMS) are one of the key components of electric and hybrid electric vehicles to achieve high vehicle efficiency and performance under all operating conditions. Current improvements in electric battery technology allow vehicles to have relatively long ranges, fast acceleration, and long life while keeping low‐maintenance costs and considerably lower emissions. However, the vehicle performance is significantly affected by the battery operating conditions. Moreover, the cell life cycle, safety, and possibility of thermal runaway significantly depend on peak temperature rise and temperature uniformity of the battery. Therefore, various TMSs are created to keep batteries within ideal operating ranges. In this article, three different TMS systems—passive cabin cooling (via air), active moderate liquid circulation (via refrigerant), and active liquid circulation (via refrigerant and coolant)—are analyzed and compared with electric and hybrid electric vehicles. A second law analysis is used to examine the areas of low exergy efficiency in each system and minimize the entropy generation based on the system configuration. Moreover, TMS systems are compared on the basis of battery temperature increase and temperature uniformity. Various parametric studies are conducted to compare the TMS in different ambient and operating conditions. On the basis of the analysis, the active liquid circulation (via refrigerant and coolant) is determined to have the lowest battery temperature increase (3.9 °C in 30 min) and most cell temperature uniformity (2.5 °C median) as well as the lowest entropy generation rate (0.0121 W/K) among the compared systems. Copyright © 2012 John Wiley & Sons, Ltd.     

电动汽车参与受阻风电消纳的源荷优化控制方法

大规模的电动汽车负荷可增加电网系统的调峰能力,消纳受阻风电。文章首先根据系统负荷和风电出力特性分析其受阻原因;其次,通过对电动汽车充放电特性、可时移特性和SOC模型的分析,建立了电动汽车充放电模型,并提出相应策略;然后,以电动汽车消纳后的风电剩余受阻量最小为目标,建立电动汽车参与受阻风电消纳的源荷优化控制模型,并利用差分进化算法对模型进行求解;最后,以某地区电网实际数据进行仿真计算,验证电动汽车参与受阻风电消纳协调控制的可行性与有效性。     

High-energy electrode investigation for plug-in hybrid electric vehicles

In addition to the development of high-energy density electrode materials for lithium-ion (Li-ion) batteries, other engineering approaches, such as electrode optimization, should be considered in order to meet the energy requirements of plug-in hybrid electric vehicles (PHEV). This work investigates the impact of the electrode thickness on the energy density of (Li-ion) batteries. The impedance results from the hybrid pulse power characterization (HPPC) test indicate that the electrode resistance is inversely proportional to the electrode thickness. This feature makes it possible to use thicker electrodes in (Li-ion) batteries to meet PHEV power requirements. The practical electrode thickness is determined to be around 100 μm, if considering the electrode mechanical integrity when using conventional PVDF binders. Furthermore, cycle performance shows that cells with a higher loading density have a similar capacity retention to cells with a lower loading density.     

Investigation of battery end-of-life conditions for plug-in hybrid electric vehicles

Plug-in hybrid electric vehicles (PHEVs) capable of drawing tractive energy from the electric grid represent an energy efficient alternative to conventional vehicles. After several thousand charge depleting cycles, PHEV traction batteries can be subject to energy and power degradation which has the potential to affect vehicle performance and efficiency. This study seeks to understand the effect of battery degradation and the need for battery replacement in PHEVs through the experimental measurement of lithium ion battery lifetime under PHEV-type driving and charging conditions. The dynamic characteristics of the battery performance over its lifetime are then input into a vehicle performance and fuel consumption simulation to understand these effects as a function of battery degradation state, and as a function of vehicle control strategy. The results of this study show that active management of PHEV battery degradation by the vehicle control system can improve PHEV performance and fuel consumption relative to a more passive baseline. Simulation of the performance of the PHEV throughout its battery lifetime shows that battery replacement will be neither economically incentivized nor necessary to maintain performance in PHEVs. These results have important implications for techno-economic evaluations of PHEVs which have treated battery replacement and its costs with inconsistency.     

A cost comparison of fuel-cell and battery electric vehicles

This paper compares the manufacturing and refueling costs of a fuel-cell vehicle (FCV) and a battery electric vehicle (BEV) using an automobile model reflecting the largest segment of light-duty vehicles. We use results from widely-cited government studies to compare the manufacturing and refueling costs of a BEV and a FCV capable of delivering 135 hp and driving approximately 300 miles. Our results show that a BEV performs far more favorably in terms of cost, energy efficiency, weight, and volume. The differences are particularly dramatic when we assume that energy is derived from renewable resources.     

电动汽车的双向DC-DC变换器多模态控制方法

针对当前电动汽车功率控制过程中存在负载跳变抗干扰性能差、响应速度较慢等问题,提出一种应用于电动汽车的双向DC-DC变换器多模态控制方法。文章详细分析了电动汽车双向DC-DC变换器的拓扑结构和升降压控制模式;结合不同工况下的变换器工作状态,分析电压和电流模式控制,得出其电压、电流开闭环函数;利用多模态控制方法,由变换器的功能控制单元下达电压、电流环给定信号来实现功率波动平抑控制;在MATLAB中搭建了仿真模型。仿真结果表明,文章所提出的控制方法能够较好地实现双向DC-DC变换器的功率波动平抑功能,具有稳定性好、对负载跳变抗干扰性能强、响应速度快的特点。     

并联混合动力汽车能量管理与转矩协调控制策略

研究并联混合动力汽车的控制策略。基于发动机输出转矩最优的能量管理策略,对并联混合动力汽车在工作模式切换中的相互配合问题,提出发动机动态转矩控制+动力电池荷电状态(state of charge,SOC)干预+电机转矩补偿控制的转矩协调控制方法;在Matlab/Simulink/Stateflow平台搭建整车能量管理控制策略模型,控制发动机工作在高效率区,保证发动机输出最优转矩;根据电池的SOC干预电机的运行状态,协同发动机提供整车需求转矩。在Cruise平台下建立整车模型,以新欧洲驾驶周期作为循环工况进行离线仿真。结果表明,能量管理与转矩协调控制策略能够有效分配电机和发动机的转矩输出,满足混合动力汽车多模式切换的要求。     

II. A combined model for determining capacity usage and battery size for hybrid and plug-in hybrid electric vehicles

We combine a detailed battery model with a simple vehicle model to examine the battery size and capacity usage of a Li_xC₆/Li_y+0.16Mn_1.84O₄ cell (with a normal and artificially flat equilibrium potential) and a Li_4+3xTi₅O₁₂/Li_yFePO₄ cell. The features of cell chemistry we are concerned with are the magnitude and shape of the cell equilibrium potential and internal resistance. Our key findings include that a battery for a hybrid electric vehicle application has a capacity usage from 15 to 25% (for a minimum separator area size), and as one moves from a HEV battery to a plug-in hybrid electric vehicle battery there is a change in the slope of the separator area vs. equivalent-electric range curve due to the shape of the pulse-power capability. We also find that defining the resistance using the HPPC protocol has limitations because in general the pulse resistance depends on the applied current and pulse duration. Our detailed, combined model also shows that the benefits of a flat-potential system may be limited because of the relative positions of a flat and sloped equilibrium potential, and the lack of a driving force for the relaxation of solid-phase concentration gradients throughout the electrode. That latter effect is shown to be more significant for electrodes with a non-uniform current distribution.     

I. A simplified model for determining capacity usage and battery size for hybrid and plug-in hybrid electric vehicles

We develop a simplified model to examine the effect of the shape and magnitude of the battery pulse-power capability on capacity usage and battery size. The simplified model expresses the capacity usage and a dimensionless battery area in terms of a dimensionless energy-to-power ratio and a parameter that characterizes the shape of the pulse-power capability. We also present dimensional results that show how the capacity usage depends on the equivalent-electric range and separator area, and how the battery area depends on the equivalent-electric range. Key results include the presence of a Langmuir-like relationship between the capacity usage and the dimensionless energy-to-power ratio, and a linear relationship between the dimensionless energy-to-power ratio and a dimensionless area, with a slope and offset that depend on the shape of the pulse-power capability. We also found that a flat pulse-power capability curve increases capacity usage and decreases battery size, and that two important parameters for battery design are (U − V_min)V_min/R, which reflects the maximum power capability, and Q〈V〉, which reflects the battery energy. The results and analysis contained herein are used to help interpret the results from a combined battery and vehicle model, presented in a companion paper.