True three-phase bidirectional switch based AC-AC Buck-Boost converter topology

A new three-phase true bidirectional switch is proposed in this paper. This switch consist of a unidirectional switch enclosed in two three phase diode bridges with bidirectional input and output terminals. A family of simple topologies of three-phase AC-AC converters using the true bidirectional switch is possible as direct extension of DC-DC converters having similar operating principle. Steady state analysis and simulation results are presented in this paper using the Buck-Boost topology as an example. Performance of the circuit has been found satisfactory with duty cycle variation. The proposed converter can be used for AC-AC line conditioning to overcome voltage sags, surges, and load fluctuations. Because the proposed converters employ only two active devices, they can reduce cost and complexity and improve system reliability.