Research And Digital Simulation On Control Technology Of Dynamic Voltage Restorer

The proliferation of voltage sensitive equipment has made industrial processes more vulnerable to supply voltage deviations. Such voltage deviations, commonly in the form of voltage sags, can cause severe process disruptions and result in substantial production loss. DVR is an novel and all-round type of power electronics device base on voltage source Inverter(VSI). DVR is a solid-state dc to ac switching power converter that injects a set of three-phase ac output voltages in series with the incoming distribution voltages such that the sag problem can be effectively solved.In this paper the control technology, detection technology and application problems of DVR are discussed and summarized. I build up DVR's mathematical models, it is shown that the existing load voltage control strategy used in DVR has poor transient performance. Damping will be improved if the proposed mulitloop controller is adopted. The performance improvement of DVR with double closed-loop control strategy is analysed and validated by simulation studies. This paper also discussed the research situation and applications of fault currentlimiters(FCL). The characteristics and technological levels of various kinds of fault current limiting devices are analysed and compared, including their advantage and shortcomings of every sort of FCL.