Analysis of a dynamic voltage compensator with reduced switch-count and absence of energy storage system

The utilization of dynamic voltage restorers to protect sensitive loads against short-term voltage disturbances has been proven to be a competitive solution in medium- and high-power applications. For low-power applications further cost reductions are required to make the technology even more competitive, although just a few numbers of studies have already been conducted in this area. This paper discusses the design and operation of a three-phase dynamic voltage compensator, including control strategies for the converters. The proposed topology and control strategies are evaluated through simulation studies based on measured data, selected by the IEEE Power Quality Task Force for the characterization of power quality events and device performance evaluation, along with disturbances recorded in a steel plant, in Minas Gerais State, Brazil. An experimental implementation of the compensator is developed to allow a better evaluation of specific and critical operating modes, such as the forced commutation of the bypass thyristors and inverter operation.