Abstract
Multi module isolated converters (MMICs) find extensive
application in various DC-DC applications due to their remarkable
features of galvanic isolation, bi-directional power flow, high power
density and enhanced efficiency. However, voltage and current sharing
among the converter modules are the most significant issues in MMICs.
This paper proposes Multi-port Integrated-Magnetics Transformers
(MpIMTs) which address the input-output DC-link voltage imbalances
within an ISOS converter. The proposed transformers ensure the input
voltage sharing (IVS) and output voltage sharing (OVS) through balancing
windings within their structures, thus substitutes the complicated
active control scheme with the balancing winding. Besides, the input
side and output side modules are decoupled from each other, thus the
impact of parameters variation and inter-module energy transfer during a
transient of one side does not reflect to the other side. These
properties are achieved by proposing a custom-designed core and an off
the shelf available U core assembled MpIMTs. The magnetic and electrical
equivalent along with the design criteria of the balancing winding are
also presented. Furthermore, the paper includes the comparative analysis
of the proposed transformers which reveals that while the U-core MpIMT
offers simplified construction, it comes at the expense of slightly
reduced efficiency compared to the custom-designed MpIMT. Finally, the
proposed U core MpIMT is validated through a laboratory prototype.