Most researches focus on the regenerative braking system design in vehicle components control and braking torque distribution,few combine the connected vehicle technologies into braking velocity planning.If the brakin...Most researches focus on the regenerative braking system design in vehicle components control and braking torque distribution,few combine the connected vehicle technologies into braking velocity planning.If the braking intention is accessed by the vehicle-to-everything communication,the electric vehicles(EVs)could plan the braking velocity for recovering more vehicle kinetic energy.Therefore,this paper presents an energy-optimal braking strategy(EOBS)to improve the energy efficiency of EVs with the consideration of shared braking intention.First,a double-layer control scheme is formulated.In the upper-layer,an energy-optimal braking problem with accessed braking intention is formulated and solved by the distance-based dynamic programming algorithm,which could derive the energy-optimal braking trajectory.In the lower-layer,the nonlinear time-varying vehicle longitudinal dynamics is transformed to the linear time-varying system,then an efficient model predictive controller is designed and solved by quadratic programming algorithm to track the original energy-optimal braking trajectory while ensuring braking comfort and safety.Several simulations are conducted by jointing MATLAB and CarSim,the results demonstrated the proposed EOBS achieves prominent regeneration energy improvement than the regular constant deceleration braking strategy.Finally,the energy-optimal braking mechanism of EVs is investigated based on the analysis of braking deceleration,battery charging power,and motor efficiency,which could be a guide to real-time control.展开更多
Braking energy recovery(BER)aims to recover the vehicle's kinetic energy by coordinating the motor and mechanical braking torque to extend the driving range of the electric vehicle(EV).To achieve this goal,the mot...Braking energy recovery(BER)aims to recover the vehicle's kinetic energy by coordinating the motor and mechanical braking torque to extend the driving range of the electric vehicle(EV).To achieve this goal,the motor/generator mode requires frequent switching and prolonged operation during driving.In this case,the motor temperature will unavoidably rise,potentially triggering motor thermal protection(MTP).Activating MTP increases the risk of motor component failure,and the EV typically disables the BER function.Thus,maximizing BER while reducing the risk of motor overheating is a challenging problem.To address this issue,this article proposes a predictive BER strategy with MTP using the non-smooth Pontryagin Minimum Principle(NSPMP)for EVs.Firstly,a Markov long short-term memory(MLSTM)model is designed to obtain future velocity information.Secondly,the BER problem with MTP in the studied EV is embedded in a model predictive control(MPC)framework.Then,under the MPC framework,the NSPMP strategy is proposed to resolve the problem of MTP.Finally,the performance of the proposed strategy is verified through simulation and a hardware-in-loop test.The results show that in two real-world driving cycles,compared to the rule-based strategy,the proposed strategy reduced power consumption by 1.24%and0.96%,respectively,and effectively limited motor temperature.Additionally,under global cycle conditions,this strategy demonstrated better MTP control performance compared to other benchmark strategies.展开更多
The system presented in this paper allows the direct transfer of kinetic energy of a vehicle’s motion to a flywheel and vice-versa. For braking, a cable winds onto a pulley geared to the vehicle’s propulsion drivesh...The system presented in this paper allows the direct transfer of kinetic energy of a vehicle’s motion to a flywheel and vice-versa. For braking, a cable winds onto a pulley geared to the vehicle’s propulsion driveshaft as it unwinds from another pulley geared to the flywheel and then operates in reverse for the transfer of energy in the opposite direction. The cable windings are in one plane resulting in an effective pulley radius that increases when the cable is winding onto it and decreases when unwinding from it. Thus, an increasing driven-to-driving pulley velocity ratio is obtained during a period of energy transfer in either direction. A dynamic analysis simulating the process was developed. Its application is illustrated with a numerical solution based on specific assumed values of system parameters.展开更多
Braking of the urban vehicles of public service wastes a large number of engine energy in the condition of starting and stopping frequently. Aiming at the problem, an electro-mechanical braking energy regeneration sys...Braking of the urban vehicles of public service wastes a large number of engine energy in the condition of starting and stopping frequently. Aiming at the problem, an electro-mechanical braking energy regeneration system was proposed which adopted a high-speed flywheel and a battery to recover the braking energy and achieve the secondary traction for the auxiliary start function. The system strategy was designed and the braking simulation was processed to validate its feasibility. The experiment results show that the system can effectively recover the braking energy, improve the starting performance of the city bus and it can be applied to the engineering.展开更多
为进一步提高制动能量回收率,考虑不同工况下驾驶员不同制动意图所需的制动效果,提出了一种四驱电动汽车制动控制策略。首先,针对常规制动工况,基于常规制动意图识别,从制动能量回收率、稳定性和安全性角度分别设计控制策略;其次,针对...为进一步提高制动能量回收率,考虑不同工况下驾驶员不同制动意图所需的制动效果,提出了一种四驱电动汽车制动控制策略。首先,针对常规制动工况,基于常规制动意图识别,从制动能量回收率、稳定性和安全性角度分别设计控制策略;其次,针对滑行工况下的不同滑行制动意图,判断电机制动力是否介入及何时介入,并根据驾驶员所需的滑行距离计算电机制动力的大小;然后,由台架试验获得前后电机外特性并建立前后电机最优利用效率模型;最后,利用Carsim和Simulink进行了联合仿真分析。仿真结果表明,在新欧洲驾驶循环(New European Driving Cycle,NEDC)工况下,与并联控制策略相比,能量回收率提升了13.64百分点;在滑行工况下可有效识别驾驶员需求滑行距离,提升了整车滑行经济性。展开更多
针对纯电动商用车在连续制动时,气源压力偏低会导致驱动轴耦合制动力响应速度变慢,影响制动能量回收效率的问题,提出一种基于比例继动阀的解耦式制动能量回收系统(uncoupled braking energy recovery system,URBS)方案。首先,基于比例...针对纯电动商用车在连续制动时,气源压力偏低会导致驱动轴耦合制动力响应速度变慢,影响制动能量回收效率的问题,提出一种基于比例继动阀的解耦式制动能量回收系统(uncoupled braking energy recovery system,URBS)方案。首先,基于比例继动阀的迟滞特性,采用前馈-单神经元PID控制方法,实现制动气压的准确输出;其次,以电池SOC、车速等为约束条件,根据气源压力信号确定供压模式,并制定解耦式制动能量回收控制策略;最后,基于AMESim,MATLAB/Simulink及TruckSim搭建联合仿真平台,选取单次制动工况与循环工况验证了制动力耦合效果及系统的制动能量回收效果。结果表明,基于比例继动阀的URBS可实现耦合制动力的快速响应,达到稳态压力值75%的时间小于0.1 s,且在中国重型商用车行驶工况和中国重型商用车瞬态工况下有效制动能量回收率分别为10.13%,17.17%。所提URBS方案能有效提高驱动轴耦合制动力的响应速度及耦合精度,可为纯电动商用车气压式URBS方案设计提供参考。展开更多
基金Supported by Jiangsu Provincial Key R&D Program(Grant No.BE2019004)National Natural Science Funds for Distinguished Young Scholar of China(Grant No.52025121)+1 种基金National Nature Science Foundation of China(Grant Nos.51805081,51975118,52002066)Jiangsu Provincial Achievement Transformation Project(Grant No.BA2018023).
文摘Most researches focus on the regenerative braking system design in vehicle components control and braking torque distribution,few combine the connected vehicle technologies into braking velocity planning.If the braking intention is accessed by the vehicle-to-everything communication,the electric vehicles(EVs)could plan the braking velocity for recovering more vehicle kinetic energy.Therefore,this paper presents an energy-optimal braking strategy(EOBS)to improve the energy efficiency of EVs with the consideration of shared braking intention.First,a double-layer control scheme is formulated.In the upper-layer,an energy-optimal braking problem with accessed braking intention is formulated and solved by the distance-based dynamic programming algorithm,which could derive the energy-optimal braking trajectory.In the lower-layer,the nonlinear time-varying vehicle longitudinal dynamics is transformed to the linear time-varying system,then an efficient model predictive controller is designed and solved by quadratic programming algorithm to track the original energy-optimal braking trajectory while ensuring braking comfort and safety.Several simulations are conducted by jointing MATLAB and CarSim,the results demonstrated the proposed EOBS achieves prominent regeneration energy improvement than the regular constant deceleration braking strategy.Finally,the energy-optimal braking mechanism of EVs is investigated based on the analysis of braking deceleration,battery charging power,and motor efficiency,which could be a guide to real-time control.
基金supported by the National Natural Science Foundation of China(Grant Nos.52275047,51975048)。
文摘Braking energy recovery(BER)aims to recover the vehicle's kinetic energy by coordinating the motor and mechanical braking torque to extend the driving range of the electric vehicle(EV).To achieve this goal,the motor/generator mode requires frequent switching and prolonged operation during driving.In this case,the motor temperature will unavoidably rise,potentially triggering motor thermal protection(MTP).Activating MTP increases the risk of motor component failure,and the EV typically disables the BER function.Thus,maximizing BER while reducing the risk of motor overheating is a challenging problem.To address this issue,this article proposes a predictive BER strategy with MTP using the non-smooth Pontryagin Minimum Principle(NSPMP)for EVs.Firstly,a Markov long short-term memory(MLSTM)model is designed to obtain future velocity information.Secondly,the BER problem with MTP in the studied EV is embedded in a model predictive control(MPC)framework.Then,under the MPC framework,the NSPMP strategy is proposed to resolve the problem of MTP.Finally,the performance of the proposed strategy is verified through simulation and a hardware-in-loop test.The results show that in two real-world driving cycles,compared to the rule-based strategy,the proposed strategy reduced power consumption by 1.24%and0.96%,respectively,and effectively limited motor temperature.Additionally,under global cycle conditions,this strategy demonstrated better MTP control performance compared to other benchmark strategies.
文摘The system presented in this paper allows the direct transfer of kinetic energy of a vehicle’s motion to a flywheel and vice-versa. For braking, a cable winds onto a pulley geared to the vehicle’s propulsion driveshaft as it unwinds from another pulley geared to the flywheel and then operates in reverse for the transfer of energy in the opposite direction. The cable windings are in one plane resulting in an effective pulley radius that increases when the cable is winding onto it and decreases when unwinding from it. Thus, an increasing driven-to-driving pulley velocity ratio is obtained during a period of energy transfer in either direction. A dynamic analysis simulating the process was developed. Its application is illustrated with a numerical solution based on specific assumed values of system parameters.
基金supported by the Industrialization of Colleges and Universitis in Jiangsu Province Sponsored by Qing Lan Project
文摘Braking of the urban vehicles of public service wastes a large number of engine energy in the condition of starting and stopping frequently. Aiming at the problem, an electro-mechanical braking energy regeneration system was proposed which adopted a high-speed flywheel and a battery to recover the braking energy and achieve the secondary traction for the auxiliary start function. The system strategy was designed and the braking simulation was processed to validate its feasibility. The experiment results show that the system can effectively recover the braking energy, improve the starting performance of the city bus and it can be applied to the engineering.
文摘为进一步提高制动能量回收率,考虑不同工况下驾驶员不同制动意图所需的制动效果,提出了一种四驱电动汽车制动控制策略。首先,针对常规制动工况,基于常规制动意图识别,从制动能量回收率、稳定性和安全性角度分别设计控制策略;其次,针对滑行工况下的不同滑行制动意图,判断电机制动力是否介入及何时介入,并根据驾驶员所需的滑行距离计算电机制动力的大小;然后,由台架试验获得前后电机外特性并建立前后电机最优利用效率模型;最后,利用Carsim和Simulink进行了联合仿真分析。仿真结果表明,在新欧洲驾驶循环(New European Driving Cycle,NEDC)工况下,与并联控制策略相比,能量回收率提升了13.64百分点;在滑行工况下可有效识别驾驶员需求滑行距离,提升了整车滑行经济性。
