基于Pareto的电池容量衰退权衡优化控制策略

Pareto-based optimal control strategy for battery capacity decline

  • 摘要: 由于插电式混合动力汽车电池可以通过电网获取比较廉价的电量,传统的控制策略只考虑充分利用电池电量,但忽略了过度使用电池,会加快动力电池容量的衰退。因此,如何权衡充分利用电池电量与抑制电池容量衰退是新的研究重点。基于电池的半经验衰退模型,引入电池利用程度因子,建立权衡电池容量衰退的能量管理策略。通过Pareto非劣目标域选取合适的权重因子,将多目标优化问题转化为单目标问题,采用动态规划算法获得权重系数全局最优解,通过权衡不同权重下的油耗和电池容量衰退程度选择最优权重系数。在燃油消耗相当的情况下,当权重系数为0.9时,可有效抑制电池寿命的衰减速度。最后,通过在线等效油耗最小策略仿真与在同一权重下的动态规划解进行比较来验证其有效性。

     

    Abstract: As environmental problems become increasingly severe, achieving qualitative breakthroughs in the energy consumption and emissions of traditional internal combustion engine vehicles is difficult. In contrast, new energy vehicles are environmentally friendly and have low fuel consumption, which is important for the future development of vehicles. A plug-in hybrid electric vehicle (PHEV) is widely regarded as the most promising alternative solution for improving energy efficiency and reducing emissions. The optimization of the energy management strategy (EMS) mainly focuses on reducing fuel consumption and improving the economy. However, the durability of the power battery also needs attention, as the lack of life remains a major obstacle to the large-scale commercialization of PHEVs. Because PHEV batteries can obtain relatively cheap power through the grid, the traditional control strategy only considers the full use of the battery power but ignores its excessive use, which will accelerate the decline of the power battery capacity. Therefore, determining how to make full use of the battery power and control the decline of the battery capacity is a new research focus. Based on the semiempirical decay model of the battery, the energy management strategy of balancing the degradation of the battery capacity was established by introducing the battery utilization degree factor. The multiobjective optimization problem was transformed into a single-objective problem by selecting the appropriate weight factor through the Pareto noninferior target domain. A dynamic programming algorithm was used to obtain the global optimal solution of the weight coefficient. The optimal weight coefficient was selected by weighing the fuel consumption and battery capacity decline degree under different weights. In the case of equivalent fuel consumption, the decay rate of battery life can be effectively inhibited when the weight coefficient is 0.9. Finally, the validity of the proposed solution is verified by comparing the online equivalent consumption minimization strategy (ECMS) simulation with the dynamic programming solution under the same weight.

     

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