随着环境污染与能源危机的日益严峻，包括混合动力汽车、纯电动汽车以及燃料电池汽车在内的节能与新能源汽车成为了全球研发的热点。就城市工况下行驶的汽车而言，用于直接驱动车辆运行的能量大约有1/3到1/2被消耗在制动过程中。制动能量回收系统能在车辆减速或制动过程中，将其部分动能转化为电能储存于电池中，从而提高电驱动车辆的能量经济性。然而受到电池、电机等部件特性的影响，电机回馈制动力与传统摩擦制动力的产生、传递、作用机理不同，因此电机回馈制动的引入对现有汽车理论与控制方法提出了许多新问题。 本文以电驱动乘用车为对象开展研究，重点研究了制动能量回收系统方案、回馈能量管理策略、回馈制动过程液压制动力精密控制方法以及回馈制动力与摩擦制动力的动态耦合控制算法。 提出了具有轮缸压力调节和踏板感觉模拟双重功能的协调式制动能量回收系统新方案，通过液压调节机构与踏板模拟器的协同工作，规避了国外主流方案中高压蓄能器等主动建压部件的使用，大大降低了协调式制动能量回收系统的实施难度。 建立了包含电机回馈制动模型、液压制动系统模型、车辆动力学模型和轮胎模型在内的电动汽车制动能量回收系统模型。提出了兼顾能量回收效率、踏板感觉以及整车冲击的制动能量回收综合优化能量管理策略，解决了能量回收效率与制动舒适性冲突的技术难题。 建立了电磁阀“机-电-液”耦合动力学模型，证明了电磁阀阀芯临界开启平衡状态下，线圈电流与阀口两侧压差之间存在的线性对应关系。在此基础上，提出了新型液压力动态限压差控制方法，拓展了现有液压执行机构的控制方式，可大幅提高回馈制动过程中液压力的控制精度。 建立了电驱动传动系统动力学模型，分析了轴系弹性以及齿隙非线性环节对回馈制动转矩的动态影响规律。在此基础上，设计了基于混杂系统理论的电驱动系统状态观测器，提出了针对轴系弹性与齿隙耦合非线性的主动补偿控制方法，可抑制制动状态切换过程中回馈转矩的震荡，大幅提高耦合制动力的控制精度。
With the rising concern in global environmental issues and energy crisis, new energy vehicles, including hybrid electric vehicles, electric vehicle, and fuel cell electric vehicles, become worldwide research topics. In urban driving situations, about one third to one half of the energy used for directly driving the wheels is consumed during deceleration processes. A regenerative brake system, which has the ability to convert kinetic energy into electrical energy and stored in battery during decelerations, can significantly improve the energy efficiency of a vehicle. However, compared to the conventional friction brake, the regenerative brake presents quite different generation, transfer and response mechanisms, because of the effects exerted by the components of the electric powertrains. Thus, the utilization of the regenerative brake system presents tremendous challenges to the existing vehicle theories and control methods. Several key scientific problems of regenerative brake of electric passenger vehicles, including regenerative brake system design, comprehensive optimization strategy of regenerative energy management, high-precision control method of hydraulic braking pressure during regenerative decelerations, and dynamical blending control algorithm of regenerative brake and frictional brake, are investigated in this paper. A new type of cooperative regenerative braking system, which integrates the functions of wheel brake pressure modulation and brake pedal feel simulation, is proposed. By utilizing the hydraulic pressure modulating actuators and brake pedal stroke simulators cooperatively, the applicaition complexity of the cooperative regenerative braking system can be significantly dcreased. Models of the vehicle, the tyre, and the main components related to the regenerative brake and the frictional blending brake of the electric passenger car are built. The coordination regenerative management strategy cooperating regeneration efficiency, brake pedal feel, and vehicle jerk, are developed. The proposed regenerative brake system with control strategy has the capability to handle the conflict between regeneration efficiency and brake comfort. The mechanical-electro-hydraulic coupling models of a solenoid valve are built. A linear relationship between limited pressure difference and coil current of an on/off valve in its critical closed state is proposed and illustrated. Then, a novel pressure-difference-limiting modulation method of the hydraulic pressure is developed. It widens the existing hydraulic modulation approaches, and has a great capability to improve the control accuracy of the hydraulic brake pressure during regenerative decelerations. An electric powertrain model with nonlinear backlash and axle flexibility is developed. The effects of the powertrain backlash and the flexibility on the control performance of the blending brake are analyzed. Then, an observer for reconstructing the states of the electric powertrain are designed using hybrid systems approach. Targeting the non-linear backlash and the axle flexibility, a mode-switching-based active compensating algorithm is developed. The proposed algorithm can damp the torsional oscillations of the electric powertrain during regenerative braking, significantly enhancing the blended braking performance.
