Single-Phase Dynamic Voltage Restorer Based on AC-AC Trans-Z-Source Converter for Voltage Sag and Swell Mitigation

In this paper, a new single-phase single-stage dynamic voltage restorer (DVR) based on AC-AC trans-Z-source converter is proposed. The proposed DVR is connected directly to the grid and the energy required for compensation is provided by it. Therefore, there is no need for large energy storage elements such as DC-link. A coupled inductor is employed in impedance network of the proposed DVR to compensate deep voltage sags. The safe commutation strategy used in the Z-source converter ensures that any voltage and current spikes occur on the switches. The analysis of the Z-source converter circuit and the performance of the proposed DVR are given. To verify the performance and capability of the proposed system, the simulation results are presented in the PSCAD/EMTDC software.