Chaos oscillator differential search combined with Pontryagin’s minimum principle for simultaneous power management and component sizing of PHEVs

Over the past decade, plug-in hybrid electric vehicles (PHEVs) have found a good reputation in the automotive industry due to the fact that they neatly satisfy the existing tight environmental regulations and fuel economy requirements. Recently, there has been more interest in the design optimization of the PHEV powertrains to improve their operational characteristics to the maximum possible extent. The PHEV powertrains are complicated systems and include different controllers and components which should operate corporately to guarantee the acceptable performance of the vehicle. The reported investigations indicate that improving the performance of PHEVs is a very arduous task because both control strategies and component sizes should be optimized in tandem; however, in most of the previous studies, the focus has been on improving one of the above-mentioned aspects, which does not result in the most efficient design. The main goal of the current study is to take advantage of a bi-level optimization framework which combines the optimizations of both powertrain component sizes and power management controller for a specific PHEV, namely 2012 Toyota plug-in Prius. The bi-level optimizer comprises a chaos-enhanced differential evolutionary algorithm, which is in charge of the component sizing, and a classical optimal control approach based on the Pontryagin’s minimum principle, which optimizes the vehicle power management strategy. A high-fidelity model of the vehicle is developed in the Autonomie software. This high-fidelity model is used to identify the parameters of a reduced model representing the vehicle dynamics by means of the homotopy analysis method, and the resulting model is then employed for the optimization procedure. The results of the numerical experiments indicate that by considering both component sizing and control strategy optimization, a very powerful tool is developed which can significantly improve the total fuel cost (F _C ), acceleration time (T _acc ), and battery state of charge (SOC) trajectory of the vehicle.     

Multi-objective component sizing of plug-in hybrid electric vehicle for optimal energy management

This paper presents a methodology for component sizing optimization of a parallel plug-in hybrid electric vehicle by considering it as a multi-objective optimization problem. In this approach, two objective functions are defined to minimize the drivetrain cost, fuel consumption, and exhaust emissions simultaneously. Also, the driving performance requirements are considered as constraints. In addition, fuzzy logic controller including blended control strategy is developed for the PHEV. Finally, by means of multi-objective particle swarm optimization algorithm, the best choices of components are selected for 32 miles of the both TEH-CAR and UDDS driving cycles. Simulation results demonstrate the effectiveness and practicality of the approach, which prepare different optimal component sizes with various drivetrain costs, equivalent fuel consumption, and exhaust emissions.     

基于遗传算法的混合动力汽车动力总成悬置系统的优化设计研究

为了提高并联式混合动力汽车动力总成五点悬置系统的隔振性能,建立了动力总成五点悬置的动力学模型,以动力总成六自由度能量解耦与固有频率的合理分配为优化目标,五个悬置点的各向刚度为设计变量,采用遗传算法对悬置系统进行优化。应用上述方法对某并联式柴电混合动力汽车悬置系统进行了优化,动力学仿真与实车试验结果表明,悬置优化后消除了整车怠速工况时方向盘抖动,验证了所提方法的合理性。同时,遗传算法克服了序列二次型规划算法（SQP）易收敛于局部最优解的缺点,得到的悬置系统解耦性能优良,优化结果稳定可靠。     

纯电动客车振动试验分析及动力总成隔振优化

汽车电动化使动力总成的振动噪声特性发生很大变化,带来了新的NVH问题,作为短途客运主要运输工具的纯电动客车尤为明显。针对某纯电动客车在行驶中存在振动较大的问题,结合实车试验与理论仿真,研究其振动传递特性及隔振优化。首先,基于LMS Test.lab振动噪声测试平台,采集了车内地板与底盘关键点的振动信号进行振动试验分析,根据车内地板振动响应特性对18条振动传递路径进行振动贡献量分析,求解出各个传递路径对车内目标点振动的贡献量,确定振动的主要贡献路径。其次,根据传递路径分析结果,针对主要贡献路径上的减振关键环节(动力总成悬置)进行隔振性能分析,结果显示电机动力总成悬置系统较差的隔振性能是引起车内振动过大的主要原因。为此,进一步建立了六自由度动力总成优化模型,采用多岛遗传优化方法对悬置系统参数进行优化匹配设计。结果表明,悬置系统的隔振性能获得了显著提升,车内振动过大问题得到有效解决。     

Calibration and optimization of an electric vehicle powertrain system

ABSTRACT

The problem of insufficient driving performance in existing electric vehicle (EV) powertrain systems is solved in this paper by presenting the EV as the reference object. The system model of the EV is established based on the powertrain system layout, technical parameters, and performance requirements, and the vehicle dynamic property and pure electric drive economy are evaluated. On the basis of the component models and total outputted power, the driving range is considered as the optimization target, and the input simulation parameters are considered as the optimized variables. Therefore, the optimal variable parameters are determined by multiple simulation analysis. In view of the test bench results, the rationality of the parameters of the simulation result is verified. Generally speaking, with the flexible configuration of the designed powertrain system and the optimized parameters of dynamic programming, the automobile performance can be improved.     

Technical Characteristics Analysis for Toyota Prius Hybrid Vehicle

In order to solve the problem effectively that increasing car ownership relies on limited resources like oil and the resulting environmental pollution because of vehicle exhaust,"New energy vehicles"is not a new conception which is mentioned frequently and has been used in practical applications in our daily life. As a typical representative of the use of new energy vehicles,Prius,a kind of gas-electric hybrid cars which are made by Toyota is a very typical type in technique and application. Using Prius as an example,we will focus on its chemical reaction principle of electrical energy storage device and evaluation parameters,the structure of driving motors and gives the dqmodel of the electrical machine in dqcoordinates,the structure of dynamic coupling device,convertor assembly which including four kinds of convertor and its function,finally,introducing the working principles and characteristics of the system assembly in this paper.     

Design optimization and optimal control for hybrid vehicles

In the context of growing environmental concerns, hybrid-electric vehicles appear to be one of the most promising technologies for reducing fuel consumption and pollutant emissions. This paper presents a parametric study focused on variations of the size of the powertrain components, and optimization of the power split between the engine and electric motor with respect to fuel consumption. To take into account the ability of the engine to be turned off, and the energy consumed to start the engine, we consider a second state to represent the engine: this state permits to obtain a more realistic engine model than it is usually done. Results are obtained for a prescribed vehicle cycle thanks to a dynamic programming algorithm based on a reduced model, and furnish the optimal power repartition at each time step regarding fuel consumption under constraints on the battery state of charge, and may then be used to determine the best components of a given powertrain. To control the energy sources in real driving conditions, when the future is unknown, a real-time control strategy is used: the Equivalent Consumption Minimization Strategy (ECMS). In this strategy, the battery is being considered as an auxiliary reversible fuel reservoir, using a scaling parameter which can be deduced from dynamic programming results. Offline optimization results and ECMS are compared for a realistic hybrid vehicle application.     

液压挖掘机动力总成悬置系统隔振性能分析与优化

以某型国产液压挖掘机为研究对象,建立动力总成悬置系统数学模型与Adams动力学模型,仿真分析结果表明系统存在严重的耦合现象,隔振性能不理想。利用Isight软件集成Matlab,以悬置刚度参数作为设计变量,悬置系统能量解耦率为目标函数,以固有频率合理分配为约束条件,建立优化模型并开展灵敏度分析与优化分析,优化后系统解耦程度得到明显改善,优化方案对液压挖掘机动力总成悬置系统实车优化具有一定参考价值。     

HEV动力总成硬件在环仿真系统的研究与开发

硬件在环仿真技术是现代控制系统设计中先进的技术手段。结合混合动力汽车(HEV)动力总成控制单元(PCU)的开发要求，分别从硬件在环仿真系统(HILSS)的硬件和软件两个方面对HEV动力总成HILSS进行了设计开发工作。开发的HILSS应用于HEV动力总成控制单元的设计开发和功能测试，提高了系统的设计效率和设计水平。     

并联式混合动力汽车多能源动力总成控制单元的研究与开发

根据并联式混合动力系统结构，研究了其运行模式以及动力源能量分配的控制策略。研究了配置自动机械式变速器的换档要求，提出了控制系统切实可行的换档控制方案。设计开发了动力总成控制单元。并利用自主开发的硬件在环仿真系统对其进行了测试和验证。测试结果表明，开发的控制器满足设计要求，为进一步的台架试验工作奠定了基础。     

Parametric Optimization of Hybrid Car Engines

We consider the problem of optimal design of hybrid car engines which combine thermal and electric power. The optimal configuration of the different motors composing the hybrid system involves the choice of certain design parameters. For a given configuration, the goal is to minimize the fuel consumption along a trajectory. This is an optimal control problem with one state variable.The simultaneous optimization of design parameters and trajectories can be formulated as a bilevel optimization problem. The lower level computes the optimal control for a given architecture. The higher level seeks for the optimal design parameters by solving a nonconvex nonsmooth optimization problem with a bundle method.     

密封舱控制力矩陀螺振动噪声控制分析与验证

控制力矩陀螺（CMG）是航天器姿态控制的执行器，内含高速转子，是航天器上重要的振动及噪声源。对某舱外安装CMG的载人航天器密封舱开展噪声测试，发现噪声总声级过大且主要为与CMG工频及2 倍频对应的单频噪声。对CMG进行隔振处理并对隔振系统特性进行分析，发现隔振措施使工频扰振力输出显著减小，但在2 倍频处隔振效果弱于工频处，其原因在于受到CMG弹性的影响。载人密封舱振动噪声耦合分析表明隔振措施使密封舱薄壁振动的幅值及范围大幅减小，从而降低密封舱噪声。在安装隔振器的载人密封舱进行验证试验，隔振系统固有频率实测值与仿真结果吻合较好，CMG工频处噪声降幅达18 dB～21 dB，2 倍频噪声降幅达2 dB～7 dB，与分析结果基本一致。     

纯电动客车电机动力总成悬置系统的优化设计

建立某纯电动客车电机动力总成悬置系统的刚体动力学模型,分析电机动力总成激励,利用Adams软件进行悬置系统模态特性和频域响应特性的仿真分析。通过工程优化软件Isight与Matlab的集成,直接使用Isight中的多岛遗传算法对电机动力总成悬置系统进行优化设计,优化后的悬置系统隔振性能得到了提高。     

电驱动动力总成噪声识别与优化

纯电动汽车的动力总成与传统汽车存在着明显区别,其噪声源也有较大差异。以新型"低速重载"电驱动动力总成为研究对象,研究其在加速与匀速运行状态下的噪声情况,运用单体声功率及频谱分析的方法识别出变速器齿轮产生的啮合噪声是电驱动动力总成系统噪声产生的主要原因。然后采用参数化建模方法建立齿轮传动系统模型,通过齿轮微观修形和传递误差计算的方法对噪声贡献量大的啮合齿轮进行优化设计,从而改善电驱动动力总成系统的声学环境,为改进低噪声的动力总成设计提供理论依据。     

混沌免疫遗传算法在汽车悬置系统设计中的应用

传统的悬置系统参数优化方法容易使优化结果陷入局部最优,遗传算法因其易于早熟收敛而限制了实际优化效果,为此提出使用混沌免疫遗传算法对汽车动力总成悬置系统参数进行优化设计。优化设计中,以动力总成悬置系统六自由度能量解耦为目标函数,以悬置刚度和安装角度为优化变量,并考虑悬置系统的模态频率匹配、能量解耦率、悬置静态剪切和压缩变形等约束条件。优化结果表明,基于设计的寻优方法,改善动力总成悬置系统与整车匹配程度,提高动力总成悬置系统的隔振性能。     

A multifunctional 3.5 V iron-based phosphate cathode for rechargeable batteries

In the search for new positive-electrode materials for lithium-ion batteries, recent research has focused on nanostructured lithium transition-metal phosphates that exhibit desirable properties such as high energy storage capacity combined with electrochemical stability. Only one member of this class--the olivine LiFePO(4) (ref. 3)--has risen to prominence so far, owing to its other characteristics, which include low cost, low environmental impact and safety. These are critical for large-capacity systems such as plug-in hybrid electric vehicles. Nonetheless, olivine has some inherent shortcomings, including one-dimensional lithium-ion transport and a two-phase redox reaction that together limit the mobility of the phase boundary. Thus, nanocrystallites are key to enable fast rate behaviour. It has also been suggested that the long-term economic viability of large-scale Li-ion energy storage systems could be ultimately limited by global lithium reserves, although this remains speculative at present. (Current proven world reserves should be sufficient for the hybrid electric vehicle market, although plug-in hybrid electric vehicle and electric vehicle expansion would put considerable strain on resources and hence cost effectiveness.) Here, we report on a sodium/lithium iron phosphate, A(2)FePO(4)F (A=Na, Li), that could serve as a cathode in either Li-ion or Na-ion cells. Furthermore, it possesses facile two-dimensional pathways for Li+ transport, and the structural changes on reduction-oxidation are minimal. This results in a volume change of only 3.7% that--unlike the olivine--contributes to the absence of distinct two-phase behaviour during redox, and a reversible capacity that is 85% of theoretical.     

Control system design of hybrid fuel cell city bus

This paper introduced the design of the hybrid powertrain of the Fuel Cell City Bus demonstrated in 2008 Beijing Olympic Games. The configuration of the hybrid fuel cell powertrain was introduced. The safety of hydrogen storage and delivery system, the hydrogen leakage alarm system were developed. The real-time distributed control and diagnosis system based on the Time Trigger Controller Area Network (TTCAN) with 10 ms basic control period was developed. The concept and implementation of processor (or controller) monitor and process (or task) monitor technique based on the TTCAN were applied in this paper. The fault tolerant control algorithm of the fuel cell engine and the battery management system were considered. The demonstration experience verified that the fault tolerant control was very important for the fuel cell city bus.     

汽车动力总成悬置系统鲁棒优化算法

应用鲁棒优化设计理论,考虑设计变量的不确定性对优化设计结果的影响,建立鲁棒优化模型。以动力总成悬置系统能量解耦为目标,悬置刚度参数为设计变量,考虑设计目标的均值和标准差,建立动力总成悬置系统的鲁棒优化模型。针对粒子群算法求解容易陷入局部最优解的问题,采用混合粒子群算法对动力总成悬置系统的悬置刚度参数进行鲁棒优化,并用Monte Carlo方法进行分析,以考察设计值的变化对目标函数的影响。结果表明,优化方法可以有效提高悬置系统的鲁棒性。     

基于能量解耦法的动力总成悬置系统优化设计

以南汽IVECO某轻型客车为例,建立动力总成悬置系统的六自由度动力学模型,根据能量解耦法推导了有关公式,对动力总成悬置参数进行优化设计,结果表明,合理地选择动力总成的悬置参数有利于降低发动机的振动向车内传递,进而提高车辆乘坐的舒适性。     

CO2‐neutrale Mobilität als Herausforderung und Chance

CO₂‐neutral Mobility as a Challenge and an Opportunity – From the powertrain to the electrolyzer: Plasma surface technology along the energy chain Three concepts are suitable for CO₂‐neutral and sustainable mobility: First, the direct use of electrical energy for battery electric vehicles (BEV). Secondly, the conversion of regeneratively generated electricity into green hydrogen as an energy carrier for fuel cell electric vehicles (FCEV) and thirdly, the generation of synthetic fuels from green hydrogen. The technologies will complement each other in terms of vehicle weight, distance and required propulsion power. Regardless of the powertrain concept, plasma surface technology offers outstanding opportunities for the optimization of highly stressed tribological systems. For example, Triondur PVD and PACVD coating systems in the automotive industry, where they were initially used to prevent wear, have become an extremely valuable design element for increasing energy efficiency and CO₂ savings through friction reduction. As a result, more than 150 million components coated with Triondur were delivered worldwide in 2018. Defossilization of the energy chain requires increased industrialization of components for electrolyzers and fuel cells, such as the metallic bipolar plates of galvanic cells. Here, as well, plasma surface technology will play a key role in meeting the high demands for the required electrochemical properties and quality standards. For CO₂‐neutral and sustainable mobility, plasma surface technology will always be and remain an important key technology, regardless of the powertrain concept.