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.     

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.     

并行再生制动系统控制器的设计与开发

分析了混合动力汽车再生制动系统的特点及其应用前景,提出了一种基于并行控制的再生制动控制策略;针对某款并联式混合动力轿车,采用并行再生制动控制策略,进行了制动控制器的软硬件开发;搭建了硬件在环仿真试验系统对控制器进行了硬件在环仿真验证,并对控制器进行了实车测功机试验和实车道路试验。试验结果表明:该控制器运行稳定、可靠,整车平均制动能量回收效率达15%左右,显著提高了汽车的能源利用效率。     

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%。     

汽车节能新技术——再生制动技术

再生制动技术是一种有效的节能方式，对再生制动技术进行了理论研究，分析了再生制动技术的节能原理，从传动方式和能量存储方式上研究汽车的再生制动技术。并对再生制动汽车的功率流进行了分析。     

基于模糊逻辑的电动汽车制动能量回馈系统

分析了电动汽车制动能量回馈的特点，针对电动汽车制动能量回馈时强鲁棒性的需求，设计了一种基于Sugeno模糊逻辑的制动能量回馈系统，以满足能量回馈的要求，该回馈系统提高了整车的制动性能以及续驶里程，也使整车的动力性、安全性和舒适性达到较好的平衡，文章同时估算了这种控制策略的能量回收效率。经仿真和实际测试，结果表明所提策略满足总体设计的性能指标要求。     

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。     

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.     

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。     

Fault-tolerant braking control with integerated EMBs and regenerative in-wheel motors

This paper presents a fault-tolerant brake torque controller for four-wheel-distributed braking systems with in-wheel motors and Electro-Mechanical Brakes (EMB). Mechanical and electrical faults can degrade the performance of the EMB actuators and, thus, their effects need to be compensated in vehicle dynamics level. In this study, the faults are identified as performance degradation and expressed by the gains of each actuator. Assuming the brake force distribution and the regenerative braking ratios, the over-actuated braking system is simplified into a two-input system. A sliding mode controller is designed to track the driver’s braking and steering commands, even if there exist faults in EMBs. In addition, adaptive schemes are constructed to achieve the fault-tolerant control in braking. The proposed controller and strategies are verified in the EMB HILS (Hardware-in-loop-simulation) unit for various conditions.     

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。     

Cooperative control for friction and regenerative braking systems considering dynamic characteristic and temperature condition

The braking system of hybrid electric vehicle (HEV) is composed of friction and regenerative braking system, meaning that braking torque is generated by the collaboration of the friction and regenerative braking system. With the attributes, there are two problems in the HEV braking system. First, rapid deceleration occurs due to dynamic characteristic difference when shifting the friction and regenerative braking systems. Second, the friction braking torque alters with temperature because the friction coefficient changes with the temperature. These problems cause the vehicle to be unstable. In this paper, the concurrence control and compensation control were proposed to solve these problems. And also, the concurrence control and compensation control were combined for the stability of the braking system. In order to confirm the effect of these control algorithms, the experiment and simulation were conducted. Consequently, it was confirmed that the control algorithm of this study improved the vehicle safety and stability.     

纯电动汽车制动能量回收系统关键技术现状分析

文章以制动能量回收控制策略为核心,展开制动能量回收系统关键技术现状分析。首先重点阐述制动能量回收前后轴制动力与电-液制动力分配原则与技术要点。其后提出电机性能、储能装置性能状态、再生制动系统结构、行驶工况四类关键因素对制动能量回收的影响,并对其关键技术的研究现状进行综合分析。最后提出制动能量回收系统未来的研究方向。     

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。     

Regenerative braking strategies,vehicle safety and stability control systems: critical use-case proposals

The sustainable development of vehicle propulsion systems that have mainly focused on reduction of fuel consumption (i.e. CO₂ emission) has led, not only to the development of systems connected with combustion processes but also to legislation and testing procedures. In recent years, the low carbon policy has made hybrid vehicles and fully electric vehicles (H/EVs) popular. The main virtue of these propulsion systems is their ability to restore some of the expended energy from kinetic movement, e.g. the braking process. Consequently new research and testing methods for H/EVs are currently being developed. This especially concerns the critical ‘use-cases’ for functionality tests within dynamic events for both virtual simulations, as well as real-time road tests. The use-case for conventional vehicles for numerical simulations and road tests are well established. However, the wide variety of tests and their great number (close to a thousand) creates a need for selection, in the first place, and the creation of critical use-cases suitable for testing H/EVs in both virtual and real-world environments. It is known that a marginal improvement in the regenerative braking ratio can significantly improve the vehicle range and, therefore, the economic cost of its operation. In modern vehicles, vehicle dynamics control systems play the principal role in safety, comfort and economic operation. Unfortunately, however, the existing standard road test scenarios are insufficient for H/EVs. Sector knowledge suggests that there are currently no agreed tests scenarios to fully investigate the effects of brake blending between conventional and regenerative braking as well as the regenerative braking interaction with active driving safety systems (ADSS). The paper presents seven manoeuvres, which are considered to be suitable and highly informative for the development and examination of H/EVs with regenerative braking capability. The critical manoeuvres presented are considered to be appropriate for examination of the regenerative braking mode according to ADSS. The manoeuvres are also important for investigation of regenerative braking system properties/functionalities that are specified by the legal requirements concerning H/EVs braking systems. The last part of this paper shows simulation results for one of the proposed manoeuvres that explicitly shows the usefulness of the manoeuvre.     

并联混合动力客车再生制动仿真研究

建立了并联式混合动力汽车动力学模型,并对纯电机制动模式和机电混合模式混合动力汽车能量再生制动进行了仿真。仿真结果表明：对于纯电机模式,制动效能低,能量回收率达29％;对于机电混合制动模式,制动效能高,能量回收率仅2％。     

模糊PID控制的电动汽车再生制动系统变换器的研究

提出了利用超级电容作为储能元件实现电动汽车再生制动的能量回收方案,分析了电动汽车控制系统的双向DC/DC变换器和电机驱动器的驱动降压电路、制动升压电路,设计了该控制系统的模糊自整定PID控制器。通过仿真研究表明,在车辆驱动降压变换时,模糊自整定PID控制的超级电容器在150 A左右的大电流放电情况下,超级电容仍能维持2.5 s的指定电压输出,车辆在额定功率下工作,通过降压变换,超级电容储存的能量迅速供给电机,有效提高了驱动电流,改善了起动及加速性能,有效增加了续驶里程。在制动升压变换时,模糊自整定PID控制的超级电容器电流基本跟随指令值上下波动,超级电容电压从120 V不断上升,使得该电容器的储能能力得到充分利用,实现了高水平的能量回收。     

电子机械式制动执行器硬件在环仿真

电子机械制动技术是一种全新的制动理念,极大的提高了汽车的制动安全性.文中介绍了电子机械制动系统的发展、组成及工作原理;搭建了电子机械式制动执行器原理机硬件在环仿真试验平台.以1/4车辆模型为研究对象,对基于模糊控制方法的车辆防抱死制动特性的Matlab/Simulink仿真结果和硬件在环仿真结果进行比较分析.验证了电子机械式制动执行器的合理性和可行性.     

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。     

Fault detection and diagnosis of the electromechanical brake based on observer and parity space

In the future, the conventional hydraulic brake system in automobiles will be removed and replaced by an electrically operated brake system called brake-by-wire. The brake-by-wire units, such as the EMB (Electro-Mechanical Brake), provide better braking performance by directly controlling the brake motor and are environmentally friendly because they do not use hydraulic fluid. For implementation of the EMB systems, reliable and robust fault detection and diagnosis methods become increasingly important. In this study, a sensor fault diagnosis method is proposed with parity space and observer approaches to detect faults in the motor current sensor, speed (or position) sensor and clamping force sensor. The proposed method is verified through a closed-loop simulation using Matlab/Simulink, and the simulation result is compared with the HILS bench test results.