基于虚拟同步发电机的微电网改进下垂控制策略

摘要

针对传统下垂控制作用下微电网的运行状态平滑切换问题，利用虚拟同步发电机思想，在控制环中加入虚拟的转动惯量方程，使得微电网逆变器具有与传统的同步发电机相似的动态性能，解决了微电网逆变器输出阻抗小、阻尼小等问题，以此来降低由于功率的急剧变化所造成的频率振荡；同时增加一个补偿控制环节，增加系统在运行状态切换情况下的稳定性。采用 MATLAB 软件进行仿真，验证了所设计的微电网改进下垂控制策略的有效性。%In allusion to smooth switching of operational state of the micro-grid under the role of traditional droop control, virtual moment of inertial equation is added in control loop by adopting thinking of virtual synchronous generator,which makes inverter of the micro-grid have similar dynamic performance with traditional synchronous generator and solves prob-lems of output of the inverter such as small impedance,small damp,and so on. Thus,frequency oscillation caused by sharp change of power is reduced. Meanwhile,a compensation control is added for increasing stability of the system under the con-dition of operational state switching. MATLAB software is used for simulation,which verifies validity of the designed im-proved droop control strategy for micro-grid.