直流微电网蓄电池功率均衡及母线电压稳定控制研究

发布时间：2018-06-26 00:26

本文选题：直流微电网 + 蓄电池储能装置　；参考：《西安理工大学》2017年硕士论文

【摘要】：近年来,直流微电网得到了极大关注和迅速发展,成为接纳光伏等分布式可再生能源的良好方式。储能装置作为直流微电网中必不可少的组成部分和关键支撑技术,其高效利用和有效管理,对平抑可再生能源发电及负荷的波动、稳定直流母线电压、提升整个直流微电网的电能质量和供电可靠性具有重要的作用。针对直流微电网中集中式蓄电池储能装置因荷电状态(State of Charge,SOC)及接口变换器差异等造成的功率分配不均问题,提出一种基于SOC不平衡度的功率分配控制策略。引入SOC不平衡度算法并构建SOC不平衡度对角矩阵,通过SOC不平衡度阈值判断蓄电池储能装置均衡状态并获取合理的功率分配指令。仿真和实验结果表明该方法能够有效控制集中式蓄电池储能装置实现功率均衡分配。研究适用于直流微电网分布式蓄电池储能装置的功率动态自均衡控制策略,提出一种基于储能SOC的改进下垂控制方法,通过引入的SOC不平衡度算法动态调节下垂系数,控制各蓄电池储能装置的SOC及输出功率达到动态均衡;采用传统母线电压二次控制方法补偿下垂控制引起的直流母线电压跌落,维持直流母线电压的稳定。仿真和实验结果验证了该控制方法的正确性和有效性。为解决光伏等可再生能源及负荷造成的直流母线电压波动问题,针对储能接口变换器,引入虚拟直流电机(Virtual DC Machine, VDCM)控制策略。探究VDCM及其改进控制策略的工作机理及稳定直流母线电压的原理,建立VDCM控制系统的小信号模型分析控制参数对系统稳定性的影响;与传统双闭环恒压控制进行对比研究,探讨VDCM控制策略对提升光储负载直流微电网母线电压稳定性的作用。仿真和实验结果表明VDCM控制策略具有惯性和阻尼特性,能够增强直流微电网的惯性和阻尼,有效缓冲和抑制功率波动对直流母线电压的影响,提升直流母线电压的稳定性。
[Abstract]:In recent years, DC microgrid has received great attention and rapid development, and has become a good way to accept distributed renewable energy such as photovoltaic. As an essential part and key supporting technology of DC microgrid, energy storage device can effectively utilize and manage the power generation and load fluctuation of renewable energy, and stabilize DC bus voltage. Improving the power quality and reliability of the whole DC microgrid plays an important role. A power allocation control strategy based on the unbalance of SOC is proposed to solve the problem of uneven power distribution caused by the difference between the state of charge (SOC) and the interface converter in the centralized storage battery in DC microgrid. The unbalance degree algorithm of SOC is introduced and the diagonal matrix of unbalance degree of SOC is constructed. Through the threshold of unbalance degree of SOC, the equilibrium state of storage battery device is judged and the reasonable power distribution instruction is obtained. Simulation and experimental results show that this method can effectively control the centralized storage battery energy storage device to achieve power distribution. The power dynamic self-equalization control strategy for distributed storage battery in DC microgrid is studied. An improved droop control method based on SOC is proposed, and the droop coefficient is dynamically adjusted by the introduced SOC unbalance algorithm. The SOC and output power of each battery storage device are controlled to achieve dynamic equalization, and the traditional bus voltage secondary control method is used to compensate the DC bus voltage drop caused by sag control to maintain the stability of DC bus voltage. Simulation and experimental results show that the proposed control method is correct and effective. In order to solve the voltage fluctuation of DC bus caused by renewable energy sources such as photovoltaic and load, a virtual DC machine (VDCM) control strategy is introduced for the energy storage interface converter. This paper probes into the working mechanism of VDCM and its improved control strategy and the principle of stabilizing DC bus voltage, establishes the small signal model of VDCM control system to analyze the influence of control parameters on the stability of the system, and compares it with the traditional double closed loop constant voltage control. This paper discusses the effect of VDCM control strategy on improving voltage stability of DC microgrid with optical storage load. Simulation and experimental results show that VDCM control strategy has inertia and damping characteristics, can enhance the inertia and damping of DC microgrid, effectively buffer and suppress the influence of power fluctuation on DC bus voltage, and improve the stability of DC bus voltage.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM727;TM912

【参考文献】