含同步机微网中基于解耦下垂的自适应虚拟阻抗控制

Adaptive Virtual Impedance Control Based on Decoupling Droop in Microgrid With Synchronous Generators

在微网中,由于下垂控制逆变器的功率爬坡速度快于同步机,逆变器的带载能力受到限制;同时,低压传输环境导致传统下垂功率控制失败,危及系统稳定性。考虑低压微网阻感性传输线路,根据逆变器输出电流的越限情况与中央控制器的调度命令,该文在逆变器解耦下垂控制基础上构造了自适应虚拟阻抗,并据其变化强度调节功角进行协同控制,提高逆变器与同步机的功率均分程度与限流稳定性。最后,通过建立小信号模型分析虚拟阻抗大小对系统输出特性的影响。仿真和实验验证了提出控制策略的有效性。

In microgrid, the output capacity of the droop controlled inverter is undermined parallel with synchronous generator, even the operation of the islanded microgrid is under risk due to its faster output response and low voltage transmission situation. Operating with power angle based on its changing amplitude under resistive induction situation, an adaptive virtual impedance lying on the output current of the inverter and the command from central controller was proposed, which improves the power sharing and the stability between the inverter and synchronous generator. Small-signal analysis was used to set the virtual impedance parameters, and validation was provided by simulation and experimental results.