A Dual Active Bridge Converter with an Extended High-Efficiency Range by DC Blocking Capacitor Voltage Control

A Dual Active Bridge Converter with an Extended High-Efficiency Range by DC Blocking Capacitor Voltage Control

Qin, Z. (TU Delft DC systems, Energy conversion & Storage)
Shen, Yanfeng (Aalborg University)
Loh, Poh Chiang (The Chinese University of Hong Kong)
Wang, Huai (Aalborg University)
Blaabjerg, Frede (Aalborg University)

2018

A Dual Active Bridge (DAB) converter can achieve a wide high-efficiency range when its input and output voltages are equal, assuming a 1:1 turns ratio for its isolation transformer. If its input or output voltage is doubled, efficiency of the DAB will drop significantly, because of the introduction of hard switching and high circulating power. Thus, a new modulation scheme has been proposed, whose main idea is to introduce a voltage offset across the dc blocking capacitor connected in series with the transformer. Operational principle of the proposed modulation has been introduced, before analyzing its soft-switching area and circulating power mathematically. The final modulation scheme is not difficult to implement, but can help the DAB achieve soft switching, low circulating power, and thereby high efficiency, even with its input or output voltage doubled.
These features have been verified by experimental results obtained with a 1.2 kW prototype.

dual active bridge
modulation
high efficiency
soft switching
circulating power

http://resolver.tudelft.nl/uuid:87796e61-7687-4c5d-901b-3e239a3d0131

https://doi.org/10.1109/TPEL.2017.2746518

0885-8993

IEEE Transactions on Power Electronics, 33 (7), 5949-5966

Accepted Author Manuscript

Institutional Repository

journal article

© 2018 Z. Qin, Yanfeng Shen, Poh Chiang Loh, Huai Wang, Frede Blaabjerg