DC dynamic voltage restorer (DC-DYR): A new concept for voltage regulation in DC systems

Many of the sensitive and high power loads in the AC distribution power system are direct current (DC) loads, which power quality is a fundamental issue in this type of load. There are many factors that affect the issue of power quality. The voltage sag is one of them which is the main factor in reducing power quality of grid. There are many of devices to increase voltage quality in the grid. The dynamic voltage restorer (DVR) is an economical solution to eliminate voltage-related power quality problems. In this paper, a DC dynamic voltage restorer (DC-DVR) is presented to retrieve the voltage drop at sensitive DC loads in the AC power grids. The proposed DC-DVR receives energy from output of the rectifier to maintain the load voltage constant at a nominal value. The proposed DC-DVR is in fact an isolated DC-DC converter fed from the DC bus and its output is series connected to the DC bus. The performance of the proposed DC-DVR is verified via simulations in PLECS software.