A Dynamic Voltage Restorer Equipped With a High-Frequency Isolated DC–DC Converter

This paper presents a dynamic voltage restorer (DVR) that is characterized by the use of a high-frequency unidirectional isolated dc-dc converter. A traditional DVR has a large and bulky series transformer even for three-phase low-voltage up to 480-V applications because the transformer operates at the line frequency (50 or 60 Hz). The emergence of state-of-the-art semiconductor devices and magnetic cores has driven power electronic engineers to develop compact high-frequency isolated dc-dc converters. This paper discusses the control and performance of a low-voltage DVR using a high-frequency isolated dc-dc converter. The high-frequency (20-kHz) transformer in the dc-dc converter is much smaller, for example, one-hundredth, in volume than the line-frequency transformer. Moreover, connecting the shunt converter to the load side brings a significant reduction in energy-storage capacity to the DVR. Experimental results obtained from a three-phase three-wire 200-V 5-kW laboratory system confirm the viability and effectiveness of the system configuration.