Operating mode analysis of hybrid AC/DC microgrids

This paper presents a typical topology considering the line parameters of hybrid AC/DC microgrids. There are four basic operation modes of hybrid AC/DC microgrids, such as AC/DC grid-connected mode, AC grid-connected and DC off-grid mode, AC/DC both off-grid mode and AC/DC off-grid respectively mode. And then the power balance relationship of various operating modes was analyzed. According to the number of circuit breaker need to change when the system switch its operation mode, the relationship of the operation mode is divided into two categories, such as Type I and Type II. To reduce the impact on the system and improve system stability, we proposed three principles of operating mode switching and took its mathematical qualitative analysis and simulation validation. The simulation results show that the switching principle does improve the stability of the system to a certain extent and provides some reference for the application development of AC/DC microgrid. (paper)