An optimal energy management development for various configuration of plug-in and hybrid electric vehicle

Due to soaring fuel prices and environmental concerns, hybrid electric vehicle(HEV) technology attracts more attentions in last decade. Energy management system, configuration of HEV and traffic conditions are the main factors which affect HEV's fuel consumption, emission and performance. Therefore, optimal management of the energy components is a key element for the success of a HEV. An optimal energy management system is developed for HEV based on genetic algorithm. Then, different powertrain system component combinations effects are investigated in various driving cycles. HEV simulation results are compared for default rule-based, fuzzy and GA-fuzzy controllers by using ADVISOR. The results indicate the effectiveness of proposed optimal controller over real world driving cycles. Also, an optimal powertrain configuration to improve fuel consumption and emission efficiency is proposed for each driving condition. Finally, the effects of batteries in initial state of charge and hybridization factor are investigated on HEV performance to evaluate fuel consumption and emissions. Fuel consumption average reduction of about 14% is obtained for optimal configuration data in contrast to default configuration. Also results indicate that proposed controller has reduced emission of about 10% in various traffic conditions.

A comparative study of hybrid electric vehicle fuel consumption over diverse driving cycles

Environmental pollution and declining resources of fossil fuels in recent years,have increased demand for better fuel economy and less pollution for ground transportation.Among the alternative solutions provided by researchers in recent decades,hybrid electric vehicles consisted of an internal combustion engine and an electric motor have been considered as a promising solution in the short-term.In the present study,fuel economy characteristics of a parallel hybrid electric vehicle are investigated by using numerical simulation.The simulation methodology is based on a fast forward facing simulation model of a parallel hybrid and an internal combustion engine powertrains.The objective of this study is to present the main parameters which result in an optimum combination of hybrid powertrain components in order to obtain a better fuel economy of hybrid powertrains regarding different driven cycles and hybridization factors.Then,the fuel consumption of the parallel hybrid electric vehicles are compared considering various driven cycles and hybridization factors.The results showed that the better fuel economy of hybrid powertrains increases by decreasing average load of the test cycle and the point of the best fuel economy for a particular average load of the cycle moves towards higher hybridization factors when the average load of the test cycle is reduced.

Multi-objective comprehensive optimization of fuel consumption and emission for hybrid electric vehicles

Aiming to reduce fuel consumption and emissions of a dual-clutch hybrid electric vehicle during cold start, multiobjective optimization for fuel consumption and HC/CO emission from a TWC(three-way catalytic converter) outlet is presented in this paper. DP(dynamic programming) considering dual-state variables is proposed based on the Bellman optimality principle. Both the battery SOC(state of charge) and the temperature of TWC monolith are considered in the algorithm simultaneously. In this way the global optimal control strategy and the Pareto optimal solution of multi-objective function are derived. Simulation results show that the proposed method is able to promote the TWC light-off significantly by decreasing the engine's load and improving exhaust temperature from the outlet of the engine, in comparison with original DP considering the single battery SOC. Compared to the results achieved by rule-based control strategy, fuel economy and emission of TWC outlet for cold start are optimized comprehensively. Each indicator of Pareto solution set shows the significant improvement.

A Novel Method for the Application of the ECMS(Equivalent Consumption Minimization Strategy)to Reduce Hydrogen Consumption in Fuel Cell Hybrid Electric Vehicles

Fuel cell hybrid electric vehicles are currently being considered as ideal means to solve the energy crisis and global warming in today’s society.In this context,this paper proposes a method to solve the problem related to the dependence of the so-called optimal equivalent factor(determined in the framework of the equivalent consumption minimum strategy-ECMS)on the working conditions.The simulation results show that under typical conditions(some representative cities being considered),the proposed strategy can maintain the power balance;for different initial battery’s states of charge(SOC),after the SOC stabilizes,the fuel consumption is 5.25 L/100 km.

Mathematical Model of Electric Vehicle Power Consumption for Traveling and Air-Conditioning

In order to make maximum use of the EV （electric vehicle） battery, evaluating the remaining battery capacity and the power consumption is important. Evaluation method of the remaining battery capacity with accuracy has been proposed. Moreover, the evaluation method of the power consumption for traveling has been proposed. However, the power consumption for vehicle-mounted air-conditioner is 30%. It is necessary to calculate the power consumption for both traveling and air-conditioning. In this paper, the authors have constructed a mathematical model which calculates the EV power consumption for both traveling and air-conditioning. The calculated results of this model have been compared to actual traveling data. In addition, factors which have a impact on the EV power consumption have been studied. As a result, the EV power consumption is greately varied by slope resistance, acceleration resistance and required air-conditioning load. Moreover, it is clarified that the air-conditioner consumes approximately 25% to 50% of the total power consumption in a hot summer day. In addition, the acceleration and the air-conditioning load differ depending on each vehicle driver. Therefore, in order to evaluate the EV power consumption practically, it is necessary to reflect the characteristics of each vehicle driver.

Experimental Study of Energy Consumption Variation in Recurring Driving Trips

With a growing consumer market of battery electric vehicles, customers＇ demand for technology and features is on the rise. The range and, to a certain extent, the range estimation will play a key factor in customers＇ purchase decisions. In order to guarantee a precise range estimation over the usage life of battery electric vehicles, a method is presented that combines adaptive filter algorithms with statistical approaches. The statistical approach uses recurring driving cycles over the lifetime in order to derive the aging status of the traction battery. It is implied that the variance of the energy usage of these driving cycles is within certain bounds. This fact should be proven by an experimental case study. The dataset used in this paper is open to the public.

A Predictive Energy Management Strategies for Mining Dump Trucks

The plug-in hybrid vehicles(PHEV)technology can effectively address the issues of poor dynamics and higher energy consumption commonly found in traditional mining dump trucks.Meanwhile,plug-in hybrid electric trucks can achieve excellent fuel economy through efficient energy management strategies(EMS).Therefore,a series hybrid system is constructed based on a 100-ton mining dump truck in this paper.And inspired by the dynamic programming(DP)algorithm,a predictive equivalent consumption minimization strategy(P-ECMS)based on the DP optimization result is proposed.Based on the optimal control manifold and the SOC reference trajectory obtained by the DP algorithm,the P-ECMS strategy performs real-time stage parameter optimization to obtain the optimal equivalent factor(EF).Finally,applying the equivalent consumption minimization strategy(ECMS)realizes real-time control.The simulation results show that the equivalent fuel consumption of the P-ECMS strategy under the experimentally collected mining cycle conditions is 150.8 L/100 km,which is 10.9%less than that of the common CDCS strategy(169.3 L/100 km),and achieves 99.47%of the fuel saving effect of the DP strategy(150 L/100 km).

Combined Prediction for Vehicle Speed with Fixed Route

Achieving accurate speed prediction provides the most critical support parameter for high-level energy management of plug-in hybrid electric vehicles.Nowadays,people often drive a vehicle on fixed routes in their daily travels and accurate speed predictions of these routes are possible with random prediction and machine learning,but the prediction accuracy still needs to be improved.The prediction accuracy of traditional prediction algorithms is difficult to further improve after reaching a certain accuracy;problems,such as over fitting,occur in the process of improving prediction accuracy.The combined prediction model proposed in this paper can abandon the transitional dependence on a single prediction.By combining the two prediction algorithms,the fusion of prediction performance is achieved,the limit of the single prediction performance is crossed,and the goal of improving vehicle speed prediction performance is achieved.In this paper,an extraction method suitable for fixed route vehicle speed is designed.The application of Markov and back propagation(BP)neural network in predictions is introduced.Three new combined prediction methods,all named Markov and BP Neural Network(MBNN)combined prediction algorithm,are proposed,which make full use of the advantages of Markov and BP neural network algorithms.Finally,the comparison among the prediction methods has been carried out.The results show that the three MBNN models have improved by about 19%,28%,and 29%compared with the Markov prediction model,which has better performance in the single prediction models.Overall,the MBNN combined prediction models can improve the prediction accuracy by 25.3%on average,which provides important support for the possible optimization of plug-in hybrid electric vehicle energy consumption.

Optimal Energy Management for a Complex Hybrid Electric Vehicle:Tolerating Power-loss of Motor

The energy management may perform well under normal conditions, but may lead to poor behavior under abnormal situations. To tackle this problem, an optimal control strategy called rule-based equivalent fuel consumption minimization strategy （RECMS） is developed for a new complex hybrid electric vehicle （CHEV）. It optimizes the energy efficiency and drive performance to cater for normal and power-loss operations of the tractive motor. Firstly, the strategy formulates a novel objective function based on the equivalent fuel concept. By accounting for the actual fuel cost, the equivalent fuel cost for the electric machines and virtual fuel cost for the drivability, the cost function is obtained. Furthermore, some penalty factors are presented to optimize the performance target. Finally, experiments for a practical CHEV are performed to validate a simulation model. Then simulations are carried out for both rule-based and RECMS. The results show that the optimal energy management is working well.

Robust Electric Vehicle Routing Problem with Time Windows under Demand Uncertainty and Weight-Related Energy Consumption

Vehicle routing problem with time windows(VRPTW)is a core combinatorial optimization problem in distribution tasks.The electric vehicle routing problem with time windows under demand uncertainty and weight-related energy consumption is an extension of the VRPTW.Although some researchers have studied either the electric VRPTW with nonlinear energy consumption model or the impact of the uncertain customer demand on the conventional vehicles,the literature on the integration of uncertain demand and energy consumption of electric vehicles is still scarce.However,practically,it is usually not feasible to ignore the uncertainty of customer demand and the weight-related energy consumption of electronic vehicles(EVs)in actual operation.Hence,we propose the robust optimization model based on a route-related uncertain set to tackle this problem.Moreover,adaptive large neighbourhood search heuristic has been developed to solve the problem due to the NP-hard nature of the problem.The effectiveness of the method is verified by experiments,and the influence of uncertain demand and uncertain parameters on the solution is further explored.

融合工况预测的燃料电池汽车里程自适应等效氢耗最小控制策略

为有效地提高插电式燃料电池汽车的经济性,实现燃料电池和动力电池的功率最优分配,考虑到行驶工况、电池荷电状态(State of charge,SOC)、等效因子与氢气消耗之间的密切联系,制定融合工况预测的里程自适应等效氢耗最小策略.通过基于误差反向传播的神经网络来实现未来短期车速的预测,分析未来车辆需求功率变化,同时借助全球定位系统规划一条通往目的地的路径,智能交通系统便可获取整个行程的交通流量信息,利用行驶里程和SOC实时动态修正等效消耗最小策略中的等效因子,实现能量管理策略的自适应性.基于MATLAB/Simulink软件,搭建整车仿真模型与传统的能量管理策略进行仿真对比验证.仿真结果表明,采用基于神经网络的工况预测算法能够较好地预测未来短期工况,其预测精度相较于马尔可夫方法提高12.5%,所提出的能量管理策略在城市道路循环工况(UDDS)下的氢气消耗比电量消耗维持(CD/CS)策略下降55.6%.硬件在环试验表明,在市郊循环工况(EUDC)下的氢气消耗比CD/CS策略下降26.8%,仿真验证结果表明了所提出的策略相比于CD/CS策略在氢气消耗方面的优越性能,并通过硬件在环实验验证了所提策略的有效性.

某纯电驱动重载车辆能耗预测模型

高精度能耗预测模型是准确预测车辆续驶里程的重要前提。针对载荷大幅度变化且非结构化道路运行的纯电驱动重载车辆,建立其组合能耗模型,该模型由能耗计算基本模型与长短时记忆(Long Short-Term Memory,LSTM)神经网络差值修正两部分组成。基于能量流动过程驱动电机和变速器效率建模,结合汽车行驶动力学建立能耗计算基本模型;采用LSTM神经网络来修正基本模型能耗预测结果与车辆典型工况功率测试值的差值,有效提高了大幅变载荷且低信噪比坡度环境下的车辆能耗预测精度,因此组合能耗模型具有参数简单和模型拟合不需解释能耗规律的优点。经试验测试分析,与VT-Micro能耗模型和径向基(Radial Basis Function,RBF)神经网络能耗模型相比,所提组合能耗模型的功率预测平均误差率分别降低了17.76%和3.35%,能够实现纯电驱动重载车辆复杂工况下能耗的准确实时预测。

考虑驾驶风格的混合动力汽车强化学习能量管理策略

为了提升混合动力汽车能量管理策略对不同风格驾驶员的适应性,基于深度强化学习和等效燃油消耗最小策略(equivalent consumption minimization strategy,ECMS),提出一种考虑驾驶风格的混合动力汽车能量管理策略。通过实车试验采集驾驶员行驶数据,基于采集数据进行驾驶员驾驶风格的聚类分析,建立驾驶风格识别模型;构建基于强化学习和ECMS的能量管理策略,将驾驶风格系数作为强化学习状态变量,利用多种驾驶风格的组合工况训练深度确定性策略梯度智能体,获取不同工况和驾驶风格下ECMS等效因子,采用ECMS求解最优发动机、电机转矩分配以及变速箱挡位;搭建硬件在环测试平台,并基于实际采集的不同驾驶员驾驶数据构建测试工况,验证所提出控制策略的有效性。研究结果表明,相较于基于规则策略、基于等效因子比例修正的自适应ECMS以及DRL-SAC策略,提出的考虑驾驶风格的强化学习能量管理策略使整车能量消耗分别降低16.35%、11.11%和7.56%,所提控制策略的有效性得到了验证。

基于充电行为电量规划的自适应能量管理策略

为提高插电式混合动力汽车(PHEV)的燃油经济性,以并联式PHEV为研究对象,考虑驾驶员充电行为,提出基于充电行为电量规划和等效燃油消耗最小策略(ECMS)的自适应能量管理策略。构建了包含不同类型工况的组合工况。根据驾驶员的充电行为特征(充电频率、充电上限、放电下限)进行充电行为分析,并进行4类工况电量消耗与燃油消耗ECMS策略下的离线仿真数据获取。根据驾驶员充电行为以及离线数据进行SOC轨迹的规划。结果表明:在电池SOC初始值分别为0.9、0.6时,提出的能量管理策略相较于基于电量消耗维持的等效燃油消耗策略,整车燃油经济性分别提升7.87%和13.1%。

电动汽车制动能量循环回收智能控制仿真

为提高纯电动汽车的续航能力,保证车辆稳定行驶,提出一种纯电动车辆的制动能量回收控制方法。从多个角度分析纯电动汽车在行驶过程中的能量变动情况,考虑驱动力需要克服的相关阻力,根据车辆各部件的工作效率以及电池充电情况,计算车辆驱动消耗实际电量。分析纯电动汽车制动过程中的动力学以及路面的摩擦因子对制动产生的影响,明确汽车制动时产生的能量损失和影响能量回收的相关因素。为了获得最大的再生能量,在能量回收控制中,以制动的方式进行能量补偿,并将更多的动能用于动力发电机,达到制动能量的回收循环。仿真结果表明,所研究方法对制动能量的回收控制效果较好,回收利用率较为理想。

动态负载下电动汽车配送路径优化

企业为响应国家“双碳”目标和降低配送费用,在货物配送中选择可代替传统燃油汽车的电动汽车已成为主流。针对电动汽车配送路径优化展开研究,分析了动态负载下电动汽车电量的非线性能量消耗,在已有非线性能量消耗模型的基础上,进一步探究电动汽车充电上游的碳排放,考虑配送过程中的路径、载重、电量及时间窗约束,建立以电动汽车固定成本、行驶成本、充电成本、时间窗惩罚成本和碳排放成本之和最小化为目标函数的路径优化模型。在蚁群算法的基础上,加入精英策略改进,通过实例求解得到最小配送成本及配送路线,验证了模型和改进算法的有效性。

基于蚁群算法的纯电动汽车路径规划研究

为了缓解纯电动汽车用户出行焦虑,提出一种考虑交通动态性及速度时变性的路径规划方法。根据道路节点位置、海拔高度、充电桩位置等信息建立沈阳市20 km×20 km区域道路拓扑结构,基于车辆充电需求、行驶距离、行驶时间、行驶能耗、附件能耗建立纯电动汽车多目标路径函数,采用蚁群算法开展路径规划。仿真结果表明,本文提出的规划方法能够找到切合实际的目标路径。

基于规划路径能耗预测的PHEV全局自适应能量管理

新能源汽车智能化能量管理是先进汽车技术研究的重要领域,是进一步提升整车燃油经济性能的关键。针对插电式混合动力汽车(Plug-in hybrid electric vehicle,PHEV)能量全局化管理与控制的实时性和最优性难以兼顾的难题,开展了基于能耗预测的全路径自适应能量管理研究,提出了以等效燃油消耗最小化为目标的全规划路径PHEV自适应控制算法。最后,基于MATLAB/Simulink的建模与仿真分析验证了所提控制算法对实际行驶工况、里程和整车能量状态的变化具有较好的跟随性和自适应性,全路径近似全局性优化控制效果明显,较好地改善了整车的燃油经济性。

纯电动汽车经济性驾驶的影响因素及应用

我国新能源汽车技术路线是以纯电驱动为主,随着纯电动汽车保有量的增加,降低其行驶能耗既符合国家节能减排的战略,又能改善用户的用车体验。基于某纯电动SUV车型的实际道路驾驶数据,通过相关性和降维分析得到加速度的方差是影响能耗的最关键因素;进而采用一维模型仿真,研究匀速、加减速和坡道3种典型工况下能耗的形成机理和优化方向,得到平衡能耗与行驶时长的经济性驾驶原则,如高速巡航时应适当降低车速,市区拥堵时控制加速度变化幅度,上下坡时利用车辆惯性,减少制动能量回收。

考虑分区域动态电价机制引导的电动汽车充电优化策略

为应对大规模电动汽车无序充电引起的配电网运行损耗增加问题,提出一种分区域动态电价机制引导的电动汽车(electric vehicle,EV)充电优化策略。该动态电价机制是根据不同区域内的负荷特点建立不同的动态电价,从而优化对应区域的EV充电。其中商业区建立计及充电站充电总功率的动态电价模型,居民区和办公区采用计及风光出力的动态电价模型。同时,提出充电效益系数模型以提升在居民区和办公区用户的充电时间满意度。最后,在IEEE33节点系统上进行仿真验证。结果表明,所提出的基于分区域动态电价机制的EV充电优化策略能够在保证车主利益的同时,降低网损、提高配网电压质量、促进风光消纳以及提升配网的经济性。