Magnetic Integration With Controllable Leakage Inductance and Unbalanced Current Suppression for CF DAB Converter Based on Single EE Core

A magnetic integrated structure based on single EE core (SEEC) is proposed to integrate all magnetic elements in current-fed dual active bridge (CF DAB) converter to improve power density. Different from previous works, all magnetic components of CF DAB, including two DC inductors, a transformer and a leakage inductance, are integrated in a SEEC. Moreover, the parameters of inductances and turns ratio can be accurately controlled by designing the number of winding turns and the air gap length. Furthermore, the unbalanced current suppression performance of the two interleaved DC inductors for CF DAB is improved due to the natural negative coupling between the two outer leg windings of the SEEC. In addition, based on the SEEC structure, a SEEC DAB converter is derived. Finally, the validity of the proposed solutions is verified by simulated results from Maxwell finite element analysis (FEA) and experimental results from a 1-kW laboratory prototype. Compared with CF DAB, the power density and efficiency are improved by 71% and 2.14%, respectively.