Large-Signal Stability Analysis and Control for Small-Scale AC Microgrids With Single Storage

Small-signal stability studies of ac microgrids have obtained abundant results, however, the large-signal stability is still a great challenge and this topic is little studied. In this article, the nonlinear reduced-order model of small-scale ac microgrids with single storage is established considering the structure changes of converters under large disturbances. Then, the large-signal stability is analyzed and the unstable mechanism is revealed. It is found that the structural changes caused by the limitation links have a great influence on the system stability. Based on the unstable mechanism, the virtual synchronous damping control is proposed to enhance the large-signal stability of ac microgrids. The effectiveness of the proposed analysis and control methods is validated through related case studies.