A Soft-Switching Single-Phase Two-Arm Dynamic Voltage Restorer

This paper presents a soft-switching single-phase two-arm dynamic voltage restorer (DVR) which can solve the voltage disturbance problems such as voltage sag, voltage swell, undervoltage and over-voltage. The proposed scheme is composed of a two-arm topology which operates as a rectifier and an inverter. Rather than the conventional four-arm topology, the proposed two-arm topology not only reduces the number of main switches but also increases the system reliability and simplifies the control circuits. 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.