Single Stage Dual Active Bridge AC-DC Converter with Active Power Decoupling

The paper introduces a new a isolated DC-AC DAB converter topology, capable of active power decoupling on the AC side of the transformer, made up of two full bridges with no additional active component. The differential voltage modulated by the DC-side full bridge is used to control the voltage applied to the primary winding of a high-frequency transformer, while the common mode voltage generated by the AC-side full bridge is applied to the secondary windings. The choice of applying the common mode voltage ripple of the AC-side full bridge to the transformer, allows to have the required ripple voltage to transfer the power, while keeping the differential voltage ripple, that is applied to the AC output, at its minimum value, making possible the use of a small AC filter inductor. A control strategy is proposed and validated by simulation. This work is being developed at University of Nottingham within the framework of project SENSIBLE.