基于CCIs/VSGs混合的分布式发电系统研究

Research on Distributed Power Generation System Based on Hybrid CCIs/VSGs

针对现有电流源并网逆变器与弱电网之间的交互稳定性以及新能源高渗透率带来的系统低惯量问题,提出在单一电流源逆变器系统中加入一定比例的虚拟同步机(VSG)运行。分别对混合系统中加入电压源型和电流源型VSG的容量占比与短路比(SCR)稳定域的关系进行了研究,加入电压源型VSG的系统SCR稳定域随VSG容量增大而增大,而加入电流源型VSG的系统SCR稳定域随VSG容量增大而减小。由此提出在单一电流源逆变器系统中加入一定比例双模式VSG,以实现混合系统一定的惯量储备及全SCR范围稳定运行。

In view of the interaction stability between the current source grid-connected inverter and the weak power grid and the low inertia of the system caused by the high permeability of new energy,a certain proportion of virtual synchronous generator(VSG) is added to the single current source inverter system.The relationship between capacity ratio and short circuit ratio(SCR) stability region of the hybrid system with voltage source and current source VSG is studied,the SCR stability domain of a voltage source VSG increases with the increase of the capacity of the VSG, the SCR stability domain of the current source VSG decreases with the increase of the capacity of the VSG.Therefore,a certain proportion of dual mode VSG is added into the single current source inverter system to realize certain inertia reserve and stable operation of the whole SCR range of the hybrid system.