Quad-Port AC–DC–DC–AC Operation of Isolated Dual Three-Phase Active Bridge Converter

This paper investigates the operation of the Dual Three-Phase Active Bridge (D3AB) converter topology as a multi-port converter, by taking the three-phase ac port and dc port on the primary side (ac
1
and dc
1
) and the galvanically isolated three-phase ac port and dc port on the secondary side (ac
2
and dc
2
) simultaneously into account. The basic working principle of the D3AB topology under multi-port operation and a strategy to achieve independent power transfer between the four ports are described. It is found that the realization of a power transfer between ac
1
and ac
2
, which can be operated with different line voltages and line frequencies, is particularly challenging, as compared to dc
1
–dc
2
operation. Therefore, this mode of operation is further analyzed and suitable modulation schemes are developed to achieve sinusoidal ac currents, constant dc-link voltages, and reduced low-frequency power pulsations between the ac ports. The derived analytical results are verified by means of circuit simulations and experiments, for a primary-side ac rms phase voltage of 115 V and line frequency of 50 Hz, a secondary-side ac rms phase voltage of 57.5 V and line frequency of 77 Hz, and an output power of 675 W.