A Ring-Connected Dual Active Bridge Based DC-DC Multiport Converter for EV Fast-Charging Stations

Abstract

This paper proposes a multiport DC-DC converter for EV fast-charging stations. The proposed converter is comprised of Ring-Connected Dual Active Bridge (RCDAB) DC-DC converters, where the connection point between every two adjacent DABs provides a DC port. Bypass switches are added to each DAB to eliminate unnecessary power processing stages in the event of idle ports (no EVs) (open circuit ports). The nature of the ring connection of the RCDAB theoretically allows infinite internal power flow solutions within the ring to satisfy a certain power flow scenario at the DC ports, hence, the optimal power flow solution can be selected to minimize total RMS current and losses. Single-phase shift control is applied to this optimization problem to make it simple. A novel closed-loop control scheme using Bisection optimization is developed to minimize the total RMS current. A control-hardware-in-the-loop (CHiL) validation is carried out for a 5-port network of the proposed topology to investigate the converter efficiency and fault tolerance/availability characteristics. Also, an experimental hardware validation is implemented for a 3-port network where different scenarios for power flow and faults are performed. Finally, a comparative discussion between the proposed topology and other multiport topologies in literature is presented revealing the superior performance of the RCDAB topology.INDEX TERMS Dual active bridge (DAB), DC-DC multiport converter, electric vehicle (EV), fast charging, ring-connected DAB (RCDAB), single phase shift (SPS) control.

Multiport DC-DC Converter with Differential Power Processing for Fast EV Charging Stations

“…This is because the reference current at the second port is equal to the string current, I bat.2 = I String , which means that the current supplied by the auxiliary converter connected to port 2, I DAB2 = 0. On the other hand, currents processed by DAB1 and DAB3 are non-zero which imposes ripples at the port current, from Equations ( 9)- (11). Based on the readings illustrated in Figures 12 and 13, the proposed architecture has better system efficiency for same charging power.…”

“…This topology, however, has cascaded conversion, which, in return, impacts efficiency. Furthermore, a ring-connected dual active bridges-based multiport converter is reported in [11], where it offers high redundancy and availability due to existence of two power paths for each port. Another ring topology has been proposed in [12] with PV system integration at each port.…”

A Nondestructive Method to Evaluate of DC-DC Converters Using Subsurface Magnetic Field Imaging with Pulse Width Modulation

“…DC-DC converters are used to transform the voltage of lithium-ion batteries and other devices. The converters are widely used in many applications, such as electric vehicles (1) (2) , telecommunications (3) , medicine (4) , uninterruptible power supplies (5) (6) , and various consumer products (7) . In these applications, the converters failure induce a shutdown of the entire system.…”

State-of-the-Art Grid Stability Improvement Techniques for Electric Vehicle Fast-Charging Stations for Future Outlooks

“…The use of Evs has been heavily encouraged over the past ten years, as suggested in [5]. Consequently, Evs' growing popularity in the market has encouraged the development of other varieties of Evs, such as battery electric vehicles (BEVs) [6], hybrid vehicles (HVs) [7], fuel cell electric vehicles (FCEVs), and extended-range electric vehicles (ER-Evs) [8] for future exploration. Navigant Research has forecast a robust trend for global yearly EV adoption, as shown in Figure 1.…”