Non-Isolated Single-Phase Trans-Z-Source Converter for Dynamic Voltage Restorer Application

A dynamic voltage restorer (DVR) based on Z-source converter is proposed in this paper. The modified Z-source converter used for the proposed DVR has features such as common ground between input and output, buck out-of-phase operation mode and buck/boost in-phase operation mode. The most important feature that distinguishes the proposed DVR from its counterparts is the ability to buck in-phase that make it possible to compensate for voltage sag under 50% without extra switches. The proposed Z-source converter has a coupled inductor. Therefore, in addition to the duty cycle by adjusting the turn ratio, the desired voltage is generated at the output. As a result, the proposed DVR can compensate for voltage sag and swell in a wide range. The Z-source converter is studied in various operation modes to calculate its voltage gain. The simulation results of the proposed DVR are presented to confirm its performance in PSCAD software.