Survey of inverter topologies implemented in dynamic voltage restorers

Voltage disturbances which affect the stability of electrical networks are the most important power quality problems. The most known voltage disturbances are voltage sag and swell in distribution systems. Dynamic Voltage Restorer (DVR) is the most effective device to compensate these voltage disturbances among the custom power devices. The basic structure of a conventional DVR consists of an inverter, dc link capacitor, injection transformer and filter. The major component in DVR is inverter that generates controlled voltage to compensate voltage sag/swell and other problems such as flicker, interruption and harmonics. Each inverter implemented in DVR has individual properties such as voltage level, unbalanced compensation capability and/or dc link capacitor requirement. This paper aims a comprehensive review on different inverter topologies according to the number of phases, size, voltage level and structure of DVR. In addition, individual properties of inverters are presented in this study.