摘要
网侧功率变换器是变频驱动系统接入配电网的重要接口,随着变频驱动系统渗透率的不断提高,网侧功率变换器对配电网中的影响越发突出。借鉴传统电力系统中的同步发电机数学模型,形成电网接口虚拟同步发电机控制方案,设计具有变频驱动系统自身特性的虚拟调速器和虚拟励磁控制器,保证电网电流的低谐波畸变的同时,满足负荷功率需求,并具有响应电网电压/频率异常事件功能,可在一定程度上提高电网的稳定性。同时模拟同步发电机的转动惯量,提高电网接口的惯性和阻尼,降低变频驱动系统对电网的影响,提升电网对大规模变频驱动系统接入的适应性。为实现电网接口的柔性起动,提出一种虚拟同步预并网控制方法,可实现电网接口柔性离/并网切换,消除起动冲击电流。仿真和实验结果表明了所提控制方案的有效性。
The grid-side power converter is an import interface to access the distribution network for variable frequency drive systems. With the increasing penetration of variable frequency drive systems,the impact of the grid-side power converter on the distribution network becomes much more important. Firstly the virtual synchronous generator control scheme is formed in accordance with the synchronous generator model of traditional power systems, while the virtual speed controller and the virtual excitation controller are designed with the characteristics of variable frequency drive systems,which ensures low harmonic distortion of grid current as well as meets the load＇s power need. The system can also respond to the abnormal grid voltage / frequency,which can improve the stability of the grid to a certain degree. Meanwhile,simulating the moment inertia of the synchronous generator can improve the inertia and damping of the grid interface and reduce the impact of variable frequency drive systems on the grid,and thus enhance the adaptability of the grid during the large-scale variable frequency drive system access. To achieve the flexible start of the grid interface,a virtual synchronization pre-connection control method is proposed,which can realize the flexible on / off switching of the grid and eliminate the inrush current. The simulation and experimental results show the effectiveness of the proposed control scheme.
出处
《电工技术学报》
EI
CSCD
北大核心
2015年第23期83-92,共10页
Transactions of China Electrotechnical Society
关键词
变频驱动
电网接口
虚拟同步发电机
柔性启动
Variable frequency drive
grid interface
virtual synchronous generator
flexible start
