Comparison of system topologies for dynamic voltage restorers

In this paper, different system topologies for dynamic voltage restorers are analyzed with the emphasis put on methods to acquire the necessary energy during a voltage sag. Four different system topologies are analyzed and tested. Two, which can be realized with insignificant energy storage and the energy is taken from the grid and two topologies, which are based on stored energy are compared. Experimental tests on a 10 kVA rated dynamic voltage restorer shows that the no-energy storage concept is feasible, but an improved performance can for certain voltage sags, be achieved with stored energy. In the comparison, the no-storage topology with a passive shunt converter at the load side is ranked highest followed by an energy storage topology with constant DC-link voltage.