Three-Phase DVR using a Single-Phase Structure with Combined Hysteresis/Dead-band Control

This paper proposes a dynamic voltage restorer for low or medium power applications with a single phase inverter (or STATCOM to acts as a series active filter) structure to compensate the line voltage unbalancing and distortions on the three phase load. The number of required switches of the conventional series three phase circuits is reduced from six to four. A new and simple control routine is applied to eliminate requirements for fast data samplers. In addition a new combined hysteresis/dead-band control with fixed time steps is used to proper charging of batteries (or capacitors) and minimizes energy transferring between line power and batteries by optimum reference voltage estimation, between the standard limits. A circuit model has been simulated with PSCAD/EMTDC software and the results are presented which verify the analysis