混合动力汽车发展综述

混合动力汽车是当前各国汽车产业的一个重要研究发展方向,我国混合动力汽车发展总体上还处于起步阶段。首先,简要介绍混合动力汽车发展背景,综述国内外混合动力汽车具有代表性的产品,并分析国内外技术发展情况,指出混合动力汽车目前主要面临的电池系统管理、动力分配等问题,最后对我国混合动力汽车发展方向提出相应建议。     

混合动力汽车发展综述

混合动力汽车是当前各国汽车产业的一个重要研究发展方向,我国混合动力汽车发展总体上还处于起步阶段。首先,简要介绍混合动力汽车发展背景,综述国内外混合动力汽车具有代表性的产品,并分析国内外技术发展情况,指出混合动力汽车目前主要面临的电池系统管理、动力分配等问题,最后对我国混合动力汽车发展方向提出相应建议。     

Adaptive control of a hybrid power system in electric vehicles

在由双向电源变换器连接动力电池组和超级电容组形成的电动汽车混合电源系统中,实现了双向电源变换器的电源外特性设计,通过实时检测动力电池组的放电电流,实现了超级电容组的充放电状态和电流的自适应控制.建立了电源变换器外特性模型,描述了动力电池组放电电流和超级电容组充放电电流之间的定量关系.在此基础上,设计了双向电源变换器的控制电路.试验结果表明,在城市工况下,混合电源系统中动力电池组的峰值放电电流降低了60%,这有利于提高动力电池组的使用耐久性.     

混合动力汽车能量回收制动控制策略研究

为了满足混合动力电动汽车(HEV)制动安全性的要求并使其有效地进行能量回收,在分析比较了不同能量回收制动控制策略的基础上,针对EQ7200HEV-C并联型混合动力汽车的制动系统设计开发了一种全新的综合制动控制策略.该控制策略采用逻辑门限控制逻辑对传统的液压制动力矩进行动态调整,采用模糊控制逻辑对电机施加的能量回收制动力矩进行动态调整,两者的有效结合确保了制动安全下的能量有效回收.仿真及试验结果验证了该控制策略的有效性和稳定性.     

混合动力电动车CAN协议的实时性研究

在研究了控制器局域网络(CAN)通讯模型的基础上,提出了一种新的基于Poisson过程和几何分布的错误统计模型,并分析了模型参数与节点发送误码率的关系.在此基础上,运用建立的数学模型研究了混合动力电动车网络协议的通讯实时性,详细分析了错误统计模型中参数λ、波特率、传送周期和数据场长度4个重要因素对信息传送失败概率的影响.最终提出了基于CAN的车载控制网络的设计原则,如尽量采用多发送缓存的CAN控制器,尽可能延长传送周期和尽量压缩数据场长度等.     

并联混合动力汽车复合电源控制策略的研究

通过对复合电源在混合动力汽车(HEV)中应用的研究,设计了针对某款并联式混合动力汽车的复合电源结构,并对其效率特性进行了分析,提出了复合电源的功率分配控制策略以及电池给超级电容充电策略,基于MATALAB/Simulink,建立了复合能量存储系统模型,并嵌入ADVISOR软件中,在城市道路循环UDDS工况下进行了仿真研究。仿真结果表明,通过采用该复合电源控制策略,可以充分发挥超级电容和蓄电池各自的优点,改善整车储能系统的存储效率,提高制动能量的回收效率。     

电磁耦合混合动力公交车发动机运行点控制的仿真研究

设计了公交车用电磁耦合双电机(发电机 电动机)混合动力方案,以期在保证功能的同时解决现有方案造价过高的问题.提出了一种基于电磁耦合系统效率最优化的新的发动机运行点控制策略(NECS),以期提高发动机的燃油经济性.利用在Matlab/Simulink/Stateflow环境下构建的电磁耦合混合动力公交车仿真模型,以上海公交车循环工况作为仿真工况,对NECS进行了仿真验证.结果表明,与传统策略相比,该策略的燃油经济性提高了5.6%.     

基于动态规划的PHEV全程能量管理策略研究

在电动汽车仿真平台上,根据实际车型及技术现状合理地设置动力参数,搭建了外接充电式混合动力电动汽车(PHEV)整车模型,在此基础上,结合PHEV的特点,分析了PHEV的控制系统结构,提出了一种以提高燃油经济性为目标的全新的基于动态规划(DP)的PHEV全程能量控制策略。该策略突破了目前PHEV采用的电量消耗-电量保持模式的能量优化管理思路。为了最大限度地使用电池能量,以电池荷电状态(SOC)在路程起点处达到上限值,在终点达到安全下限值为限制条件,运用动态规划算法使得全程燃料经济性最高。仿真结果表明,与传统的能量管理策略相比,基于DP的全程能量管理可大大提高燃料经济性。     

并联混合动力汽车控制系统设计及控制策略研究

为混合动力汽车建立了分层控制系统,并用最优控制和模糊逻辑等方法进行了控制策略的研究.并联混合动力汽车控制系统包括能量管理策略和能量管理策略的实现两个层面,能量管理策略层根据驾驶员输入和车辆状态确定动力传动系统各部件目标工作状态;能量管理策略实现层以行驶平顺性和离合器磨损为目标对发动机、电机、离合器和变速系统进行协调控制.仿真及试验结果表明,分层控制系统能够实现整车控制要求的功能以及整车的燃油经济性指标、行驶平顺性和离合器磨损指标等设计目标.     

并联式混合动力电动汽车多模式能量管理策略与D2P实时仿真

针对并联式混合动力电动汽车的能量控制问题进行了研究,提出了一种多模式能量管理策略.建立了整车模型,以负载力矩、电池荷电状态(SOC)和车速作为控制依据设计了多个工作模式间的切换逻辑,将模式切换状态作为控制变量引入到力矩分配算法中,实现了多工况下对发动机与电机的优化控制.结合US06、UDDS和EUDC等工况进行了Simulink系统仿真,结果表明所提出的能量管理策略较传统功率跟随策略相比可以提高燃油经济性约1.91％,且对于不同的工况具有良好的普遍适用性;基于D2P系统构建了硬件在环仿真平台,采用真实的驾驶员输入设备和控制器进行实时仿真,进一步表明所提出的能量管理策略合理有效且算法具有良好的实时性.     

A hybrid transient model for simulation of air-cooled refrigeration systems: Description and experimental validation

In this paper are described a hybrid dynamic model for transient simulation of refrigeration systems as well as dynamic experiments that have been performed on an air/water heap pump. The machine under consideration is made of an evaporator, a condenser, an expansion valve, a variable speed scroll compressor and a receiver. The refrigerant and second fluid flows in heat exchangers are approximated by a cascade of Continuous Stirred Tank Reactors (CSTRs). This model is quite flexible since a unique structure is used for the evaporator and the condenser models according to different boundary conditions. This is due to the use of a switching procedure between different configurations based on a phase stability test that is designed to ensure the continuity of the system simulation. An analytical thermodynamic model of the refrigerant based on an equation of state is used. Good agreement between simulation results and experimental data is achieved.     

Compact infrared cryogenic wafer-level camera: design and experimental validation

We present a compact infrared cryogenic multichannel camera with a wide field of view equal to 120°. By merging the optics with the detector, the concept is compatible with both cryogenic constraints and wafer-level fabrication. The design strategy of such a camera is described, as well as its fabrication and integration process. Its characterization has been carried out in terms of the modulation transfer function and the noise equivalent temperature difference (NETD). The optical system is limited by the diffraction. By cooling the optics, we achieve a very low NETD equal to 15 mK compared with traditional infrared cameras. A postprocessing algorithm that aims at reconstructing a well-sampled image from the set of undersampled raw subimages produced by the camera is proposed and validated on experimental images.     

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.     

斜纹机织碳纤维/环氧树脂复合材料性能及其在电动汽车轻量化设计中的应用

采用均质法和单胞有限元法, 研究了斜纹机织碳纤维/环氧树脂复合材料的三维本构模型, 并应用于轻量化电动汽车结构的设计计算中。通过光学显微镜观测获得T300碳纤维/环氧树脂复合材料层合板细观结构几何参数, 依据参数建立了代表体积元的几何模型; 结合有限元分析方法与层合板理论对代表体积元模型进行受力分析, 获得了复合材料三维本构模型参数, 并运用单向拉伸与三点弯曲物理试验对所建立的本构模型进行了验证; 通过二次开发, 把该三维本构模型用于轻量化电动汽车结构件的设计中, 并根据汽车安全测试标准对所设计的结构进行了强度校核。研究表明: 运用所建立的三维材料本构模型进行的仿真实验结果与真实拉伸和弯曲试验结果相吻合, 误差分别为4.04%和7.79%, 可用于轻量化结构的设计; 研究开发的电动汽车, 轻量化效果明显, 在满足车身强度要求下整车质量减轻了12%。      

Unexpected discoveries and S-invention of design requirements: important vehicles for a design process

Designers, during a conceptual design process, do not just synthesize solutions that satisfy initially given requirements, but also invent design issues or requirements that capture important aspects of the given problem. How do they do this? What becomes the impetus for the invention of important issues or requirements? So-called ‘unexpected discoveries', the acts of attending to visuo-spatial features in sketches which were not intended when they were drawn, are believed to contribute to it. The purpose of the present research is to verify this hypothesis. Analysing the cognitive processes of a practising architect in a design session, we found that in about a half of his entire design process there were bi-directional relations between unexpected discoveries and the invention of issues or requirements. Not only did unexpected discoveries become the driving force for the invention of issues or requirements, but also the occurrence of invention, in turn, tended to cause new unexpected discoveries. This has provided empirical evidence for two anecdotal views of designing. First, designing is a situated act; designers invent design issues or requirements in a way situated in the environment in which they design. We call inventions of this sort situated-invention (S-invention). Secondly, a design process progresses in such a way that the problem-space and the solution-space co-evolve. Further, this has brought a pedagogical implication as well as an insight about an important aspect of learning by experience in design.     

一种电动汽车谐振式无线供电系统的研究

针对谐振式无线供电系统初级线圈和次级线圈相对位置变化引起接收功率及输出电压变化的现象,以及二极管整流导致次级电路电流畸变和功率因数下降等问题,提出了一种基于PWM整流的电动汽车谐振式无线供电系统,即采用电压外环及电流内环的双环控制方法,以保证供电系统的单位功率因数及直流电压的恒定输出,并且利用ANSYS和MATLAB/Simulink仿真软件,分别研究电动汽车停车充电位置偏差对互感的影响及基于PWM整流的谐振式无线供电系统的性能,仿真结果验证了方案设计的有效性.     

Performance evaluation of a vapor injection heat pump system for electric vehicles

Battery-powered electric vehicles (EV) need an efficient electric heating system for extending the driving mileage. An air-source heat pump system offers an economical alternative for EV because it consumes less energy than a heating system using Joule heat and it can use the same components as an air conditioning system for cooling. However, its performance degradation is inevitable at very low ambient temperatures. Although vapor refrigerant injection is known as a good technology to overcome this problem in residential heat pump systems, the number of vapor injection heat pump studies for EV applications is quite limited. In this paper, considering the characteristics of EV application, the configuration of a vapor injection heat pump system for EV is introduced, and it was modeled, using a scroll compressor geometry-based thermodynamic analysis. The performance was estimated for cold ambient regions under the EV operational conditions.     

Thermal-fluid and electromagnetic coupling analysis and test of a traction motor for electric vehicles

This paper proposes a multi-phasic coupling analysis and test of a 50 kW traction motor for electric vehicles. The temperature-dependent properties of the electrical and magnetic materials of the interior permanent magnet traction motor are not negligible over a wide operation range of the vehicle. The heat produced by the electromagnetic power loss changes the motor’s properties, and in turn the motor performance changes to produce a different power loss. This two-way coupled electromagnetic and thermal-fluid analysis of the torque and speed curve and the transient thermal response at a rated operation point are simulated and compared with the traditional one-way coupling analysis. The simulation results are also compared with and proved by experiments on a prototype motor. The experimental results show that it is critical and necessary to predict the motor performance by means of the proposed two-way coupling analysis that provides more accurate information than the traditional one-way coupling analysis.