Dynamic voltage restorer based on fuzzy logic control for voltage sag restoration

Power quality problems such as voltage sags are presently impor tant issues in the industrial field. The dynamic voltage restorer (DVR) is a series compensation device that mitigates voltage sag problems. Due to the nonlinearity of the D VR dynamic character istics, the compensating performance of the D VR is affected much by its control strategy. In this paper, fuzzy logic control is proposed to enhance the compensating performance of the transformer-less D VR. Recently new FL methods have been applied to Custom Pow er Devices, especially for active power filters. The operation of DVR is similar to that of active power filters in that both compensators must respond very fast on the request from abruptly changing ref erence signals. Simulation studies were conducted to show that the proposed fuzzy logic DVR control is very effective in damping the system oscillations and improving the compensating performances compared to the traditional PI control.