摘要
基于虚拟同步发电机(virtual synchronous generator,VSG)控制的光储单元可用于组建独立微网,并为微网稳定运行提供有力支撑。但由于分布式电源输出存在波动性和间歇性的问题,在长期运行过程中,功率供需不平衡将会导致储能设备的荷电状态超过安全运行范围。针对该问题,将根据荷电状态调整下垂系数的方法拓展到VSG控制之中。通过分析发现,改变下垂系数难以有效实现控制目标,且可能造成系统失稳。通过引入自适应下垂特性的概念,使用平移下垂特性的方法对VSG控制做了进一步改进,改进后的VSG控制减少了对系统稳定性的影响,更有利于实现有功功率的合理分配与荷电状态的快速调整。通过Matlab/Simulink工具搭建了仿真模型,对相关分析和所提策略进行了系统仿真和方法验证。
The photovoltaic-energy storage unit, based on virtual synchronous generator （VSG） control, can be used to form island microgrid, and provide forceful support for the stable operation of microgrid. However, the imbalance between power consumption and generation in the cycle of running, will get the state of charge （SOC） of energy storage equipment beyond its safe operation region, due to the fluctuation and intermittent of distributed generator output. According to this issue, the method of adjusting droop coefficient according to SOC is introduced into the VSG control. Through analysis, it is found that it may be difficult to achieve the control target by changing the droop coefficient. During the regulating process, the system can even lose its stability. By introducing the concept of adaptive droop characteristic, further improvement of VSG control is made by translating the whole droop characteristic. The improved VSG control reduces the impact on system stability. The reasonable allocation of active power and the fast adjustment of SOC can be realized more effectively. Relevant theoretical analysis and proposed scheme are verified by the simulation system built with Matlab/Simulink simulation tool.
出处
《电力建设》
北大核心
2016年第9期115-122,共8页
Electric Power Construction
基金
国家自然科学基金项目(51177047)
河北省科技计划项目(16214504D)~~
关键词
虚拟同步发电机
下垂特性
光伏微网
自适应控制
超级电容器
virtual synchronous generator
droop characteristic
photovoltaic microgrid
adaptive control
supercapacitor
