A three-leg AC voltage regulator with fictitious DC-link

A three-leg AC voltage regulator with a fictitious dc-link is proposed. The proposed scheme combines a rectifier with an inverter in a stage. Hence, the proposed voltage regulator not only reduces the number of main switches but also decreases the cost. A small AC capacitor is used, which makes it possible to replace an electrolytic capacitor with a film capacitor, not only the size of the dc link capacitor can be reduced, but also the lifetime of the voltage regulator can be increased. Furthermore, the proposed scheme can also compensate the voltage disturbance like under-voltage, over-voltage, voltage sag, and voltage swell effectively. Finally, some simulation results are provided to demonstrate the performance of the proposed three-leg AC voltage regulator with a fictitious dc-link.