基于线路电阻观测值的直流微电网改进下垂控制策略研究  

An improved droop control strategy for a DC microgrid based on line resistance observations

作　　者：宁显华 潘欢[1,2] 李峰 吴嘉欣[1] NING Xianhua;PAN Huan;LI Feng;WU Jiaxin(School of Electronic and Electrical Engineering,Ningxia University,Yinchuan 750021,China;Ningxia Key Laboratory of Electrical Energy Security,Yinchuan 750004,China)

机构地区：[1]宁夏大学电子与电气工程学院,宁夏银川750021 [2]宁夏电力能源安全重点实验室,宁夏银川750004

出　　处：《电力系统保护与控制》2024年第11期42-51,共10页Power System Protection and Control

基　　金：国家自然科学基金项目资助(61763040,52167006);宁夏自然科学基金项目资助(2022AAC05001);中科院“西部之光”人才培养计划项目资助。

摘　　要：负载功率精确均分和母线电压稳定是直流微电网的主要控制目标,但传统下垂控制会引起电流分配精度低和母线电压偏差大。针对此问题,提出一种基于线路电阻观测值的改进下垂控制策略。线路电阻不匹配是导致各变换器输出电流不均分的主要原因。首先使用递推最小二乘法对线路电阻进行估计,利用估计得到的线路电阻值调整下垂系数。再进一步考虑到每个变换器的额定功率各不相同,根据变换器的额定功率调整下垂系数,实现各变换器输出电流按其额定功率比例分配。最后在Matlab/Simulink平台搭建孤岛直流微电网模型,对3种不同下垂系数进行仿真,并在恒定负载、变负载、变换器退出运行3种工况下,验证了所提下垂控制在功率均分和稳压方面的有效性和可行性。Accurate load power equalization and bus voltage stabilization are the main control objectives of DC microgrids.However,traditional droop control causes problems of low current distribution accuracy and significant bus voltage deviation.An improved droop control strategy based on line resistance observations is proposed to solve this shortcoming.The main reason for the uneven distribution of the output current of each converter is the mismatch of line resistance.The line resistance is first estimated using the recursive least squares method.The droop coefficient is adjusted using the estimated line resistance value.Then further considering that the rated power of each converter is different,the droop coefficient is adjusted according to the rated power of the converter so that the output current of each converter is distributed in proportion to its rated power.Finally,an islanded DC microgrid model is constructed on the Matlab/Simulink platform,and three different droop coefficients are simulated to verify the effectiveness and feasibility of the method for power equalization and voltage stabilization under the operating conditions of constant and variable load,and converter withdrawal.

关 键 词：直流微电网 下垂控制 递归最小二乘法 线路电阻 额定功率 

分 类 号：TM721.1[电气工程—电力系统及自动化]