Modified triple active bridge DC/AC three phase converter with a series resonant LC circuit on the AC side
A novel three port, isolated, and single stage DC/AC three phase converter is proposed. This converter aims at interfacing a renewable energy source, a battery pack, and the three phase electric grid. The battery and grid ports have bidirectional power flow capability. It is comprised of three active bridges, a HF AC link three winding transformer, and a series resonant LC circuit in the AC port. In contrast to the conventional three port series resonant converter, this structure only includes one LC tank, which makes it more reliable and less complex. The proposed modulation consists in phase shift control under a high and fixed switching frequency. Duty ratio depending of the grid phase is introduced on the AC side. An extra phase angle is added to control real and reactive power transfer. This topology can be considered as the superposition of a DAB DC/DC and a series resonant DC/AC three phase converter. As a result, the currents flowing through the transformer's windings are quasi sinusoidal and trapezoidal waves, which permits low rms and peak current magnitudes. Steady state analysis, design procedure, and simulation results are presented for a 1kW converter.
2017 IEEE Southern Power Electronics Conference (SPEC)