纯电动商用车制动能量回收策略研究

为了提升纯电动商用车的制动能量回收效率,提高整车的续航里程。根据ECE法规和前后轮理想制动分配曲线,设计了一种适用于以后轮为驱动轮的制动力分配曲线,并提出了一种串联制动能量回收策略。在AVL-CRUISE中完成纯电动商用车的模型,在NEDC工况下完成并联策略与串联策略的仿真,串联策略比并联策略的制动能量回收效率提高了8%。结果表明串联制动能量回收策略能够大大提高纯电动商用车的制动回收效率,是提升纯电动商用车续航的有效方法。     

电动汽车真空助力制动系统的计算研究

分析了电动汽车安装电动真空助力制动系统的必要性。对真空助力制动系统的性能进行了分析计算,设计了电动真空泵最小真空度的计算流程。以改装的某型电-电混合动力轻型客车为例,给出了完整的制动系统的计算参数。计算结果表明,当电动真空泵最小真空度为37.5 kPa时,可为制动系统提供满足设计要求的制动助力。整车初步试验表明,所匹配的电动真空泵参数合理。     

基于滑移率和ABS的电动商用车制动性能控制研究

针对电动商用车在低附路面ABS激活后制动平顺性较差的问题,设计基于滑移率和ABS的制动性能控制系统。系统在ABS激活前通过调节制动扭矩,降低ABS激活概率;在ABS激活后通过控制电制动取消速率,并耦合正常状态电制动MAP,从而改善制动平顺性。     

增程/插电式电动商用车控制策略和经济性分析

对一款增程/插电式电动商用车进行研发。设计了该电动车辆的系统拓扑结构,分析了其工作原理。基于中国典型城市工况下进行了车辆的行驶仿真,得到了增程/插电式商用车的油耗和经济性。     

新能源汽车三电系统功能安全技术分析

<正>为了提高新能源汽车“三电系统”功能安全水平,以某款纯电动商用车为研究对象,阐述该款纯电动商用车“三电系统”架构设计,分别介绍动力电池系统、电机系统、电控系统功能安全技术。结果表明,该款纯电动商用车“三电系统”架构设计合理,“三电系统”功能安全水平较高。由此得出新能源汽车“三电系统”必须可靠安全,才能全面改善新能源汽车安全性,促进新能源汽车发展上升到新维度。     

纯电动轻型商用车驱动电机与动力电池选型

通过对纯电动轻型商用车的开发设计,阐述根据整车主要性能的要求,对驱动电机与动力电池的选型进行合理计算和设计匹配,为纯电动轻型商用车的电驱动系统初步选型提供设计依据,并使其满足整车动力性及可靠性的要求。     

轻型商用车集成式电子液压制动系统助力策略设计

伴随轻型商用车电动化的发展,用于轻型商用车的线控制动技术得到发展,针对线控制动技术中的集成式电子液压制动系统,提出一种基于模糊PI控制反应盘主副面位移差的制动助力方法。通过实车验证表明:实际反应盘主副面位移差能够快速跟随目标曲线,制动过程平顺,具有实用性。     

中央财政将再投40亿补贴新能源汽车

工业和信息化部副部长苏波日前透露，中央财政将对新能源汽车推广再投入40亿元的补贴资金，重点是纯电动乘用车和插电式乘用车、纯电动商用车和插电式商用车、燃料电池乘用车、动力电池等项目。     

面向电动客车的新型涡流缓速-制热系统研究

针对纯电动客车冬季取暖时续航里程大幅下降问题,提出一种制动能量高效利用新方法,设计了面向电动客车的新型涡流缓速-制热系统。通过机-电-磁集成制动系统制动稳定性和涡流缓速-制热机理等的研究,建立了该系统的制动控制策略,对涡流缓速器进行了仿真和台架试验,为提升电动客车的续驶里程和行驶安全提供了一种新思路。     

电动客车制动能量回收分析研究

通过对电动大客车复合制动系统特点的分析、制动控制策略原则的制定及对制动能量回收影响因素的讨论,对一款电动大客车在中国典型城市工况下的制动能量回收过程进行了仿真,结果表明,车辆每百公里可回收约8.38度电,回收的制动能量能够有效增加其续驶里程。     

Improvement of drivability and fuel economy with a hybrid antiskid braking system in hybrid electric vehicles

When braking on wet roads, Antilock Braking System (ABS) control can be triggered because the available brake torque is not sufficient. When the ABS system is active, for a hybrid electric vehicle, the regenerative brake is switched off to safeguard the normal ABS function. When the ABS control is terminated, it would be favorable to reactivate the regenerative brake. However, recurring cycles from ABS to motor regenerative braking could occur. This condition is felt to be unpleasant by the driver and has adverse effects on driving stability. In this paper, a novel hybrid antiskid braking system using fuzzy logic is proposed for a hybrid electric vehicle that has a regenerative braking system operatively connected to an electric traction motor and a separate hydraulic braking system. This control strategy and the method for coordination between regenerative and hydraulic braking are developed. The motor regenerative braking controller is designed. Control of regenerative and hydraulic braking force distribution is investigated. The simulation and experimental results show that vehicle braking performance and fuel economy can be improved and the proposed control strategy and method are effective and robust.     

基于混杂理论的电磁与摩擦集成制动方法

鉴于传统电子液压制动系统连续制动易产生"热衰退"现象，结构缺陷导致的制动响应慢，制动系统与电控系统衔接差等缺点，提出了一种基于混杂自动机模型的电磁与摩擦集成制动方法。首先分析集成制动器制动时的工作特点以及不同情况下对应的工作模式（纯电磁制动、纯摩擦制动以及集成制动），并确定3种制动模式的切换条件，通过逻辑门限算法将其实现。根据制动时车辆既具有连续运动状态又有离散状态的混杂特性，使用MATLAB/Stateflow建立基于制动模式切换系统的推广自动机模型，并根据制动模式切换控制策略，对3种制动模式切换进行试验，验证制动模式切换控制策略的合理性。最后选取车辆制动初速度为28 m·s^-1的直线制动工况，分别在高附着系数（0.85）以及低附着系数（0.3）的路面条件下，通过试验平台对控制算法和制动系统性能进行试验验证。研究结果表明：所提出的汽车混杂理论模型以及优化方法在在低附着系数（0.3）路面条件下，集成制动方法较传统液压制动系统缩短5.12%的制动距离，缩短制动时间0.3 s；在高附着系数（0.85）路面条件下，集成制动方法较传统液压制动系统缩短5.66%的制动距离，缩短制动时间0.2 s，能有效提高制动效能。     

Cooperative regenerative braking control for front-wheel-drive hybrid electric vehicle based on adaptive regenerative brake torque optimization using under-steer index

In this study, cooperative regenerative braking control of front-wheel-drive hybrid electric vehicle is proposed to recover optimal braking energy while guaranteeing the vehicle lateral stability. In front-wheel-drive hybrid electric vehicle, excessive regenerative braking for recuperation of the maximum braking energy can cause under-steer problem. This is due to the fact that the resultant lateral force on front tire saturates and starts to decrease. Therefore, cost function with constraints is newly defined to determine optimum distribution of brake torques including the regenerative brake torque for improving the braking energy recovery as well as the vehicle lateral stability. This cost function includes trade-off relation of two objectives. The physical meaning of first objective of cost function is to maximize the regenerative brake torque for improving the fuel economy and that of second objective is to increase the mechanical-friction brake torques at rear wheels rather than regenerative brake torque at front wheels for preventing front tire saturation. And weighting factor in cost function is also proposed as a function of under-steer index representing current state of the vehicle lateral motion in order to generalize the constrained optimization problem including both normal and severe cornering situation. For example, as the vehicle approaches its handling limits, adaptation of weighting factor is possible to prioritize front tire saturation over increasing the recuperation of braking energy for driver safety and vehicle lateral stability. Finally, computer simulation of closed loop driver-vehicle system based on Carsim? performed to verify the effectiveness of adaptation method in proposed controller and the vehicle performance of the proposed controller in comparison with the conventional controller for only considering the vehicle lateral stability. Simulation results indicate that the proposed controller improved the performance of braking energy recovery as well as guaranteed the vehicle lateral stability similar to the conventional controller.     

电—液混合式制动系统试验台的开发

以电动汽车开发为例,设计了电—液混合式制动系统试验台。介绍了试验台设计、总体结构方案设计、硬件设计及控制系统设计。实际测试表明,该试验台可用于测试防抱制动控制算法的控制性能和电机再生制动性能、研究电—液制动力分配控制策略,并能够模拟在较小横摆角条件下直接横摆扭矩对制动状态的影响。     

插电式混合动力汽车再生制动控制策略

由于再生制动控制策略直接影响了插电式混合动力汽车（PHEV）的经济性,文章提出了一种基于理想制动力分配的再生制动控制策略,这种策略能在保证制动稳定性的同时,尽可能多地回收制动能量,在Simulink平台上建立再生制动控制策略模型,并嵌入到Cruise软件中进行仿真。仿真结果表明,此模型相比没有制动能量回收的PHEV和传统汽车,都有效地提高了经济性,验证了再生制动控制策略的合理性。     

Extended-Kalman-filter-based regenerative and friction blended braking control for electric vehicle equipped with axle motor considering damping and elastic properties of electric powertrain

Because of the damping and elastic properties of an electrified powertrain, the regenerative brake of an electric vehicle (EV) is very different from a conventional friction brake with respect to the system dynamics. The flexibility of an electric drivetrain would have a negative effect on the blended brake control performance. In this study, models of the powertrain system of an electric car equipped with an axle motor are developed. Based on these models, the transfer characteristics of the motor torque in the driveline and its effect on blended braking control performance are analysed. To further enhance a vehicle's brake performance and energy efficiency, blended braking control algorithms with compensation for the powertrain flexibility are proposed using an extended Kalman filter. These algorithms are simulated under normal deceleration braking. The results show that the brake performance and blended braking control accuracy of the vehicle are significantly enhanced by the newly proposed algorithms.     

Wheel slip control with torque blending using linear and nonlinear model predictive control

Modern hybrid electric vehicles employ electric braking to recuperate energy during deceleration. However, currently anti-lock braking system (ABS) functionality is delivered solely by friction brakes. Hence regenerative braking is typically deactivated at a low deceleration threshold in case high slip develops at the wheels and ABS activation is required. If blending of friction and electric braking can be achieved during ABS events, there would be no need to impose conservative thresholds for deactivation of regenerative braking and the recuperation capacity of the vehicle would increase significantly. In addition, electric actuators are typically significantly faster responding and would deliver better control of wheel slip than friction brakes. In this work we present a control strategy for ABS on a fully electric vehicle with each wheel independently driven by an electric machine and friction brake independently applied at each wheel. In particular we develop linear and nonlinear model predictive control strategies for optimal performance and enforcement of critical control and state constraints. The capability for real-time implementation of these controllers is assessed and their performance is validated in high fidelity simulation.     

轻度混合动力汽车制动能量回收控制策略研究

以某轻度混合动力电动汽车为研究对象,分析了,制动能量回收系统在制动回收工作过程中的控制策略,并在分析的基础上建立其在制动过程中的制动力分配模型和数学模型,利用6个典型的循环工况来评价现有制动力分配策略的优劣,并与Advisor中的制动力分配策略进行了比较。无论是燃油经济性、整车能量效率、回收能量占燃油消耗的百分比,还是能量回收率都有明显的提高。     

Development of an electric booster system using sliding mode control for improved braking performance

Brake systems of the future, including BBW (Brake-by-Wire), are in development in various forms. In one of the proposed hydraulic BBW systems, an electric booster system replaces the pneumatic brake booster with an electric motor and a rotational-to-linear motion mechanism. This system is able to provide improved braking performance by the design of controllers with precise target pressure tracking and control robustness for better system reliability. First, a sliding mode controller is designed using the Lyapunov function approach to secure the robustness of the system against both the model uncertainty and the disturbance caused by the master cylinder and mechanical components. Next, a simulation tool is constructed to validate the electric booster system with the proposed controller. Finally, the electric booster system is implemented into an actual brake ECU and installed in a vehicle for testing under various braking conditions. The experimental results demonstrate that the proposed controller produces faster pressure build-up performance than the conventional brake system, and its tracking performance is sufficient to ensure comfortable braking.     

Transient switching control strategy from regenerative braking to anti-lock braking with a semi-brake-by-wire system

Regenerative braking is an important technology in improving fuel economy of an electric vehicle (EV). However, additional motor braking will change the dynamic characteristics of the vehicle, leading to braking instability, especially when the anti-lock braking system (ABS) is triggered. In this paper, a novel semi-brake-by-wire system, without the use of a pedal simulator and fail-safe device, is proposed. In order to compensate for the hysteretic characteristics of the designed brake system while ensure braking reliability and fuel economy when the ABS is triggered, a novel switching compensation control strategy using sliding mode control is brought forward. The proposed strategy converts the complex coupling braking process into independent control of hydraulic braking and regenerative braking, through which a balance between braking performance, braking reliability, braking safety and fuel economy is achieved. Simulation results show that the proposed strategy is effective and adaptable in different road conditions while the large wheel slip rate is triggered during a regenerative braking course. The research provides a new possibility of low-cost equipment and better control performance for the regenerative braking in the EV and the hybrid EV.