The DVR-AC, a novel structure for mitigating large voltage sags and swells using voltage re-injection

Voltage sags, swells and harmonic distortion are three of the more representative PQ events in distribution grids. For mitigating such events various AC-AC- and AC-link structures has been proposed over the years with greater or lesser success for ameliorating large voltage deviation events. This paper introduces the DVR-AC (Dynamic Voltage Restorer Alternate Current), a novel power electronics-based structures alternative option for mitigating short and long standing voltage swell and sags with large magnitude deviations from nominal. The solution is based upon an AC input 2×2 matrix converter whose output voltage is injected to the grid through a series transformer. The magnitude control of the injected voltage, based on PWM, is clearly explained. The cases of study results evidence the advantages of the DVR-AC respective to other techniques and topologies.