Fast Response Dual Active Bridge Converter with Elimination of Transient DC Offset By Intermediate Asymmetric Modulation

Dual active bridge converters are attractive solution for bidirectional power conversion, but suffers from transient performance as load changes result in slower dissipation of dc offset produced in inductor and magnetizing current. Additionally, with dc offsets in magnetizing current, core saturation and high peak current may occur when repetitive load transients are applied. In this work, an asymmetric modulation scheme is proposed and its theoretical and simulated transient analysis is carried out. Additionally, zero average current control is proposed which eliminates the dc offset in both inductor and magnetizing current. Theoretical results were verified in PSIM simulation. Experimental verification has also been provided using a 100W prototype. The digital logic of the proposed asymmetric modulation has been implemented in an FPGA controller for experimental verification.