Stability study on dynamic voltage restorer (DVR)

This paper discusses the stability study in dynamic voltage restorer (DVR), a series compensation device mainly used to mitigate voltage sags. Based on the appropriate modeling of the DVR system, the detailed stability analysis of the DVR system is performed. This research work is an attempt to obtain mathematical interactions between the DVR and linear loads. In this paper, theoretical study of different linear load effects on the system stability will be proposed and analyzed, in which the stable operation range of the DVR is investigated. Moreover, a significant reduction of inverter gain in the situation of over-modulation can strongly affect the system stability. The results of simulation are presented to validate the load stability analysis and over-modulation effect to the inverter gain, a key parameter affecting the system stability.