针对常用混合动力汽车(Hybrid electric vehicle, HEV)中锂离子电池在功率波动较大时难以满足需求,以及单个驱动周期内HEV燃油能耗大且能量不能很好回收等问题,研究采用锂离子电池和超级电容器混合储能系统(Lithium-ion battery and sup...针对常用混合动力汽车(Hybrid electric vehicle, HEV)中锂离子电池在功率波动较大时难以满足需求,以及单个驱动周期内HEV燃油能耗大且能量不能很好回收等问题,研究采用锂离子电池和超级电容器混合储能系统(Lithium-ion battery and super-capacitor hybrid energy storage system, Li-SC HESS)与内燃机共同驱动HEV运行.结合比例积分粒子群优化算法(Particle swarm optimization-proportion integration, PSO-PI)控制器和Li-SC HESS内部功率限制管理办法,提出一种改进的基于庞特里亚金极小值原理(Pontryagin s minimum principle, PMP)算法的HEV能量优化控制策略,通过ADVISOR软件建立HEV整车仿真模型,验证该方法的有效性与可行性.仿真结果表明,该能量优化控制策略提高了HEV跟踪整车燃油能耗最小轨迹的实时性,节能减排比改进前提高了1.6%~2%,功率波动时减少了锂离子电池的出力,进而改善了混合储能系统性能,对电动汽车关键技术的后续研究意义重大.展开更多
The utilization of traffic information received from intelligent vehicle highway systems(IVHS) to plan velocity and split output power for multi-source vehicles is currently a research hotspot. However, it is an open ...The utilization of traffic information received from intelligent vehicle highway systems(IVHS) to plan velocity and split output power for multi-source vehicles is currently a research hotspot. However, it is an open issue to plan vehicle velocity and distribute output power between different supply units simultaneously due to the strongly coupling characteristic of the velocity planning and the power distribution. To address this issue, a flexible predictive power-split control strategy based on IVHS is proposed for electric vehicles(EVs) equipped with battery-supercapacitor system(BSS). Unlike hierarchical strategies to plan vehicle velocity and distribute output power separately, a monolayer model predictive control(MPC) method is employed to optimize them online at the same time. Firstly, a flexible velocity planning strategy is designed based on the signal phase and time(SPAT) information received from IVHS and then the Pontryagin’s minimum principle(PMP) is adopted to formulate the optimal control problem of the BSS. Then, the flexible velocity planning strategy and the optimal control problem of BSS are embedded into an MPC framework, which is online solved using the shooting method in a fashion of receding horizon. Simulation results verify that the proposed strategy achieves a superior performance compared with the hierarchical strategy in terms of transportation efficiency, battery capacity loss, energy consumption and computation time.展开更多
Excellent student’s academic performance is the uppermost priority and goal of educators and facilitators.The dubious marginal rate between admission and graduation rates unveils the rates of dropout and withdrawal f...Excellent student’s academic performance is the uppermost priority and goal of educators and facilitators.The dubious marginal rate between admission and graduation rates unveils the rates of dropout and withdrawal from school.To improve the academic performance of students,we optimize the performance indices to the dynamics describing the academic performance in the form of nonlinear system ODE.We established the uniform boundedness of the model and the existence and uniqueness result.The independence and interdependence equilibria were found to be locally and globally asymptotically stable.The optimal control analysis was carried out,and lastly,numerical simulation was run to visualize the impact of the performance index in optimizing academic performance.展开更多
文摘为解决燃料电池混合动力公交车中基于优化的能量管理策略难以实车应用的问题,在分析燃料电池公交车(Fuel cell hybrid bus,FCHB)行驶路线的固定性和片段性的基础上,提出了一种基于SOM-K-means(Self-organized mapping K-means)工况识别的能量管理策略。首先,根据公交车站点将行驶路线划分为多个行驶片段,在车辆停站时,运用SOM-K-means二阶聚类模型完成工况识别,获取车辆下一行驶片段的识别协态变量;当车辆在下一个行驶片段运行时,运用识别协态变量完成基于庞特里亚金极值原理(Pontryagin s maximum principle,PMP)求解的能量管理策略的实时应用。其次,建立基于公交车实际运行数据的仿真实验,最后建立硬件在环实验,将所提出的策略移植入整车控制器(Vehicle control unit,VCU)中进行实验。实验结果表明,与基于规则的能量管理策略相比,本研究提出的能量管理策略降低了19.77%的平均等效氢气消耗。且该策略在VCU中每一步的计算时间大约为30 ms,计算结果与仿真结果完全一致,满足车辆对能量管理策略的时效性和准确性的要求。
基金supported by the National Natural Science Foundation of China (62173303)the Fundamental Research for the Zhejiang P rovincial Universities (RF-C2020003)。
文摘The utilization of traffic information received from intelligent vehicle highway systems(IVHS) to plan velocity and split output power for multi-source vehicles is currently a research hotspot. However, it is an open issue to plan vehicle velocity and distribute output power between different supply units simultaneously due to the strongly coupling characteristic of the velocity planning and the power distribution. To address this issue, a flexible predictive power-split control strategy based on IVHS is proposed for electric vehicles(EVs) equipped with battery-supercapacitor system(BSS). Unlike hierarchical strategies to plan vehicle velocity and distribute output power separately, a monolayer model predictive control(MPC) method is employed to optimize them online at the same time. Firstly, a flexible velocity planning strategy is designed based on the signal phase and time(SPAT) information received from IVHS and then the Pontryagin’s minimum principle(PMP) is adopted to formulate the optimal control problem of the BSS. Then, the flexible velocity planning strategy and the optimal control problem of BSS are embedded into an MPC framework, which is online solved using the shooting method in a fashion of receding horizon. Simulation results verify that the proposed strategy achieves a superior performance compared with the hierarchical strategy in terms of transportation efficiency, battery capacity loss, energy consumption and computation time.
文摘Excellent student’s academic performance is the uppermost priority and goal of educators and facilitators.The dubious marginal rate between admission and graduation rates unveils the rates of dropout and withdrawal from school.To improve the academic performance of students,we optimize the performance indices to the dynamics describing the academic performance in the form of nonlinear system ODE.We established the uniform boundedness of the model and the existence and uniqueness result.The independence and interdependence equilibria were found to be locally and globally asymptotically stable.The optimal control analysis was carried out,and lastly,numerical simulation was run to visualize the impact of the performance index in optimizing academic performance.
基金Project supported by the National Natural Science Foundation of China(No.51475414)the Science Fund for Creative Research Groups of National Natural Science Foundation of China(No.51521064)