The inconsistency of the cells in a battery pack can affect its lifespan,safety and reliability in the electric vehicles. The balanced system is an effective technique to reduce its inconsistency and improve the opera...The inconsistency of the cells in a battery pack can affect its lifespan,safety and reliability in the electric vehicles. The balanced system is an effective technique to reduce its inconsistency and improve the operating performance. A hybrid equilibrium strategy based on decision combing battery state-of-charge( SOC) and voltage has been proposed. The battery SOC is estimated through an improved least squares method. An equalization hardware in loop( HIL) platform has been constructed. Based on this HIL platform,equilibrium strategy has been verified under the constant-current-constant-voltage( CCCV) and dynamicstresstest( DST) conditions. Experimental results indicate that the proposed hybrid equalization strategy can achieve good balance effect and avoid the overcharge and over-discharge of the battery pack at the same time.展开更多
In order to solve the problems of high temperature and inconsistency in the operation of electric vehicle( EV) battery pack,computational fluid dynamics( CFD) simulation method is used to simulate and optimize the...In order to solve the problems of high temperature and inconsistency in the operation of electric vehicle( EV) battery pack,computational fluid dynamics( CFD) simulation method is used to simulate and optimize the heat dissipation of battery pack. The heat generation rate at different discharge magnifications is identified by establishing the heat generation model of the battery. In the forced air cooling mode,the Fluent software is used to compare the effects of different inlet and outlet directions,inlet angles,outlet angles,outlet sizes and inlet air speeds on heat dissipation. The simulation results show that the heat dissipation effect of the structure with the inlet and outlet on the same side is better than that on the different sides; the appropriate inlet angle and outlet width can improve the uniformity of temperature field; the increase of the inlet speed can improve the heat dissipation effect significantly. Compared with the steady temperature field of the initial structure,the average temperature after structure optimization is reduced by 4. 8℃ and the temperature difference is reduced by 15. 8℃,so that the battery can work under reasonable temperature and temperature difference.展开更多
为解决传统均衡电拓扑均衡效率较低的问题,文中提出了一种两级均衡拓扑结构。该均衡拓扑将电池组分为组内与组间两种形式,组内采用Buck-Boost均衡电路,组间采用可重构均衡电路,组内与组间可同时均衡,提高了均衡效率。以SOC(State of Cha...为解决传统均衡电拓扑均衡效率较低的问题,文中提出了一种两级均衡拓扑结构。该均衡拓扑将电池组分为组内与组间两种形式,组内采用Buck-Boost均衡电路,组间采用可重构均衡电路,组内与组间可同时均衡,提高了均衡效率。以SOC(State of Charge)作为均衡变量,组内均衡算法采用基于SOC的模糊逻辑控制策略,减少均衡时间,提高均衡效率。使用MATLAB/Simulink软件对电路拓扑建模仿真,并与传统Buck-Boost电路进行对比。仿真结果表明,在充放电状态下,相较于传统Buck-Boost电路,所提算法及均衡拓扑使均衡时间减少了约28%,表明该均衡电路及算法具有良好的性能。展开更多
The increasing gross weight of electric Unmanned Aerial Vehicle(UAV) poses a challenge in practical applications. The range and endurance of the electric UAV are limited by the fixed mass of the battery package. In th...The increasing gross weight of electric Unmanned Aerial Vehicle(UAV) poses a challenge in practical applications. The range and endurance of the electric UAV are limited by the fixed mass of the battery package. In this work, a design optimization method for the battery package topology of small electric UAV is proposed to enhance the performance. To improve the accuracy of the method, the dynamic battery model and simplified electric component models are presented.These models are utilized by the trajectory optimization method, which takes the dynamic characteristic into consideration to calculate the aircraft performance. The direct optimal control method is used for solving the trajectory optimization problem, and this method is tested on a small blended-wing-body electric aircraft. The test result shows that the range and energy-consumption are mainly influenced by the parallel topology of the battery package, while the flight time in climb phase is more sensitive to the series topology. It is deduced that the range-and energy-optimal design points can be considered concurrently in design optimization. The work proves the feasibility of integrating the trajectory optimization and battery package design.展开更多
基金Supported by the National Natural Science Foundation of China(51507012)Beijing Nova Program(Z171100001117063)
文摘The inconsistency of the cells in a battery pack can affect its lifespan,safety and reliability in the electric vehicles. The balanced system is an effective technique to reduce its inconsistency and improve the operating performance. A hybrid equilibrium strategy based on decision combing battery state-of-charge( SOC) and voltage has been proposed. The battery SOC is estimated through an improved least squares method. An equalization hardware in loop( HIL) platform has been constructed. Based on this HIL platform,equilibrium strategy has been verified under the constant-current-constant-voltage( CCCV) and dynamicstresstest( DST) conditions. Experimental results indicate that the proposed hybrid equalization strategy can achieve good balance effect and avoid the overcharge and over-discharge of the battery pack at the same time.
基金Supported by the National Natural Science Foundation of China(51507012)Beijing Nova Program(Z171100001117063)
文摘In order to solve the problems of high temperature and inconsistency in the operation of electric vehicle( EV) battery pack,computational fluid dynamics( CFD) simulation method is used to simulate and optimize the heat dissipation of battery pack. The heat generation rate at different discharge magnifications is identified by establishing the heat generation model of the battery. In the forced air cooling mode,the Fluent software is used to compare the effects of different inlet and outlet directions,inlet angles,outlet angles,outlet sizes and inlet air speeds on heat dissipation. The simulation results show that the heat dissipation effect of the structure with the inlet and outlet on the same side is better than that on the different sides; the appropriate inlet angle and outlet width can improve the uniformity of temperature field; the increase of the inlet speed can improve the heat dissipation effect significantly. Compared with the steady temperature field of the initial structure,the average temperature after structure optimization is reduced by 4. 8℃ and the temperature difference is reduced by 15. 8℃,so that the battery can work under reasonable temperature and temperature difference.
文摘为解决传统均衡电拓扑均衡效率较低的问题,文中提出了一种两级均衡拓扑结构。该均衡拓扑将电池组分为组内与组间两种形式,组内采用Buck-Boost均衡电路,组间采用可重构均衡电路,组内与组间可同时均衡,提高了均衡效率。以SOC(State of Charge)作为均衡变量,组内均衡算法采用基于SOC的模糊逻辑控制策略,减少均衡时间,提高均衡效率。使用MATLAB/Simulink软件对电路拓扑建模仿真,并与传统Buck-Boost电路进行对比。仿真结果表明,在充放电状态下,相较于传统Buck-Boost电路,所提算法及均衡拓扑使均衡时间减少了约28%,表明该均衡电路及算法具有良好的性能。
基金China Scholarship Council for the support during his study and research。
文摘The increasing gross weight of electric Unmanned Aerial Vehicle(UAV) poses a challenge in practical applications. The range and endurance of the electric UAV are limited by the fixed mass of the battery package. In this work, a design optimization method for the battery package topology of small electric UAV is proposed to enhance the performance. To improve the accuracy of the method, the dynamic battery model and simplified electric component models are presented.These models are utilized by the trajectory optimization method, which takes the dynamic characteristic into consideration to calculate the aircraft performance. The direct optimal control method is used for solving the trajectory optimization problem, and this method is tested on a small blended-wing-body electric aircraft. The test result shows that the range and energy-consumption are mainly influenced by the parallel topology of the battery package, while the flight time in climb phase is more sensitive to the series topology. It is deduced that the range-and energy-optimal design points can be considered concurrently in design optimization. The work proves the feasibility of integrating the trajectory optimization and battery package design.