一种电动汽车制动能量回收系统研究

文章以某款纯电动车制动能量回收系统为研究对象,首先,设计一种电液助力系统,阐述其结构方案和工作原理,接着基于该电液助力系统开展纯电动车串行制动能量回收系统设计研究,包括结构方案、控制方案、电气方案;实现在某款纯电动车产品上的搭载应用开发,结果表明,基于该电液助力系统的纯电动车能量回收系统,实现车辆在制动或减速阶段,机械-液压制动力与电机回馈制动力实时协调,最大限度地回收制动能量,并且获得较好的制动稳定性和“踏板感”,单个ECE循环工况经济性贡献率最高达28.9%。     

新能源汽车再生制动能量回收研究综述

续驶里程及蓄电池供电技术是目前制约新能源汽车普及的主要因素。再生制动技术作为提高整车能量利用率的有效方案，为新能源汽车续驶里程的提高提供了一条切实可行的解决思路。针对再生制动关键技术，分别阐述了再生制动控制策略研究和再生制动能量管理研究两个方面的研究成果。针对再生制动策略问题，分别从制动意图识别、制动力分配以及轮缸压力控制三方面总结了再生制动相关控制策略；针对能量管理问题，分别从制动能量回收潜力与能量回收效果评估两方面对研究成果进行了总结。分析了通过能量流机理计算车辆节能潜力的方法，并对未来再生制动关键技术的研究与发展趋势进行了展望。     

纯电动汽车制动能量回收控制策略及仿真分析

整车控制系统是车辆的核心控制部分,其既要对驾驶员的操纵意图进行识别和判断,又要对整车运行时的关键参数进行监测和控制,同时,还要对整车的能量需求进行管理和协调。在车辆制动工况下,如果进行制动能量的回收控制,可以有效的延长续驶里程,但电动汽车在进行回馈制动时,电制动会和机械制动系统相互耦合,这一问题解决的好坏,也会影响到车辆行使的安全性。本文阐述了对制动模式下机械制与电机再生制动的协调开展研究,目标是进一步保证车辆行驶的安全性和舒适性,提高制动时的能量回收效率。     

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。     

电动汽车复合制动控制研究现状综述

电动汽车复合制动由电机再生制动与机械摩擦制动两部分构成,其控制性能直接影响车辆的能量利用效率、制动安全性以及舒适性。围绕静态制动转矩分配控制、动态复合制动协调控制、制动换挡控制、智能辅助驾驶中的复合制动控制4个方面的研究现状与关键技术展开综述,并对复合制动控制未来研究方向进行了展望。对文献的梳理分析表明：制动转矩分配决定着复合制动系统能量回收能力与车辆制动稳定性,基于规则的分配策略面对复杂多变工况自适应性欠佳,而基于优化的分配策略各方面性能表现良好,但需要兼顾控制实时性与优化效果;利用电机响应迅速与控制精确的优势完成复合制动协调控制,能够提升制动模式切换过渡工况与紧急制动工况的控制性能,改善驾驶舒适性;制动过程中实施合理换挡可以进一步提升能量回收效率,同时通过补偿控制解决换挡过程中动力中断和转矩冲击等问题,保证换挡平顺性;随着电动汽车智能化和网联化发展,复合制动控制与驾驶人辅助系统相结合有助于在保证系统功能的同时实现能量回收效益最大化。     

基于电机最优回馈转矩曲线的制动控制策略

本文中首先基于电机等效电路模型,分析了车用内置式永磁同步电机的耗能制动状态和回馈制动状态;然后根据电机矢量控制原理,对控制电流指令进行解析,并经试验数据的验证;接着计算得到永磁同步电机最优回馈转矩曲线,并据此提出一种制动回馈能量最优的串联制动控制策略。最后针对某P4并联混合动力商用车,仿真分析了在C?WTVC、CHTC?TT循环工况和试验采集到的某段省道工况下,并联制动和所提出的串联最优制动控制策略下的百公里油耗和制动回收能量。结果表明,与并联制动控制相比,基于电机最优回馈转矩曲线的串联制动控制策略可降低油耗,并回收更多的制动能量,实现制动回收能量和燃油经济性的提升。     

An integrated control strategy for the composite braking system of an electric vehicle with independently driven axles

For an electric vehicle with independently driven axles, an integrated braking control strategy was proposed to coordinate the regenerative braking and the hydraulic braking. The integrated strategy includes three modes, namely the hybrid composite mode, the parallel composite mode and the pure hydraulic mode. For the hybrid composite mode and the parallel composite mode, the coefficients of distributing the braking force between the hydraulic braking and the two motors' regenerative braking were optimised offline, and the response surfaces related to the driving state parameters were established. Meanwhile, the six-sigma method was applied to deal with the uncertainty problems for reliability. Additionally, the pure hydraulic mode is activated to ensure the braking safety and stability when the predictive failure of the response surfaces occurs. Experimental results under given braking conditions showed that the braking requirements could be well met with high braking stability and energy regeneration rate, and the reliability of the braking strategy was guaranteed on general braking conditions.     

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.     

基于交通信息的电动汽车制动策略及仿真

为了提高滑行能量回收经济性和踏板制动安全性、舒适性,基于交通信息,提出了电动汽车(EV)制动协调策略。分析了滑行制动的经济性,由交通信息和汽车行驶状态确定滑行制动强度;由道路信息和前方车辆信息建立汽车安全距离模型和碰撞预警策略,利用预警信息对滑行制动和踏板制动强度进行协调。对本策略进行仿真验证。结果表明:利用交通信息的滑行策略,在通行良好工况下综合能耗减少1.1%,拥堵工况下减轻驾驶员的制动疲劳;预警和协调策略避免了频繁预警,减小了紧急避撞触发几率。因此,利用交通信息能够辅助驾驶员进行更加合理的制动。     

Effect of regenerative braking energy on battery current balance in a parallel hybrid gasoline-electric vehicle under FTP-75 driving mode

In recent years, a hybrid electric vehicle (HEV) has been considered a successful technology. Especially, in case of a full HEV, the motor can drive the vehicle by itself at low velocity or assist the engine at high load. To improve the hybrid electric vehicle’s efficiency, a regenerative braking system is also applied to recover from kinetic energy. In this study, an experimental control apparatus was set up with a parallel hybrid electric vehicle mounted on a chassis dynamometer to measure ECU (engine control unit) and MCU (motor control unit) signals, including the current and state of charge in the battery. In order to analyze regenerative braking characteristics, user define braking driving cycle was introduced and carried out using different initial velocities and braking times. The FTP 75 driving cycle was then adapted under different initial SOC (state of charge) levels. The experiment data was analyzed in accordance with the vehicle velocity, battery current, instant SOC level, motor RPM, engine RPM, and then vehicle driving mode was decided. In case of braking driving cycle, it was observed that SOC were increased up to 1.5 % when the braking time and the velocidy were 6 second and 60 km/h, respectively. In addition, using the FTP 75 driving cycle, mode 1 was most frequently operated at SOC 65 conditions in phase 1. In phase 2, due to frequent stop-go hills, percentage of mode 1 was increase by 22 %. Eventually, despite of identity, it was shown that the characteristics of phase 3 differed from phase 1 due to the evanishment of the effects of initial SOCs.     

能量回收式电涡流缓速器制动策略研究

文章结合电涡流缓速器和再生制动能量回收技术的优点,提出了能量回收式电涡流缓速器制动补偿策略。利用再生制动系统提供的制动力矩为电涡流缓速器在持续制动过程中的制动力矩热衰退予以补偿。以GB12676-2014政策法规为验证标准,车辆在满载情况下在7%的坡道上保持以30km/h的车速匀速行驶5km为仿真目标,对某商用车型进行仿真分析。验证了该策略使得实际产生的总制动力矩始终能满足驾驶员的制动需求,可以延缓电涡流缓速器温升,保障车辆行车安全。     

直流无刷电机再生制动系统试验台的设计与验证

基于再生制动理论,以电动汽车用轮毂电机为主体,搭建了直流无刷电机再生制动试验台。以回收能量最大化为目标,提出了相应的再生制动控制策略。结合电机的输出特性和工作原理,利用SIMULINK软件建立了再生制动系统模型。通过模型仿真和试验台试验结果的对比分析,验证了再生制动试验台设计方案的可行性和控制策略的合理性。     

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.     

纯电动乘用车关键系统设计研究及分析验证

本文主要针对某纯电动乘用车进行关键系统选型及匹配分析,首先基于整车性能目标及整车性能参数,确定其动力驱动方式及制动能量回收策略和方案。其次为了更好提升整车能量管理水平,改善能耗,提升续航里程,本文研究的纯电动汽车制动系统采用电液助力系统(IBS)。IBS系统能够有效进行能量计算,确定液压系统是否介入工作,在满足制动需求的同时,改善整车能耗,提升续航里程。最后,在关键系统选型及设计分析上,利用MATLAB仿真软件进行性能初选及设计,结合AMEsim分析软件对选型结果进行加速性能及中国工况续驶里程数据校核,通过仿真与整车试验验证整车性能满足设计指标。     

串联式复合电源再生制动系统恒流控制

再生制动技术可以有效回收车辆制动能量，是提高电动汽车续驶里程的重要途径，超级电容具有高功率密度、高效率的特点，利用蓄电池-超级电容组成的复合电源作为电动汽车的储能装置可以改善电池工作状态，提高电池寿命及可靠性，并提高能量回收率。目前使用复合电源（蓄电池-超级电容）进行再生制动的电动汽车多采用并联形式，针对此类状况，基于无源串联复合电源结构设计其再生制动系统，其主要由电机、超级电容组、整流桥和控制器组成。在控制策略上，采用电压反馈恒定电流制动方式，基于脉冲宽度调制（PWM）控制，在制动过程中根据电动汽车车速与超级电容端电压实时调节PWM的占空比以实现目标制动电流恒定。在MATLAB/Simulink平台上建立再生制动系统仿真模型，验证所提控制策略的有效性，并利用某电动汽车对所设计系统进行滑行、制动等试验。研究结果表明：相比有源并联式复合电源，该系统不需要DC/DC转换器，结构及控制简单，该系统能够较好地实现制动能量回收，所采用的控制策略能够有效地实现恒电流制动，电制动减速度稳定，同时具有较高的能量回收率。     

Modeling and control strategy development for fuel cell hybrid vehicles

Using MATLAB/Simulink, we constructed a comprehensive simulation model for the fuel cell hybrid vehicle (FCHV) power train in parallel with a power control strategy that uses a logic threshold approach implemented with a hybrid control unit (HCU). The simulation implements power flow and power distribution under different vehicle operating modes using the accelerator and decelerator pedal positions deduced from the driving schedule as primary inputs. The HCU control strategy also incorporates regenerative braking and recharging for recovery of battery capacity. Using the D-optimality method for selection of the optimal experiment values, three control threshold variables for the HCU are selected to maximize the hydrogen fuel economy under certain driving cycles. The proposed method provides the optimal configuration of the FCHV model, which has the capability of achieving the requested drive power while also meeting the vehicle driving schedule and recovery needs of the state of charge (SOC) battery, with lower fuel consumption levels.     

混合动力电动汽车制动系统回馈特性仿真

为了研究混合动力电动汽车(HEV)回馈制动特性,建立了用于城市公交的混合动力电动汽车复合制动系统的仿真模型,提出了回馈制动控制策略,分析了复合制动系统的工作过程,并探讨影响电动汽车制动系统可靠、安全和高效的主要因素,研究电动汽车复合制动系统优化途径。研究结果表明:回馈制动最低车速限值越小,制动能量回收率越大;从回收电动汽车能量角度分析,回馈制动比例应有一个有效范围值;在各种循环工况下,具有回馈制动功能时混合动力电动汽车城市客车单位里程的能量消耗可降低10%~25%。     

Combined control of a regenerative braking and antilock braking system for hybrid electric vehicles

Most parallel hybrid electric vehicles (HEV) employ both a hydraulic braking system and a regenerative braking system to provide enhanced braking performance and energy regeneration. A new design of a combined braking control strategy (CBCS) is presented in this paper. The design is based on a new method of HEV braking torque distribution that makes the hydraulic braking system work together with the regenerative braking system. The control system meets the requirements of a vehicle longitudinal braking performance and gets more regenerative energy charge back to the battery. In the described system, a logic threshold control strategy (LTCS) is developed to adjust the hydraulic braking torque dynamically, and a fuzzy logic control strategy (FCS) is applied to adjust the regenerative braking torque dynamically. With the control strategy, the hydraulic braking system and the regenerative braking system work synchronously to assure high regenerative efficiency and good braking performance, even on roads with a low adhesion coefficient when emergency braking is required. The proposed braking control strategy is steady and effective, as demonstrated by the experiment and the simulation.     

分布式驱动电动汽车回馈制动失效的液压补偿控制

分布式驱动电动汽车各驱动轮转速和转矩可以单独精确控制，便于实现整车动力学控制和制动能量回馈，从而提升车辆的主动安全性和行驶经济性。但车辆在回馈制动过程中，一旦1台电机突发故障，其他电机产生的制动力矩将对整车形成附加横摆力矩，从而造成车辆失稳，此时虽可通过截断异侧对应电机制动力矩输出来保证行驶方向，但会使车辆制动力大幅衰减或丧失，同样不利于行车安全。为了解决此问题，提出并验证一种基于电动助力液压制动系统的制动压力补偿控制方法，力图有效保证整车制动安全性。以轮毂电机驱动汽车为例，首先建立了整车动力学模型以及轮毂电机模型，通过仿真验证了回馈制动失效的整车失稳特性以及电机转矩截断控制的不足；然后，建立了电动助力液压制动系统模型，并通过原理样机的台架试验验证了模型的准确性；接着，基于滑模控制算法设计了制动压力补偿控制器，并在单侧电机再生制动失效后的转矩截断控制基础上完成了液压制动补偿控制效果仿真验证；最后，通过实车试验证明了所提控制方法的有效性和实用性。研究结果表明：在分布式驱动电动汽车单侧电机再生制动失效工况下，通过异侧电机转矩截断控制和制动系统的液压主动补偿，能够使车辆快速恢复稳定行驶并满足制动强度需求。     

ISG hybrid powertrain: a rule-based driver model incorporating look-ahead information

According to European regulations, if the amount of regenerative braking is determined by the travel of the brake pedal, more stringent standards must be applied, otherwise it may adversely affect the existing vehicle safety system. The use of engine or vehicle speed to derive regenerative braking is one way to avoid strict design standards, but this introduces discontinuity in powertrain torque when the driver releases the acceleration pedal or applies the brake pedal. This is shown to cause oscillations in the pedal input and powertrain torque when a conventional driver model is adopted. Look-ahead information, together with other predicted vehicle states, are adopted to control the vehicle speed, in particular, during deceleration, and to improve the driver model so that oscillations can be avoided. The improved driver model makes analysis and validation of the control strategy for an integrated starter generator (ISG) hybrid powertrain possible.