Isolated Multiport Converter as Cost Efficient Solution for DC-Fast Charger of Electric Vehicle

Abstract

The ongoing electrification of the transport sector raises demands for new power electronic solutions. As a consequence, modular converter structures are state of the art for fast charging, since high power and short charging times are required. This work presents a modular multiport DC-DC converter which has the capability to decrease the cost and size of the required charging station. Furthermore, design guidelines for the investigated topology are presented. The analysis is validated with a three port isolated DC-DC converter with separated loads.

Multidirectional power flow in three-port isolated DC-DC converter for multiple battery stacks

“…The placement of the coupling inductors in TBDC also affects its performance and it has been suggested in the literature [19] that impedance of the output bridge should be larger than that of transformer primary. It has also been suggested that placing external inductors on secondary side yields a better performance than placing on all ports or on the primary alone.…”

“…It has also been suggested that placing external inductors on secondary side yields a better performance than placing on all ports or on the primary alone. The first configuration requires small phase shifts to maintain the two output ports at equal voltages if one port voltage changes due to the variation of the other port voltage [19,20]. (d) Requirement of magnetics: Reduction in the core mean length in TBDC toplogy results in core volume reduction and correspondingly core cost reduction by one-fourth times compared to the conventional system (14).…”

“…(e) Overall cost analysis Figure 5c Scenario-1: Both systems with equal power transfer capability in primary section. In TBDC (TBDC-a), 25% cost reduction in magnetic core occurs, whereas costs of the switch and copper winding are equal (as discussed above) [19,20].…”

“…Such converters help in reduction of overall energy conversion system size and corresponding controllers needed [9]. Various multiple active bridge (MAB) topologies based on converter modularization and cell level modularization have been reported in the literature [10][11][12][13][14][15][16][17][18][19][20]. The topology of three-port isolated bidirectional DC-DC converter (TBDC) is a member of the MAB family.…”

“…With increased implementation complexity, other three methods can improve wide range power control. In the literature, the TBDC topology has been explained and analysis has also been reported [17][18][19][20].…”