ABSTRACT

 The Dynamic Voltage Restorer (DVR) is a power converter-based device widely used in power distribution systems to improve voltage quality. A conventional DVR includes an energy storage device (ESD) to provide the required power for a limited duration of voltage sag. However, the employment of ESD increases the DVR costs and limits its functionality. This research paper investigated a single-phase back-to-back DVR with simulation and small-scale hardware implementation. The proposed DVR includes two inverters connected in series and parallel with the distribution system, respectively, to enable bidirectional power flow. The advantage of this topology is its ability to compensate for longer voltage sags and swells, thus achieving a low-cost design. Using digital control scheme, the proposed DVR is able to perform multiple control functions simultaneously, including voltage swell/sag compensation, power factor correction (PFC), and harmonic current compensation. Based on the aforesaid, this paper reviews the related literature on DVR and then introduces the working principles of DVR and the proposed control scheme. Also, two sets of simulation studies and hardware tests were performed to do so. The typical results derived from the software simulation and small-scale hardware implementation are provided to verify the effectiveness of the proposed DVR and the related control scheme. Keywords: Dynamic Voltage Restorer (DVR); power quality control; back-to-back converter; digital controller.