A Three Phase Voltage Restorer Based on Bipolar Direct AC/AC Converters

A new topology is proposed to regulate voltage sags/swells in the distribution network in this paper. Voltage sags and swells are a serious power quality problem faced by the power industry. Based on energy storage devices, the major traditional voltage restorer is not adequate for compensating deep and long-duration voltage sags/swells. To solve this problem, a novel bipolar direct AC/AC type voltage restorer (AC/AC-VR) topology is proposed, with bipolar regulation ability and no storage device. The restorer of each phase is connected to the other two phases and the power is tapped from them. By controlling the duty cycle of each AC/AC converter, the required voltage is realized to maintain stability. Analysis, simulation, and experimental results are presented to demonstrate the proposed topology.