DC Bias Abatement in Dual Active Bridge Converter using Covalent Active and Passive Components

The Dual Active Bridge (DAB) converter is the most attractive bidirectional DC-DC converter topology in the distribution network. However, the DC bias is the most common issue in the dual active bridge converter due to the sudden change in internal or external phase shift angles to regulate the power signal. Consequently, it will increase conduction losses, a core saturation problem of High-Frequency Transformer (HFT), and loss of Zero Voltage Switching (ZVS) operation. Therefore, this paper presents the DC bias abatement in the DAB converter using covalent active and passive components to alleviate these problems. The proposed method employs the series capacitor in the windings of HFT as the passive component. Whereas the DAB converter's control variables are used as the active component, which modulates the power signal. Thus, the detailed control strategy along with covalent active and passive components to mitigate the DC bias problem is presented in this paper. The experiential results validate the performance of the proposed control method in terms of wide-range of voltage regulation and soft-switching operations.