摘要
为了解决基于传统下垂控制的并联微网逆变器输出功率分配不合理问题,以两逆变器并联运行模型为研究对象,详细分析下垂控制中并联逆变器输出功率分配机理,得出并联逆变器输出功率分配不精确的本质原因是逆变器总输出阻抗和额定容量间的不匹配。进而提出了一种改进下垂控制策略,在电压外环采用准比例谐振(PR)控制,同时虚拟阻抗被引入到电流反馈环,进而使逆变器总输出阻抗近似于虚拟阻抗,通过比例设置虚拟阻抗实现并联逆变器输出功率的精确分配&此外,在功率控制环中引入逆变器输出电压幅值反馈环节,合理选定预设电压,有效改善了虚拟阻抗造成的输出电压降低问题。仿真软件验证了理论分析的正确性。
In order to solve the problem of unreasonable output power distribution of parallel micro-grid inverters under traditional droop control,this paper takes parallel operation model of two inverters as the research object,the detailed analysis of the output power distribution mechanism of parallel inverters in droop control is conducted,and the essential reason for inaccurate output power distribution of parallel inverters is the mismatch between the total output impedance of the inverter and the rated capacity.Therefore,an improved droop control strategy is proposed to solve this problem.The quasi-proportional resonance (PR) control is applied to the outer voltage loop,and the virtual impedance is introduced into the current feedback loop,so that the total output impedance of the inverter is similar to the virtual impedance,thus achieving accurate distribution of output power of parallel inverters by setting virtual impedance according to capacity ratio.In addition,the inverter output voltage amplitude feedback loop is introduced into the power control loop and the predetermined voltage is selected properly,which can effectively improve the output voltage reduction caused by the virtual impedance.The correctness of the theoretical analysis is verified by simulation software.
作者
常振东
陶彩霞
Chang Zhendong;Tao Caixia(School of Automation & Electrical Engineering,Lanzhou Jiao Tong University,Lanzhou 730070,China)
出处
《电测与仪表》
北大核心
2019年第11期75-80,107,共7页
Electrical Measurement & Instrumentation
基金
国家重点研发计划资助项目(2017YFB1201003-020)
国家自然科学基金资助项目(51767015)
甘肃省自然科学基金资助项目(1610RJZA051)
关键词
功率分配
准比例谐振控制
虚拟阻抗
预设电压
power distribution
quasi proportion resonant control
virtual impedance
preset voltage
