A soft-switching single-phase three-arm dynamic voltage restorer

This paper presents a soft-switching single-phase three-arm dynamic voltage restorer which aimed at solving voltage disturbances such as voltage swell, voltage sag, over-voltage and under-voltage. The proposed scheme is composed of a three-arm topology which operates as a rectifier and an inverter. Rather than the conventional four-arm topology, the proposed three-arm topology not only reduces the number of main switches but also increases the system reliability and simplifies the control circuits. Moreover, using simple resonant units, all main switches of high-frequency arm are operated at zero-voltage-switching (ZVS) turn-on, while all auxiliary switches are operated at zero-current-switching (ZCS) turn-off. Finally, some simulation results are presented for verification.