电动汽车复合储能系统设计及其能量管理方法研究

发布时间：2018-03-29 09:04

本文选题：电动汽车　切入点：复合储能　出处：《浙江大学》2015年硕士论文

【摘要】：随着环境污染和能源短缺等问题的日益凸显,很多国家提出了节能减排等相关政策。电动汽车作为新能源汽车的一种,受到了人们的广泛关注。然而电动汽车中锂电池等动力电池功率密度小,循环使用寿命短,难以满足频繁启动,加速和制动等大电流充放电的行驶场合,削弱了整车的动态性能。而超级电容功率密度大且循环使用寿命长,因此将二者有机结合组成的复合储能系统能有效提升电动汽车的综合性能。本文主要工作包含以下几个方面： 1、针对复合储能系统的特点,分别从系统架构、基本模块、系统控制等三方面对复合储能系统进行了分析。通过归纳比较储能元件接入直流母线方式,总结双向DC-DC变流器拓扑和控制,对比不同的系统控制策略优劣后,介绍了层次控制的模块化复合储能系统的总体设计思路。 2、分析隔离型双向DC-DC变流器启动时冲击电流的产生机理。在此基础上,设计了两种软启动的优化控制方法：变占空比软启动和变移相角软启动。两种控制策略在不添加额外的辅助电路情况下,有效地降低了冲击电流的幅值,保证变流器的安全启动。文中对两种控制策略的工作原理进行了详细的公式推导和分析比较,并结合仿真和实验对两种软启动策略进行了验证。 3、针对复合储能系统的能量管理,设计了双下垂分频协调控制策略。一方面,通过电压级联控制实现了超级电容和储能电池对功率波动的分频响应,实现二者优势互补；另一方面,在传统的下垂控制中引入SOC的反馈控制,形成了对变流模块输出电流和储能电池荷电状态的双下垂协调控制。使得在确保传统下垂控制均流特性的前提下,根据储能电池荷电状态(SOC)对储能电池模块输出功率加以自适应调整,达到合理的负荷分配,有效避免储能电池的过充过放运行,提高电池组的使用寿命。
[Abstract]:With the increasing problems of environmental pollution and energy shortage, many countries have put forward energy saving and emission reduction policies. Electric vehicles as a kind of new energy vehicles, However, the power density of lithium-ion battery in electric vehicle is small, the cycle life is short, and it is difficult to meet the high current charge and discharge driving situation, such as frequent startup, acceleration and braking, etc. It weakens the dynamic performance of the whole car. And the super capacitor has high power density and long cycle life. Therefore, the composite energy storage system can effectively improve the comprehensive performance of electric vehicles. The main work of this paper includes the following aspects:. 1. According to the characteristics of composite energy storage system, the system structure, basic module and system control are analyzed respectively. After summarizing the topology and control of bi-directional DC-DC converter and comparing the advantages and disadvantages of different system control strategies, the overall design idea of modular composite energy storage system with hierarchical control is introduced. 2. The mechanism of impulse current generation during startup of isolated bidirectional DC-DC converter is analyzed. Two optimal control methods for soft start are designed: variable duty ratio soft start and variable phase shift soft start. The two control strategies can effectively reduce the amplitude of impulse current without adding additional auxiliary circuit. In this paper, the working principle of the two control strategies is deduced, analyzed and compared in detail, and the two soft start strategies are verified by simulation and experiment. 3. For the energy management of the composite energy storage system, a dual droop frequency division coordinated control strategy is designed. On the one hand, the frequency division response of the super capacitor and the energy storage battery to the power fluctuation is realized by the voltage cascade control, which realizes the complementary advantages between the two. On the other hand, the feedback control of SOC is introduced into the traditional droop control, which forms the dual droop coordination control for the output current of the converter module and the charged state of the energy storage battery. According to the current state of energy storage battery (SOC), the output power of energy storage battery module can be adjusted adaptively to achieve reasonable load distribution, which can effectively avoid overcharging and overdischarge operation of energy storage battery and improve the service life of battery pack.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U469.72;TM46

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