A review of AC choppers

AC choppers are a family of ac-to-ac power converters that can be derived from the traditional dc-to-dc converters. Research activity in this kind of converter has recently increased in applications for power conditioning—such as voltage control in the distribution system and power flow control in the transmission system—as an alternative for the dc-link approach compensators based on voltage source converters. The control is simpler and the power rating of the devices is smaller for compensators with the same power rating; the main drawback is they cannot control the output-voltage frequency as the matrix converter. This paper presents a state-of-the-art review on the development of ac-choppers. The principle of operation is explained by using the six switches three-phase buck converter as an example. The main applications used in power conditioning and power flow control are introduced along with emerging topologies.