Energy and environmental life-cycle assessment of passenger car electrification based on Beijing driving patterns

This paper examines the energy and environmental benefits within the whole life cycle shifting from traditional gasoline vehicles to electrified advanced vehicles under regional real-world driving behaviors.The advance vehicles focus on family passenger cars and include battery electric vehicles(BEVs),plug-in hybrid electric vehicles(PHEVs),and hybrid electric vehicles(HEVs).The GREET(greenhouse gases,regulated emissions,and energy use in transportation)model is adopted with regional circumstances modifications,especially the UF(utility factors)of PHEVs.The results show that the electrified vehicles offer great benefits concerning energy consumption,greenhouse gas(GHG)emissions as well as urban Particulate Matter 2.5(PM2.5)emissions.Compared to conventional gasoline vehicles,the life-cycle total energy reduction for advance vehicles is 51%to57%.There is little difference on energy reduction among the HEVs,PHEVs and BEVs,with the energy mix shifting from petroleum to coal for the stronger electrification.The reductions of GHG emissions are 57%for HEV,54%to 48%for PHEVs with 10 miles to 40 miles CD range,and 40%for BEV.The life-cycle and local PM2.5 emissions are discussed separately.The life-cycle PM2.5 emissions increase with vehicle electrification and reach a maximum for the BEV which are 5%higher than the conventional vehicle(CV).However,electric vehicles can shift PM2.5 emissions from vehicle operation to upstream operations and help mitigate PM2.5 emissions in urban areas.The local emissions of PHEVs and BEVs can be reduced by 37%to81%and 100%compared with CVs.     

Future penetration and impacts of electric vehicles on transport energy consumption and CO<Subscript>2</Subscript> emissions in different Chinese tiered cities

This study focuses on the penetration of electric vehicles (EVs) within the private passenger vehicle market in selected Chinese cities categorized into different tiers. It presents an analysis of factors driving the market diffusion of EVs and the reasons for varying results across the investigated cities and provides estimates of related EV impacts on local energy consumption and CO₂ emissions. A nested multinomial model incorporating technological attributes of vehicles, energy prices, charging conditions, and incentive policies was developed for conducting a scenario analyses covering six cities. The results indicated that in a stagnation scenario in which policy support was absent, the market share of electric vehicles would be less than 7% in all six cities under investigation by 2030. In medium growth and rapid growth scenarios, the market share of EVs across the six cities was projected to be within the ranges of 29%–68% and 49%–80%, respectively. The impacts of EVs on gasoline demand depended not just on their cumulative sales but also on the share of electrified vehicle distance, and the CO₂ emission reduction effect was influenced by local EV stocks and the mix of local electricity sources. Battery costs, charging conditions, and energy prices were primary driving factors. Charging conditions and energy prices were key reasons for differences in the penetration curves among cities. These driving factors were further affected by differences in local income levels, housing and parking conditions, and availability of land resources. Subsidies were found to be effective in the short term, whereas in the medium term, tax breaks could serve as the main monetary incentive. In the long term, national policy should focus on technology-related R&D, whereas local policies should focus on the operational phase and be tailored to specific local situations.     

电动汽车电池管理系统和剩余容量计研究

目的研究和开发电动汽车电池管理系统,实现铅酸储能蓄电池的剩余容量计量技术。方法通过对电动汽车铅酸储能电池基本电化学特性分析,采用了以安时法－Ｐｅｕｋｅｒｔ公式－开路电压法为基本算法,进行电池管理系统的开发,同时考虑了温度、自放电、使用循环寿命等因素对铅酸电池剩余容量预测的影响。结果所开发的管理系统铅酸电池剩余容量静态充放电实验计量误差小于５％,提供给驾驶员一个较准确的剩余容量,并对电池组中每声池进行监测,对铅酸电池的过放电和过充电等非正常工作情况及时报警,实用性强。结论电动汽车电池管理系统可以有效延长电池的使用寿命,优化电池能量的利用,提高电动汽车的性能。     

基于Radau伪谱法和MPC的智能电动车辆生态驾驶

为优化智能电动车能源消耗,提出了基于Radau伪谱法和模型预测控制算法的智能电动车辆生态驾驶的方案。建立生态驾驶控制模型和能耗模型,结合边界约束和路径约束,构建生态驾驶能耗优化的最优控制问题。通过能耗优化得到最优车速轨迹,将此轨迹作为期望输入,基于模型预测控制( MPC)算法完成生态驾驶控制。实验结果表明：以纯电动车和实际规划路径为例,以最优车速自动行驶的能源消耗少于人工驾驶的能源消耗,验证了文中策略的有效性。     

圆柱18650锂离子动力电池放电及温度特性

能耗和环境问题促使电动汽车快速发展, 锂离子电池在电动汽车储能系统中具有重要的作用. 锂离子动力电池的特性与环境温度紧密相关, 倍率放电容量特性、荷电状态-开路电压曲线是反映电池基本性能的重要特性指标, 也是电池管理系统设计需要参考的重要参数. 该文对圆柱18650三元锂离子动力电池进行了相关的性能试验, 研究了单体和电池组开路电压变化规律、不同放电倍率下的电池容量和不同温度下的电池容量, 为荷电状态估算方法的研究及电池管理系统设计积累了数据.     

混合动力汽车经济型巡航的车速规划策略

选取功率分流式混合动力汽车为对象,以燃油消耗最小为目标开展巡航场景下的经济车速规划研究. 结合车辆动能管理与等效燃油最小化策略（ECMS）,提出增强型等效燃油最小化策略（R-ECMS）. 运用极小值原理推导油电等效系数,建立动能与电能间的等效关系;结合电能与燃油之间的等效关系,将车辆动能变化和电能消耗统一转化成燃油消耗. 为了兼顾电池SOC平衡以及车辆通行速度,采取非支配排序遗传算法优化R-ECMS权重系数中的参数. 仿真结果表明,与传统能量管理策略ECMS相比,R-ECMS可以降低8.06%的燃油消耗. 与采用最优算法的动态规划策略相比,R-ECMS能在实现次优的优化效果的同时大幅降低计算时间. 同时,与ECMS相比,R-ECMS在其他仿真场景下能实现6.94%的节油率,具有较好的泛化性能和应用前景.     

Real-time optimization power-split strategy for hybrid electric vehicles

Energy management strategies based on optimal control theory can achieve minimum fuel consumption for hybrid electric vehicles, but the requirement for driving cycles known in prior leads to a real-time problem. A real-time optimization power-split strategy is proposed based on linear quadratic optimal control. The battery state of charge sustainability and fuel economy are ensured by designing a quadratic performance index combined with two rules. The engine power and motor power of this strategy are calculated in real-time based on current system state and command, and not related to future driving conditions. The simulation results in ADVISOR demonstrate that, under the conditions of various driving cycles, road slopes and vehicle parameters, the proposed strategy significantly improves fuel economy, which is very close to that of the optimal control based on Pontryagin’s minimum principle, and greatly reduces computation complexity.     

电动汽车充放电模式对电网日负荷的影响

根据传统汽车的行驶特性,分析各类电动汽车充电行为的影响因素,考虑在3种充放电模式下电动汽车的充放电方式、电池特性、充放电时间及充电成本等因素,建立基于蒙特卡罗模拟法的规模化电动汽车在不同充放电模式下的日负荷模型. 分析结果表明,电动汽车无序充电会导致电网峰谷差率增加,单向有序充电则可在一定程度上实现“填谷”目标,而双向有序充放电模式下的电动汽车负荷可以更好地平抑电网负荷波动,缓解电力紧张,并给用户带来一定的经济收益.     

Challenges and recent progress in thermal management with heat pipes for lithium-ion power batteries in electric vehicles

Electric vehicles(EVs) are globally undergoing rapid developments, and have great potentials to replace the traditional vehicles based on fossil fuels. Power-type lithium-ion batteries(LIBs) have been widely used for EVs, owing to high power densities,good charge/discharge stability, and long cycle life. The driving ranges and acceleration performances are gaining increasing concerns from customers, which depend highly on the power level of LIBs. With the increase in power outputs, rising heat generation significantly affects the battery performances, and in particular operation safety. Meanwhile, the cold-start performance is still an intractable problem under extreme conditions. These challenges put forward higher requirements for a dedicated battery thermal management system(BTMS). Compared to traditional BTMSs in EVs, the heat pipe-based BTMS has great application prospects owing to its compact structure, flexibility, low cost, and especially high thermal conductivity. Encompassing this topic, this review first introduces heat generation phenomena and temperature characteristics of LIBs. Multiple abuse conditions and thermal runaway issues are described afterward. Typical cooling and preheating methods for designing a BTMS are also discussed. More emphasis on this review is put on the use of various heat pipes for BTMSs to enhance the thermal performances of LIBs. For lack of wide application in actual EVs, more efforts should be made to extend the use of heat pipes for constructing an energy-efficient, cost-effective, and reliable BTMS to improve the performances and safety of EVs.     

Energy cost minimization through optimization of EV,home and workplace battery storage

Besides grid-to-vehicle (G2V) and vehicle-to-grid (V2G) functions, the battery of an electric vehicle (EV) also has the specific feature of mobility. This means that EVs not only have the potential to utilize the storage of cheap electricity for use in high energy price periods, but can also transfer energy from one place to another place. Based on these special features of an EV battery, a new EV energy scheduling method has been developed and is described in this article. The approach is aimed at optimizing the utilization EV energy for EVs that are regularly used in multiple places. The objective is to minimize electricity costs from multiple meter points. This work applies real data in order to analyze the effectiveness of the method. The results show that by applying the control strategy presented in this paper at locations where the EVs are parked, the electricity cost can be reduced without shifting the demand and lowering customer’s satisfaction. The effects of PV size and number of EVs on our model are also analyzed in this paper. This model has the potential to be used by energy system designers as a new perspective to determine optimal sizes of generators or storage devices in energy systems.     

电动车无线能量互充系统及其恒流控制

针对电动车行驶途中可能出现电量不足的突发情况,提出了一种新的能量互充系统,用有富余电量的私人车辆或者专门提供能量补给服务的车辆为缺电车辆提供应急性能量补给。给出一种结构对称和参数对称的主电路拓扑,并引入移相控制策略来实现恒流充电。建立了系统的等效电路模型,推导出了发射端逆变器移相角与充电电流、发射线圈与拾取线圈距离之间的函数关系式。仿真和实验结果均验证了该系统及控制策略的可行性。     

起动电压对电控柴油机起动性能的影响

应用德国BOSCH公司生产的VP37电控分配泵管理系统与大连柴油机厂生产的CA498Z型柴油机所组成的电控CA498Z型柴油机以及与该管理系统相匹配的VS100标定系统,试验研究了起动电压对电控柴油机起动性能的影响。结果表明:对试验用柴油机存在一最佳的最低起动转速,此时消耗的蓄电池能量最少,又能保证顺利起动。     

考虑环境温度的电动汽车充电负荷预测

为了保证电动汽车充电负荷预测更加准确、合理,分析环境温度导致电池特性、空调能耗和道路状况的变化对电动汽车充电需求的影响。考虑环境温度因素,引入能耗因子计算单位里程耗电量,利用蒙特卡洛法计算单辆车的充电负荷需求,再累加到总的充电负荷曲线上。以2020年上海市电动汽车为例仿真计算,验证了在不同温度影响下,电动汽车充电负荷会发生明显的变化。     

考虑环境温度的电动汽车充电负荷预测

为了保证电动汽车充电负荷预测更加准确、合理,分析了环境温度导致电池特性、空调能耗和道路状况的变化对电动汽车充电需求的影响.考虑环境温度因素,引入能耗因子计算单位里程耗电量,利用蒙特卡洛法计算了单辆车的充电负荷需求,再累加到总的充电负荷曲线上.以2020年上海市电动汽车为例仿真计算,验证了在不同温度影响下,电动汽车充电负荷会发生明显的变化.     

前后轴独立驱动的增程式电动汽车整车控制策略

纯电动汽车因续驶里程短和充电速度慢等原因制约了其进一步发展,增程式电动汽车在保证较低燃油消耗率的前提下弥补了纯电动汽车的缺陷。本文以前后轴独立驱动的增程式电动汽车为例,以保证整车的动力性能和降低燃油消耗率为出发点,提出了前后轴独立驱动增程式电动汽车的整车逻辑门限控制策略,该策略控制发动机的工作点随整车需求功率的变化而工作在不同的最优燃油消耗点上。仿真分析可知发动机在不同工况下均可以工作在低燃油消耗点附近,这表明该控制策略可实现对整车燃油经济性的良好控制。     

Optimum control strategy for all-variable speed chiller plant

The optimum control strategy and the saving potential of all variable chiller plant under the conditions of changing building cooling load and cooling water supply temperature were investigated. Based on a simulation model of water source chiller plant established in dynamic transient simulation program (TRNSYS), the four-variable quadratic orthogonal regression experiments were carried out by taking cooling load, cooling water supply temperature, cooling water flow rate and chilled water flow rate as variables, and the fitting formulas expressing the relationships between the total energy consumption of chiller plant with the four selected parameters was obtained. With the SAS statistical software and MATHEMATICA mathematical software, the optimal chilled water flow rate and cooling water flow rate which result in the minimum total energy consumption were determined under continuously varying cooling load and cooling water supply temperature. With regard to a chiller plant serving an office building in Shanghai, the total energy consumptions under different control strategies were computed in terms of the forecasting function of cooling load and water source temperature. The results show that applying the optimal control strategy to the chiller plant can bring a saving of 23.27% in power compared with the corresponding conventional variable speed plant, indicating that the optimal control strategy can improve the energy efficiency of chiller plant.     

系统效率最优的功率分流式混合动力汽车非线性预测控制

针对一种基于双行星排构型的功率分流式混合动力汽车,建立系统动态模型,准确描述其转速转矩耦合关系,通过建立各部件的效率模型,分析不同模式下系统的工作效率. 设计控制器结构框架,以系统工作效率和电池充放电平衡为目标,构建基于模型预测控制的优化问题,采用一步马尔科夫链模型预测驾驶员需求转矩及车速,将有限时域内的优化问题转化为非线性规划问题,基于序列二次规划算法实现优化求解. 仿真研究表明,基于系统效率最优的预测控制器能够维持电池的充放电平衡,在美国城市驾驶循环（UDDS）下,当电池初始电池荷电状态（SOC）分别为0.50、0.55和0.60时,相较于以发动机燃油消耗最优为目标,车辆等效燃油经济性分别提高了7.17%、5.73%和10.11%,验证了控制器的有效性和优越性.     

Cloud Computing Based Optimal Driving for a Parallel Hybrid Electric Vehicle

A cloud computing based optimal driving method is proposed and its feasibility is validated through a real-world scenario simulation. Based on principles of vehicle dynamics, the driving optimization problem has been formulated into an optimal control problem constrained by traffic rules, directed at achieving lower equivalent fuel consumption and shorter travel time. In order to conveniently specify the constraints and facilitate the application of the dynamic programming (DP) algorithm, the driving optimization problem is transformed into spatial domain and discretized properly. Considering the heavy computational costs of the DP algorithm, a cloud computing based platform structure is proposed to solve the optimal driving problem in real-time. A case study is simulated based on a real-world traffic scenario in Matlab. Simulation results demonstrate that the cloud computing framework is promising toward realizing the real-time energy management for hybrid electric vehicles.     

Design and optimization of equivalent consumption minimization strategy for 4WD hybrid electric vehicles incorporating vehicle connectivity

This paper presents an optimized equivalent consumption minimization strategy(ECMS) for four-wheel-drive(4 WD) hybrid electric vehicles(HEVs) incorporating vehicle connectivity. In order to be applicable to the 4 WD architecture, the ECMS is designed based on a rule-based strategy and used under the condition that a certain propulsion mode is activated. Assuming that a group of 4 WD HEVs are connected and position information can be shared with each other, we formulate a decentralized model predictive control(MPC) framework that compromises fuel efficiency, mobility, and inter-vehicle distance to optimize the velocity profile of each individual vehicle. Based on the optimized velocity profile, an optimization problem considering both fuel economy and battery state of charge(SOC) sustainability is formulated to optimize the equivalent factors(EFs) of the ECMS for HEVs over an appropriate time window. MATLAB User Datagram Protocol(UDP) is used in the codes run on multiple computers to simulate the wireless communication among vehicles, which share position information via UDP-based communication, and dSPACE is used as a software-in-the-loop platform for the simulation of the optimized ECMS. Simulation results validate the control effectiveness of the proposed method.     

四轮独立驱动电动汽车动力学控制系统仿真

论述了四轮独立驱动系统作为汽车驱动系统的优势及在电动汽车上应用的技术潜力。比较了ICEV动力学控制系统与EV动力学控制系统的区别,提出了四轮独立驱动电动汽车的新动力学控制方法。该方法利用前轮转向角和车速的前馈控制与基于质心侧偏角和横摆角速度的误差反馈控制相结合来控制车辆运动状态,并通过最优控制的方法确定了反馈系数。建立了整车数学模型,并利用MATLAB/Simulink软件生成系统的仿真模型,对所述控制系统进行了仿真研究。结果表明:前馈与反馈相结合的控制系统在各种路面条件下均可明显改善汽车的动力学性能。