基于模糊综合评价体系的动力电池组均衡方法研究

发布时间：2018-05-17 11:04

本文选题：模糊综合评价体系 + 灰色关联度理论　；参考：《合肥工业大学》2017年硕士论文

【摘要】：在近年来的研究和应用中,电池均衡技术取得了长足进展,然而各类均衡技术在均衡速度、均衡效率、均衡成本、充放电时间、扩展性能、均衡实时性、均衡精确性、电池组寿命影响程度、均衡实现性等方面的表现参差不一,寻求最优电池组均衡方案具有现实意义。本文将均衡拓扑类型优选作为研究出发点,从多评价角度对均衡拓扑类型进行评判。然后将该优选方法运用到SOC的估算算法筛选之中优选出最优估算算法,并在所优选出的均衡拓扑类型基础上,通过改进其对应的传统均衡算法和搭建最简均衡拓扑结构,进一步提高均衡方案的综合性能。首先,构建基于模糊理论建立了均衡拓扑类型综合评价体系,包括评价指标的提取和评价指标集数学模型、评价指标权重求解模型、隶属度函数以及综合评价函数的建立。其中:(1)从分析均衡拓扑类型所对应的传统均衡算法入手,得出均衡拓扑类型对串联电池组均衡效果的主要影响因素,进而提取均衡拓扑类型评价指标。(2)基于灰色关联度理论,利用六位专家打分对评价指标权重进行求解,增强权重选取的有效性。(3)依据均衡拓扑类型在各评价指标中的优劣程度排序结果及隶属度分辨率确立评价指标隶属度函数,保证隶属度函数的合理性。其次,从“软件”的角度提升均衡方案的综合性能。该部分包括两个方面:(1)利用均衡拓扑综合评价体系中所蕴含的信息对传统均衡算法进行改进,将传统的“削峰”和“填谷”均衡算法相结合建立一种新型“削峰填谷”均衡算法。(2)将均衡拓扑综合评价体系应用于SOC估算算法的优选之中,制定了基于锂离子单体电池一阶RC改进模型的扩展卡尔曼滤波算法SOC估算算法。再次,以结构简单、操作性能好、操作能耗低作为切入点,进行均衡硬件系统设计,从“硬件”的角度提高均衡方案的整体性能。该部分包含三个方面:(1)运用图论和排列组合的知识列举出优选的均衡拓扑类型对应的所有均衡拓扑结构,利用多绕组变压器可以简化连接关系这一特性确立均衡拓扑最简结构。(2)利用mosfet通态内阻远低于肖基二极管和mosfet体二极管的特性,通过同步整流操作方式降低均衡过程中的能量损耗。(3)利用单周期控制技术使得均衡输入电流恒定,提高均衡可控性。最后,将制定的均衡策略导入到均衡硬件系统之中,并对串联电池组进行均衡实验,结果表明本方案可行且高效。
[Abstract]:In recent years, great progress has been made in the research and application of battery equalization technology. However, all kinds of equalization techniques have made great progress in equalization speed, equalization efficiency, equalization cost, charge / discharge time, extended performance, equalization real time, equalization accuracy, etc. The performance of battery life influence degree, equalization realization is different, so it is of practical significance to seek the optimal battery pack equalization scheme. In this paper, the optimal selection of equilibrium topological types is taken as the starting point of the research, and the equilibrium topological types are judged from the point of view of multiple evaluation. Then the optimal selection method is applied to the selection of SOC estimation algorithm, and based on the selected optimal topology type, the corresponding traditional equalization algorithm is improved and the minimal equilibrium topology structure is built. Further improve the comprehensive performance of the equalization scheme. Firstly, a comprehensive evaluation system of equilibrium topological types based on fuzzy theory is established, which includes the extraction of evaluation indexes, the mathematical model of evaluation index set, the calculation model of evaluation index weight, the membership function and the establishment of comprehensive evaluation function. (1) starting from the analysis of the traditional equalization algorithm corresponding to the equilibrium topology type, the main influencing factors of the equilibrium topology type on the equalization effect of the series battery pack are obtained, and then the evaluation index of the equilibrium topology type is extracted, which is based on the grey correlation degree theory. The evaluation index weight is solved by six experts, and the validity of weight selection is enhanced. The membership function of evaluation index is established according to the ranking result of the degree of equilibrium topology type in each evaluation index and the resolution of membership degree. The rationality of membership function is guaranteed. Secondly, from the point of view of software, the comprehensive performance of the equalization scheme is improved. This part includes two aspects: 1) the traditional equalization algorithm is improved by using the information contained in the comprehensive evaluation system of equilibrium topology. A new "peak cutting and valley" equalization algorithm is established by combining the traditional "peak cutting" and "valley filling" equalization algorithms. (2) the comprehensive evaluation system of equilibrium topology is applied to the optimal selection of SOC estimation algorithm. An extended Kalman filter (SOC) estimation algorithm based on the improved first order RC model of lithium ion cell is developed. Thirdly, with simple structure, good operation performance and low operating energy consumption, the balanced hardware system is designed to improve the overall performance of the equalization scheme from the point of view of "hardware". This section contains three aspects: 1) using graph theory and permutation and combination knowledge to enumerate all the equilibrium topologies corresponding to the selected equilibrium topological types. Using the characteristics of multi-winding transformer to simplify the connection relationship, the simplest structure of equalization topology can be established.) the on-state internal resistance of mosfet is much lower than that of Schottky diode and mosfet bulk diode. The single period control technique is used to make the equalization input current constant and the equalization controllability is improved by using synchronous rectifier operation to reduce the energy loss in the equalization process. Finally, the proposed equalization strategy is introduced into the equalization hardware system, and the equalization experiment of the series battery pack is carried out. The results show that this scheme is feasible and efficient.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM912

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