纯电动拖拉机复合供电系统自适应能量管理与容量配置

    Adaptive energy management and capacity configuration for electric tractor power supply system

    • 摘要: 针对电动拖拉机续航能力不足、电源系统放电随机性大导致能耗高及容量配置不完善等问题,该研究设计了基于蓄电池和超级电容供电的复合供电系统。针对动态负载适应性差的问题设计了三段式功率负载控制规则,建立了功率划分参数与负载统计量之间的函数关系。针对传统固定阈值策略下电动拖拉机作业工况变化导致储能系统放电效果差的现象,在双闭环控制的基础上提出了基于模糊逻辑的放电阈值自适应调整策略。此外,考虑到蓄电池和超级电容在功率密度、能量密度和价格方面的差异性,提出考虑节能率和综合经济效应最优的混合储能系统容量配置策略。构建包含储能装置全寿命周期成本和系统耗电费用容量配置目标函数,分别对无阈值控制策略与本文阈值控制策略的节能率进行分析,利用遗传算法对容量配置目标函数进行寻优求解,并分析节能率约束条件对容量配置结果的影响。对所提放电阈值自适应调整策略进行仿真分析,并在实验室10 kW负载供电模拟系统进行试验验证。结果表明:本文模糊逻辑自适应阈值控制策略的节能率比无阈值的传统能量管理策略提升了3.09%,每小时耗电费用减少近9.5%,供电系统在功率波动较大时输出电压为527 V,在功率平稳时输出电压为520 V,提高了复合供电系统输出电压稳定性,所提策略能以较低的计算成本实现较好的实时能量管理。

       

      Abstract: This paper designed a composite power supply system to solve the problems of insufficient endurance of electric tractors, high energy consumption due to high randomness of power system discharge and imperfect capacity configuration, the study designed a composite power supply system based on battery and supercapacitor power supply. Aiming at the problem of poor dynamic load adaptability, a three-stage load power segmentation rule was designed, and the functional relationship between the power division parameter and the load statistics was established. Aiming at the phenomenon of poor discharging effect of the energy storage system due to changes in the working conditions of the electric tractor under the traditional fixed-threshold strategy, a fuzzy logic-based adaptive adjustment strategy for the discharging threshold was proposed on the basis of double closed-loop control. In addition, considering the differences between storage batteries and supercapacitors in terms of power density, energy density and price, a hybrid energy storage system capacity configuration method that considered the optimal energy saving rate and comprehensive economic effect was proposed. The capacity configuration objective function containing the whole life cycle cost of the energy storage device and the system power consumption cost was constructed, the energy saving rate results of the no-threshold control strategy and the threshold control strategy in this paper were analyzed separately, the genetic algorithm was used to find the optimal solution for the capacity configuration objective function, and the impact of the energy saving rate constraints on the capacity configuration results was analyzed. In addition, the proposed discharge threshold adaptive adjustment strategy was simulated and analyzed, and the simulation test was completed on the laboratory 10 kW load power supply simulation system to verify. The results showed that the energy saving rate using the fuzzy logic adaptive threshold control strategy in this paper was improved by 3.09% and the hourly power consumption was reduced by nearly 9.5% compared with the traditional energy management strategy without threshold, at the same time, the output voltage of the power supply system was 527 V when the power fluctuated greatly and the output voltage of the power supply system was 520 V when the power fluctuates was smooth, which improved the output voltage stability of the energy storage system. Implementation of the designed energy management strategy for composite power supply system using genetic algorithm can achieve better real-time energy management with lower computational cost.

       

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