Design and Implementation of a Low-cost Back-to-back Dynamic Voltage Restorer

Design and Implementation of a Low-cost Back-to-back Dynamic Voltage Restorer

The dynamic voltage restorer (DVR) is a power converter-based device widely used in power distribution systems toimprove voltage quality. A conventional DVR includes an energy storage device (ESD) to provide the required power for alimited duration of voltage sag. However, the employment of ESD increases the DVR costs and limits its functionality. Thisresearch paper investigated a single-phase back-to-back DVR with simulation and small-scale hardware implementation. Theproposed DVR includes two inverters connected in series and parallel with the distribution system, respectively, to enablebidirectional power flow. The advantage of this topology is its ability to compensate for longer voltage sags and swells, thusachieving a low-cost design. Using digital control scheme, the proposed DVR is able to perform multiple control functionssimultaneously, 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 andthe proposed control scheme. Also, two sets of simulation studies and hardware tests were performed to do so. The typical resultsderived from the software simulation and small-scale hardware implementation are provided to verify the effectiveness of theproposed DVR and the related control scheme.