In recent years, the increasing penetration of distributed generation in microgrids challenges the control and coordination of energy resources. Especially in microgrids with virtual synchronous generator (VSG)-controlled converters and conventional synchronous generators (SG), the inherent inertia difference (i.e., the VSG and SG) results in a poor transient performance when the VSG and/or loads are cut in/out. Thus, this paper explores the transient performance of microgrids with parallel VSG and SG systems. More importantly, a novel pre-synchronization control method is proposed to eliminate the phase jump while meeting the requirements in case of closures or re-closures of generation units. A small-signal dynamic model is presented, and accordingly, the VSG inertia and its damping can be designed considering the capacity ratio of VSG and SG units. In addition, with the power angle stability analysis, an active power provision strategy is introduced to suppress the transient power oscillation due to the inertia difference. Finally, the feasibility of the proposed methods is verified by simulations on a microgrid consisting of parallel VSG and SG units.

中文翻译：

---

具有并联同步发电机和虚拟同步发电机的微电网暂态分析

近年来，分布式发电在微电网中的日益普及对能源资源的控制和协调提出了挑战。特别是在具有虚拟同步发电机 (VSG) 控制的转换器和传统同步发电机 (SG) 的微电网中，当 VSG 和/或负载切入时，固有的惯性差异​​（即 VSG 和 SG）会导致较差的瞬态性能。出去。因此，本文探讨了具有并联 VSG 和 SG 系统的微电网的瞬态性能。更重要的是，提出了一种新的预同步控制方法，在满足发电机组关闭或重新关闭的情况下消除相位跳跃的同时满足要求。提出了一个小信号动态模型，因此，考虑 VSG 和 SG 单元的容量比，可以设计 VSG 惯性及其阻尼。此外，通过功率角稳定性分析，引入有功功率提供策略，抑制惯性差异引起的暂态功率振荡。最后，通过对由并联 VSG 和 SG 单元组成的微电网进行仿真验证了所提出方法的可行性。